Emily Hilder

Poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) Monoliths by Spinodal Decomposition for Hydrodynamic Chromatography

Publisher: American Chemical Society (ACS)

Date: 20-06-2023

DOI: 10.1021/ACSAPM.3C00753

Separation of dithiocarbamate metal complexes by micellar electrokinetic chromatography

Publisher: Royal Society of Chemistry (RSC)

Date: 1998

DOI: 10.1039/A806306K

Synthesis of environmentally benign ultra-small copper nanoclusters-halloysite composites and their catalytic performance on contrasting azo dyes

Publisher: Elsevier BV

Date: 04-2021

DOI: 10.1016/J.APSUSC.2021.149122

Intraductal carcinoma of the prostate is an aggressive form of invasive carcinoma and should be graded

Publisher: Elsevier BV

Date: 02-2020

DOI: 10.1016/J.PATHOL.2019.11.001

Abstract: Infiltration of the prostatic ducts by prostatic adenocarcinoma occurs relatively frequently, being most commonly associated with high grade disease. It is now recognised that intraductal carcinoma of the prostate (IDCP) has an associated poor prognosis and this is reflected in its histological, molecular and immunohistochemical features. The current recommendation of the World Health Organization is that IDCP not be taken into consideration when grading prostate adenocarcinoma. It is apparent that Gleason did not differentiate between IDCP and stromal invasive carcinoma when developing and validating his grading system, and recent studies suggest that the incorporation of IDCP grading into the overall grading of the specimen provides additional prognostic information.

Tryptophan metabolism, its relation to inflammation and stress markers and association with psychological and cognitive functioning: Tasmanian Chronic Kidney Disease pilot study

Publisher: Springer Science and Business Media LLC

Date: 10-11-2016

DOI: 10.1186/S12882-016-0387-3

Effect of ethoxylated sorbitan ester surfactants on the chromatographic efficiency of poly(ethylene glycol)-based monoliths

Publisher: Elsevier BV

Date: 09-2021

DOI: 10.1016/J.CHROMA.2021.462464

Artificial intelligence for diagnosis and grading of prostate cancer in biopsies: a population-based, diagnostic study

Publisher: Elsevier BV

Date: 02-2020

DOI: 10.1016/S1470-2045(19)30738-7

Probing the kinetic performance limits for ion chromatography. II. Gradient conditions for small ions

Publisher: Elsevier BV

Date: 07-2010

DOI: 10.1016/J.CHROMA.2010.05.002

Abstract: A gradient kinetic plot method is used for theoretical characterisation of the performance of polymeric particulate anion exchange columns for gradient separations of small inorganic anions. The method employed requires only information obtained from a series of isocratic column performance measurements and in silico predictions of retention time and peak width under gradient conditions. Results obtained under practically constrained conditions provide parameters for the generation of high peak capacities and rapid peak production for fast analysis to be determined. Using this prediction method, a maximum theoretical peak capacity of 84 could be used to achieve separation of 26 components using a 120min gradient (R(s)>1). This approach provides a highly convenient tool for development of both mono- and multidimensional ion chromatography (IC) methodologies as it yields comprehensive understanding of the influence of gradient slope, analysis time, column length and temperature upon kinetically optimised gradient performance.

Separation of antidepressants by capillary electrophoresis with in-line solid-phase extraction using a novel monolithic adsorbent

Publisher: Elsevier BV

Date: 2006

DOI: 10.1016/J.ACA.2005.07.035

Abstract: The separation of three selective serotonin reuptake inhibitors (SSRIs) by capillary electrophoresis (CE) with fully integrated solid-phase extraction (SPE) is described. Polymeric monolithic SPE modules were prepared in situ within a fused silica capillary from either butyl methacrylate-co-ethylene dimethacrylate or 3-sulfopropyl methacrylate-co-butyl methacrylate-co-ethylene dimethacrylate. Using a 1cm SPE module placed at the inlet of the capillary, a mixture of sertraline, fluoxetine and fluvoxamine was extracted from aqueous solution by applying a simple pressure rinse. Under pressure-driven conditions, efficient elution was possible from both SPE materials investigated using 50mM phosphate buffer, pH 3.5 in acetonitrile (20/80, v/v). Two different strategies were investigated for the efficient elution and subsequent CE separation. Injection of an aqueous s le plug directly into the non-aqueous elution/separation buffer was found to be unsuitable with poor elution profiles observed in the electrodriven mode. Alternatively, a s le plug equivalent to several capillary volumes could be injected by pressure followed by filling the capillary with the non-aqueous elution/separation buffer from the outlet end using a combination of pressure and electrodriven flow. Using a neutral monolith, efficient elution/separation was not possible due to an unstable electroosmotic flow (EOF), however, by adding the ionisable monomer, 3-sulfopropyl methacrylate to the SPE module to increase and stabilise the EOF, it was possible to achieve efficient elution from the SPE module, followed by baseline separation by CE using a 200 mM acetate buffer, pH 3.5 in acetonitrile (10/90, v/v). With enrichment factors of over 500 achieved for each of the analytes this demonstrates the potential of in-line SPE-CE for the sensitive analysis of these drugs.

Non-ionic surface active agents as additives toward a universal porogen system for porous polymer monoliths

Publisher: American Chemical Society (ACS)

Date: 26-01-2021

DOI: 10.1021/ACS.ANALCHEM.0C03889

Robust open cellular porous polymer monoliths made from cured colloidal gels of latex particles

Publisher: Royal Society of Chemistry (RSC)

Date: 2018

DOI: 10.1039/C8GC01055B

Abstract: Preparation of polymer monoliths from the coagulation of particles, synthesized by soap-free emulsion polymerisation, using water as the only solvent.

Controversial issues in Gleason and International Society of Urological Pathology (ISUP) prostate cancer grading: proposed recommendations for international implementation

Publisher: Elsevier BV

Date: 08-2019

DOI: 10.1016/J.PATHOL.2019.05.001

Abstract: The Gleason Grading system has been used for over 50 years to prognosticate and guide the treatment for patients with prostate cancer. At consensus conferences in 2005 and 2014 under the guidance of the International Society of Urological Pathology (ISUP), the system has undergone major modifications to reflect modern diagnostic and therapeutic practices. The 2014 consensus conference yielded recommendations regarding cribriform, mucinous, glomeruloid and intraductal patterns, the most significant of which was the removal of any cribriform pattern from Gleason grade 3. Furthermore, a Gleason score grouping system was endorsed which consisted of five grades where Gleason score 6 (3+3) was classified as grade 1 which better reflected the mostly indolent behaviour of these tumours. Another issue discussed at the meeting and subsequently endorsed was that in Gleason score 7 cases, the percentage pattern 4 should be recorded. This is especially important in situations where modern active surveillance protocols expand to include men with low volume pattern 4. While major progress was made at the conference, several issues were either not resolved or not discussed at all. Most of these items relate to details of assignment of Gleason score and ISUP grade in specific specimen types and grading scenarios. This detailed review looks at the 2014 ISUP conference results and subsequent literature from an international perspective and proposes several recommendations. The specific issues addressed are percentage pattern 4 in Gleason score 7 tumours, percentage patterns 4 and 5 or 4/5 in Gleason score 8-10 disease, minor (≤5%) high grade patterns when either 2 or 3 patterns are present, level of reporting (core, specimen, case), dealing with grade ersity among site (highest and composite scores) and reporting scores in radical prostatectomy specimens with multifocal disease. It is recognised that for many of these issues, a strong evidence base does not exist, and further research studies are required. The proposed recommendations mostly reflect consolidated expert opinion and they are classified as established if there was prior agreement by consensus and provisional if there was no previous agreement or if the item was not discussed at prior consensus conferences. For some items there are reporting options that reflect the local requirements and erse practice models of the international urological pathology community. The proposed recommendations provide a framework for discussion at future consensus meetings.

Electro-osmotic and pressure-driven flow properties of frits for packed column capillary electrochromatography prepared from functionalised and bare silica packings

Publisher: Royal Society of Chemistry (RSC)

Date: 2000

DOI: 10.1039/A908102J

Green chromatographic fingerprinting: An environmentally friendly approach for the development of separation methods for fingerprinting complex matrices

Publisher: Wiley

Date: 22-11-2013

DOI: 10.1002/JSSC.201300955

Abstract: A chromatographic fingerprint is a comprehensive method that reveals the distinctive pattern of peaks across the chromatogram for a given s le. It is considered an effective strategy to assess the identity and quality of herbal materials, as well as for the control of the quality of their derived products. HPLC is the most employed technique for these purposes and it is used routinely for quality control in industry. Hence, its impact on the environment should not be neglected. This work provides a rational and generic procedure to qualitatively fingerprint complex matrices. Resource- and time-saving experimental designs were selected an alternative safer organic solvent was tested and a time-saving and innovative response entitled the green chromatographic fingerprinting response was developed and employed. This procedure was applied in the development of chromatographic fingerprints for extracts of Bauhinia forficata and Casearia sylvestris. Moreover, the response proposed here can be combined with a complementary metric available in the literature to compare methods using different solvents. According to this, the chromatographic fingerprints developed here using ethanol as the organic solvent provided a performance better than that of reference methods in which more harmful acetonitrile or methanol were employed.

Comparison of aqueous and nonaqueous carrier electrolytes for the separation of penicillin V and related substances by capillary electrophoresis with UV and mass spectrometric detection

Publisher: Wiley

Date: 02-2002

DOI: 10.1002/1522-2683(200202)23:3<414::AID-ELPS414>3.0.CO;2-K

LED controlled flow photolysis for concentration gradients in microfluidic systems

Publisher: Royal Society of Chemistry (RSC)

Date: 2010

DOI: 10.1039/C000258E

Abstract: Many of the channels and reservoirs in microfluidic systems are used simply to allow liquids with different compositions to be delivered to where they are needed. An alternative approach is to use dissolved photochemicals and variable intensity LEDs to generate composition changes in situ. We applied this approach to generate concentration gradients of HCl for gradient ion chromatography.

Highly ordered monolithic structures by directional freezing and UV-initiated cryopolymerisation. Evaluation as stationary phases in high performance liquid chromatography

Publisher: Royal Society of Chemistry (RSC)

Date: 2015

DOI: 10.1039/C5RA15114G

Abstract: Rigid aligned polymers were prepared by directional freezing and photo-initiated cryopolymerisation and tested as stationary phases in liquid chromatography.

Separation and sample pre-treatment in bioanalysis using monolithic phases: A review

Publisher: Elsevier BV

Date: 10-2009

DOI: 10.1016/J.ACA.2009.05.043

Abstract: In order to support drug discovery and development studies within the pharmaceutical industry there has been an increased use of innovative bioanalytical assays and associated analytical technology. Performing quantitative bioanalysis in a variety of biological matrices can also involve the use of s le preparation techniques, complex HLPC column switching and microfluidic systems. Development of assays for erse therapeutic agents in biomatrices, such as plasma and urine, can be very technically challenging to obtain the sensitivity, speed and specificity required. This challenge focuses on the quantification of drugs and metabolites at very low concentration levels, in an excess of biological matrix and in a high-throughput manner. One area of wide interest is the use and application of monolithic phases where emerging technology has been implemented successfully. This review presents an overview of the application of monolithic phases in a bioanalytical setting, including the bioanalytical challenges that need to be overcome the synthesis, use and applicability of monolithic phases (with emphasis on polymer-based phases) the currently available bioanalytical techniques and approaches and future possibilities for these phases.

Preconcentration by solvent removal: techniques and applications

Publisher: Springer Science and Business Media LLC

Date: 07-01-2019

DOI: 10.1007/S00216-018-1530-8

Abstract: Preconcentration is the aspect of analytical method development covering the need to improve detection sensitivity. This review collects the advances in a ersity of approaches to achieve preconcentration by solvent removal. Evaporation in microfluidic and paper-based devices is reported in a variety of forms and later compared to membrane-assisted evaporation. S le partitioning in an immiscible fluid is also described. The reported methodologies highlight the need to achieve good control of the gas-liquid interface to obtain accurate results. A comprehensive comparison of different strategies is presented here discussing their benefits and drawbacks as well as the research needs in this area. Graphical abstract ᅟ.

Using natural deep eutectic solvents for the extraction of metabolites in Byrsonima intermedia leaves

Publisher: Wiley

Date: 30-11-2018

DOI: 10.1002/JSSC.201800905

Abstract: Natural deep eutectic solvents have been used as an alternative to organic solvents for the extraction of plants metabolites, allowing for the extraction of compounds of different polarities, while being inexpensive, non-toxic, and easy to prepare. This work presents the comparison of the chromatographic profiles by high-performance liquid chromatography with diode-array detection obtained from Byrsonima intermedia (Malpighiaceae) using five choline chloride-based natural deep eutectic solvents, in addition to the most used traditional extraction solvents, methanol/water 7:3 and ethanol/water 7:3 v/v. A reference extract was used to tentatively identify compounds by high-performance liquid chromatography with tandem mass spectrometry. The water content appeared to be important for the extraction efficiency and the mixture choline chloride/glycerol was shown to be the best candidate for efficiently extracting this matrix when compared with the traditional extraction media in addition to being far greener as shown by the environmental analysis tool. Seven phenolic compounds (digalloyl quinic acid, proanthocyanidin dimer, galloylproanthocyanidin dimer, quercetin-O-hexoside, galloyl quercetin hexoside, quercetin-O-pentoside, and galloyl quercetin pentoside) were tentatively identified in all extracts. Moreover, the influence of these solvents on the antioxidant activity of the extracts was studied and the results for choline chloride/glycerol extracts were very similar to that of the traditional extraction solvents.

Molecular weight and tacticity of oligoacrylates by capillary electrophoresis-mass spectrometry

Publisher: CSIRO Publishing

Date: 2010

DOI: 10.1071/CH10088

Abstract: Oligo(acrylic acid) efficiently stabilizes polymeric particles, especially particles produced by reversible addition–fragmentation chain transfer (RAFT) (as hydrophilic block of an hiphilic copolymer). Capillary electrophoresis (CE) has a far higher resolution power to separate these oligomers than the commonly used size exclusion chromatography. Coupling CE to electrospray ionization mass spectrometric detection unravels the separation mechanism. CE separates these oligomers, not only according to their degree of polymerization, but also according to their tacticity, in agreement with NMR analysis. Such analysis will provide insight into the role of these oligomers as stabilizers in emulsion polymerization, and into the mechanism of the RAFT polymerization with respect to degree of polymerization and tacticity.

Focused issue - Reviews

Publisher: Wiley

Date: 04-2011

DOI: 10.1002/JSSC.201190014

Emerging Investigators Special Issue

Publisher: Royal Society of Chemistry (RSC)

Date: 2006

DOI: 10.1039/B600451M

Evaporative membrane modulation for comprehensive two-dimensional liquid chromatography

Publisher: Elsevier BV

Date: 02-2018

DOI: 10.1016/J.ACA.2017.11.053

Abstract: An evaporative membrane modulator was developed, built and evaluated to avoid loss of performance in the second dimension when coupling two-dimensional liquid chromatography systems. The automated interface reduces the volume after

Impact of mobile phase composition on the performance of porous polymeric monoliths in the elution of small molecules

Publisher: Elsevier BV

Date: 11-2012

DOI: 10.1016/J.CHROMA.2012.09.033

Abstract: The influence of mobile phase solvent composition and consequently retention factor on the chromatographic performance for a set of small molecules was studied using a commercially available poly(styrene-co- inyl benzene) analytical scale porous polymeric monolithic column as an ex le. Chromatographic elution performance was studied across retention factors from close to 0 up to 100 realized for a set of structurally similar small molecules in a binary reversed-phase solvent environment of acetonitrile and water. By altering the mobile phase composition from volume fractions of acetonitrile of just 10% (v/v) to only acetonitrile it was systematically shown that gel porosity of the monolithic column plays a dominant role in modulating mass transport and the associated chromatographic efficiency in a consistent manner. Up to a sixfold difference in plate height was recorded for the most strongly retained hydrophobic solute (ethylbenzene) at a constant, low flow velocity simply by varying the amount of acetonitrile in the mobile phase. Plate height curves recorded for the set of solutes that comprise benzene, toluene, ethylbenzene as well as phenol and benzyl alcohol further demonstrate the importance of functional group content of the solute and the modulated porous gel structure on mass transport. These results highlight some important practical considerations for characterizing the chromatographic properties of any polymeric monolithic column. First, it is imperative that any chromatographic performance characterization using plate height data explicitly considers the influence of mobile phase composition, retention factor, molecular size and functional groups of the probe solute. Second, as the physicochemical conditions of the material are directly reflected in the gel porosity, a range of different mobile phase compositions, retention factors and probe-specific effects must be investigated to yield a fair appraisal of the chromatographic performance.

Fabrication of porous polymer monoliths covalently attached to the walls of channels in plastic microdevices

Publisher: Wiley

Date: 11-2003

DOI: 10.1002/ELPS.200305536

Abstract: UV-initiated grafting of plastic tubes and microfluidic chips with ethylene diacrylate followed by the preparation of porous polymer monoliths has been studied. The first step affords a thin grafted layer of polymer with a multiplicity of pendent double bonds that are then used in the second step for covalent attachment of the monolith to the wall. As clearly seen on scanning electron micrographs, this procedure prevents the formation of voids at the monolith-channel interface a problem that has always plagued approaches involving bulk polymerization in nontreated channels due to the shrinkage of the monolith during the polymerization process and its lack of compatibility with the material of the device. Irradiation with UV light through a photomask allows precise patterning specifying both the area subjected to surface modification and the location of the monolith within specific areas of the device.

Online sample pre-concentration via dynamic pH junction in capillary and microchip electrophoresis

Publisher: Wiley

Date: 10-2011

DOI: 10.1002/JSSC.201100414

Abstract: Various analytical techniques have been developed over the years to analyse a large ersity of biomolecules with a constant push towards ultra-sensitive detection. CE is at the forefront of the most powerful analytical tools available to date when considering its superior efficiency and resolution however, the technique suffers from poor sensitivity as a result of the short path length at the detection site and small injection volumes (typically <1% capillary length). One of the approaches to abate the inherent problem is to employ clever chemistry using s le focusing techniques whereby a large s le plug can be injected, preconcentrated and separated, producing excellent sensitivity and efficiency at the detector. This particular review will focus on the use of dynamic pH junction as a means of improving sensitivity in CE and focuses on the use of a change in analyte ionisation due to different pHs between the s le and electrolyte. The review provides a fundamental discussion of the mechanisms, buffer and s le conditions required to concentrate various analytes and a comprehensive list of published works in tabular format for easy identification of suitable conditions for new applications. The review further encompasses the use of dynamic pH junction in CE and its involvement in combination with other preconcentrations techniques to produce high sensitivity enhancements recorded between the years 1990-2010.

Micellar electrokinetic chromatography of organic and peroxide-based explosives

Publisher: Elsevier BV

Date: 05-2015

DOI: 10.1016/J.ACA.2015.02.070

Abstract: CE methods have been developed for the analysis of organic and peroxide-based explosives. These methods have been developed for deployment on portable, in-field instrumentation for rapid screening. Both classes of compounds are neutral and were separated using micellar electrokinetic chromatography (MEKC). The effects of s le composition, separation temperature, and background electrolyte composition were investigated. The optimised separation conditions (25 mM sodium tetraborate, 75 mM sodium dodecyl sulfate at 25°C, detection at 200 nm) were applied to the separation of 25 organic explosives in 17 min, with very high efficiency (typically greater than 300,000 plates m(-1)) and high sensitivity (LOD typically less than 0.5 mg L(-1) around 1-1.5 μM). A MEKC method was also developed for peroxide-based explosives (10 mM sodium tetraborate, 100 mM sodium dodecyl sulfate at 25°C, detection at 200 nm). UV detection provided LODs between 5.5 and 45.0 mg L(-1) (or 31.2-304 μM), which is comparable to results achieved using liquid chromatography. Importantly, no s le pre-treatment or post-column reaction was necessary and the peroxide-based explosives were not decomposed to hydrogen peroxide. Both MEKC methods have been applied to pre-blast analysis and for the detection of post-blast residues recovered from controlled, small scale detonations of organic and peroxide-based explosive devices.

Pathology Imagebase-a reference image database for standardization of pathology

Publisher: Wiley

Date: 13-09-2017

DOI: 10.1111/HIS.13313

Abstract: Despite efforts to standardize histopathology practice through the development of guidelines, the interpretation of morphology is still h ered by subjectivity. We here describe Pathology Imagebase, a novel mechanism for establishing an international standard for the interpretation of pathology specimens. The International Society of Urological Pathology (ISUP) established a reference image database through the input of experts in the field. Three panels were formed, one each for prostate, urinary bladder and renal pathology, consisting of 24 international experts. Each of the panel members uploaded microphotographs of cases into a non-public database. The remaining 23 experts were asked to vote from a multiple-choice menu. Prior to and while voting, panel members were unable to access the results of voting by the other experts. When a consensus level of at least two-thirds or 16 votes was reached, cases were automatically transferred to the main database. Consensus was reached in a total of 287 cases across five projects on the grading of prostate, bladder and renal cancer and the classification of renal tumours and flat lesions of the bladder. The full database is available to all ISUP members at www.isupweb.org. Non-members may access a selected number of cases. It is anticipated that the database will assist pathologists in calibrating their grading, and will also promote consistency in the diagnosis of difficult cases.

Pressurized-flow anion-exchange capillary electrochromatography using a polymeric ion-exchange stationary phase

Publisher: Elsevier BV

Date: 08-2000

DOI: 10.1016/S0021-9673(00)00612-9

Abstract: The feasibility of using capillary columns equipped with silica frits and packed with a polymer-based anion exchanger (Dionex AS9-HC) for CEC separations of inorganic anions has been investigated. Experiments using a conventional 25 cm packed bed, and mobile phase flow that is a combination of hydrodynamic and electroosmotic flow were used to demonstrate that by varying the applied voltage (electrophoresis component) or the concentration of the competing ion in the mobile phase (ion-exchange component), considerable changes in the separation selectivity could be obtained. Using an artificial neural network, this separation system was modelled and the results obtained used to determine the optimum conditions (9 mM perchlorate and--10 kV) for the separation of eight inorganic anions. When a short (8 cm) packed bed was used, with detection immediately following the packed section, the separation of eight test analytes in under 2.2 min was possible using pressure-driven flow and a simple step voltage gradient. A more rapid separation of these analytes was obtained by only applying high voltage (-30 kV), where many of the same analytes were separated in less than 20 s and with a different separation selectivity to that obtained in conventional ion-exchange or capillary electrophoresis separations.

A trade off between separation, detection and sustainability in liquid chromatographic fingerprinting

Publisher: Elsevier BV

Date: 08-2014

DOI: 10.1016/J.CHROMA.2014.05.018

Abstract: It is now recognized that analytical chemistry must also be a target for green principles, in particular chromatographic methods which typically use relatively large volumes of hazardous organic solvents. More generally, high performance liquid chromatography (HPLC) is employed routinely for quality control of complex mixtures in various industries. Acetonitrile and methanol are the most commonly used organic solvents in HPLC, but they generate an impact on the environment and can have a negative effect on the health of analysts. Ethanol offers an exciting alternative as a less toxic, biodegradable solvent for HPLC. In this work we demonstrate that replacement of acetonitrile with ethanol as the organic modifier for HPLC can be achieved without significantly compromising analytical performance. This general approach is demonstrated through the specific ex le analysis of a complex plant extract. A benchmark method employing acetonitrile for the analysis of Bidens pilosa extract was statistically optimized using the Green Chromatographic Fingerprinting Response (GCFR) which includes factors relating to separation performance and environmental parameters. Methods employing ethanol at 30 and 80°C were developed and compared with the reference method regarding their performance of separation (GCFR) as well as by a new metric, Comprehensive Metric to Compare Liquid Chromatography Methods (CM). The fingerprint with ethanol at 80°C was similar to or better than that with MeCN according to GCFR and CM. This demonstrates that temperature may be used to replace harmful solvents with greener ones in HPLC, including for solvents with significantly different physiochemical properties and without loss in separation performance. This work offers a general approach for the chromatographic analysis of complex s les without compromising green analytical chemistry principles.

Temperature pulsing for controlling chromatographic resolution in capillary liquid chromatography

Publisher: American Chemical Society (ACS)

Date: 19-03-2012

DOI: 10.1021/AC300161B

Abstract: In this study we introduce the implementation of rapid temperature pulses for selectivity tuning in capillary liquid chromatography. Short temperature pulses improved resolution in discrete sections of chromatograms, demonstrated for ion-exchange chromatography (IC) and hydrophilic interaction chromatography (HILIC) modes. Using a resistively heated column module capable of accurate and rapid temperature changes, this concept is first illustrated with separations of small anions by IC using a packed capillary column as well as a series of nucleobases and nucleosides by HILIC using a silica monolithic column with zwitterionic functionality (ZIC-HILIC). Both positive (increasing temperature) and negative temperature pulses are demonstrated to produce significant changes in selectivity and are useful approaches for improving resolution between coeluted compounds. The approach was shown to be reproducible over a large number of replicates. Finally, the use of temperature gradients as well as other complex temperature profiles was also examined for both IC and HILIC separations.

Shielded Stationary Phases Based on Porous Polymer Monoliths for the Capillary Electrochromatography of Highly Basic Biomolecules

Publisher: American Chemical Society (ACS)

Date: 18-05-2004

DOI: 10.1021/AC049732Q

Abstract: A novel stationary phase for capillary electrochromatography has been prepared via photoinitiated grafting of two layers of polymer chains onto the pore surface of a porous polymer monolith. To achieve the desired retention, the original monolith with optimized porous properties was grafted with an "interior" layer consisting of the ionizable monomer, 2-acrylamido-2-methyl-1-propanesulfonic acid, followed by a "covering" layer of hydrophobic polymer chains. This technique affords monolithic CEC columns that facilitate electroosmotic flow (EOF) while preventing ionized analytes from interacting with the charged surface functionalities. Grafting of the second layer does not adversely affect the EOF. Grafting times of 30 and 60 s for AMPS and butyl acrylate, respectively, enabled the preparation of a monolith with full shielding of the analytes from the ionizable functionalities and excellent chromatographic performance. This approach allows for the first time the independent optimization of both electroosmotic flow and retention properties in CEC columns. The efficient isocratic separations of mixtures of peptides, including some that are highly basic and would be affected by unshielded charges, were routinely achieved in 40-90 s using a simple MS compatible mobile phase consisting of 20 mmol/L ammonium acetate in a 1:1 water-acetonitrile mixture.

Assessment of the complementarity of temperature and flow-rate for response normalisation of aerosol-based detectors

Publisher: Elsevier BV

Date: 08-2014

DOI: 10.1016/J.CHROMA.2014.06.055

Abstract: The solvent dependency of the detection response is a major limitation of corona-charged aerosol detection (C-CAD). The present study empirically investigates the utility of temperature and flow-rate gradients to overcome solvent gradient limitations of C-CAD. In preliminary flow-injection investigations, it is demonstrated that the response of C-CAD remains relatively unaltered with variations in flow-rate when used with water-rich eluents. Based on these findings two separation approaches were developed and their utility for C-CAD response normalisation was demonstrated using a mixture of eight analytes. In the first approach the use of a solvent gradient is replaced with a temperature gradient performed under isocratic mobile phase conditions. Detection response is further enhanced by mixing a secondary stream of pure acetonitrile with the column effluent, yielding a 3-fold increase in detection response. In the second approach, flow-rate programming is used to improve speed of isocratic-temperature gradient separation. The use of simultaneous variation in flow-rate and column temperature reduced the separation time by 30%, with relatively uniform analyte response. Lastly, an inverse-gradient solvent compensation approach was used to evaluate the response homogeneity and the applicability of the above approaches for quantitative analysis. Good peak area reproducibility (RSD% 0.994, on a log-scale) over the s le mass range of 0.1-10 μg was achieved. The response deviation across the mixture of eight compounds at seven concentration levels was 6-13% compared to 21-39% when a conventional solvent gradient was applied and this response deviation was comparable to that obtained in the inverse gradient solvent compensation approach. Finally, applicability of these approaches for typical pharmaceutical impurity profiling was demonstrated at a concentration of 5 μg/mL (0.1% of the principal compound).

Separation of inorganic anions on a high capacity porous polymeric monolithic column and application to direct determination of anions in seawater

Publisher: Wiley

Date: 08-2008

DOI: 10.1002/JSSC.200800205

Abstract: A commercially available 4.6 mm id x 50 mm polymethacrylate-based monolithic strong anion exchange column (ProSwift SAX-1S) designed for the separation of proteins has been successfully used to separate small inorganic anions in the presence of a seawater s le matrix. Using a hydroxide eluent with suppressed conductivity detection the ion exchange capacity of this column declined over time however, using KCl as the eluent, the column performance was stable with a capacity of 530 microequiv. for nitrate. The optimum conditions for the separation of iodate, bromate, nitrite, bromide and nitrate were assessed by constructing van Deemter plots using 1.00 and 0.100 M KCl. Efficiencies of up to 26 700 plates/m were recorded using 1.00 M KCl, at a flow rate of 0.20 mL/min but iodate was not baseline resolved from the void peak. By reducing the concentration of the eluent to 0.100 M, efficiencies of up to 39 900 plates/m could be obtained at 0.35 mL/min. By employing a linear gradient ranging from 0.05 to 1.00 M KCl the ions dissolved in distilled water or a salt water matrix could be baseline separated in less than 3 min at a flow rate of 2.50 mL/min.

Biocompatible functionalisation of nanoclays for improved environmental remediation.

Publisher: Royal Society of Chemistry (RSC)

Date: 2019

DOI: 10.1039/C8CS01019F

Abstract: Among the wide range of materials used for remediating environmental contaminants, modified and functionalised nanoclays show particular promise as advanced sorbents, improved dispersants, or biodegradation enhancers. However, many chemically modified nanoclay materials are incompatible with living organisms when they are used in natural systems with detrimental implications for ecosystem recovery. Here we critically review the pros and cons of functionalised nanoclays and provide new perspectives on the synthesis of environmentally friendly varieties. Particular focus is given to finding alternatives to conventional surfactants used in modified nanoclay products, and to exploring strategies in synthesising nanoclay-supported metal and metal oxide nanoparticles. A large number of promising nanoclay-based sorbents are yet to satisfy environmental biocompatibility in situ but opportunities are there to tailor them to produce "biocompatible" or regenerative/reusable materials.

Recent advances in polymer monoliths for ion-exchange chromatography

Publisher: Springer Science and Business Media LLC

Date: 11-02-2009

DOI: 10.1007/S00216-009-2636-9

Abstract: The use of polymeric materials in ion-exchange chromatography applications is advantageous because of their typically high mechanical stability and tolerance of a wide range of pH conditions. The possibility of using polymeric monoliths in ion-exchange chromatography is therefore obvious and many of the same strategies developed for polymeric particles have been adapted for use with polymeric monoliths. In this review different strategies for the synthesis of polymeric monoliths with ion-exchange functionality are discussed. The incorporation of ion-exchange functionality by co-polymerization is included, as also are different post-polymerization alterations to the monolith surface such as grafting. The formulations and strategies presented include materials intended for use in analytical separations in ion-exchange chromatography, s le pre-treatment or enrichment applications, and materials for capillary electrochromatography. Finally, ex les of the use of polymeric monoliths in ion-exchange chromatography applications are included with ex les published in the years 2003 to 2008.

Prostate Cancer Grading: A Decade After the 2005 Modified Gleason Grading System

Publisher: Archives of Pathology and Laboratory Medicine

Date: 02-2017

DOI: 10.5858/ARPA.2016-0300-LE

Use of ionic polymers as stationary and pseudo-stationary phases in the separation of ions by capillary electrophoresis and capillary electrochromatography

Publisher: Elsevier BV

Date: 2002

DOI: 10.1016/S0021-9673(01)01403-0

Abstract: One of the problems with capillary electrophoresis is a lack of versatility regarding manipulation of the separation selectivity. A new and potentially universal concept is to introduce an ion-exchange component into a separation so that the migration of analyte ions is influenced by both their electrophoretic mobilities and their chromatographic properties. This may be accomplished by use of capillaries filled with or coated with solid ion-exchange polymers, or by addition of a soluble ionic polymer to the background electrolyte to create a pseudo-stationary phase. While each of these methods achieves the same result, they are not competitive, but rather complementary as the problems associated by one approach are overcome by the others. Recent highlights in the field are used to illustrate the flexibility that this approach provides to electrophoretic separation of ions.

On-line simultaneous and rapid separation of anions and cations from a single sample using dual-capillary sequential injection-capillary electrophoresis

Publisher: Elsevier BV

Date: 06-2013

DOI: 10.1016/J.ACA.2013.03.027

Abstract: A novel capillary electrophoresis (CE) approach has been developed for the simultaneous rapid separation and identification of common environmental inorganic anions and cations from a single s le injection. The method utilised a sequential injection-capillary electrophoresis instrument (SI-CE) with capacitively-coupled contactless conductivity detection (C(4)D) constructed in-house from commercial-off-the-shelf components. Oppositely charged analytes from a single s le plug were simultaneously injected electrokinetically onto two separate capillaries for independent separation and detection. Injection was automated and may occur from a syringe or be directly coupled to an external source in a continuous manner. Software control enabled high s le throughput (17 runs per hour for the target analyte set) and the inclusion of an isolation valve allowed the separation capillaries to be flushed, increasing throughput by removing slow migrating species as well as improving repeatability. Various environmental and industrial s les (subjected only to filtering) were analysed in the laboratory with a 3 min analysis time which allowed the separation of 23 inorganic and small organic anions and cations. Finally, the system was applied to an extended automated analysis of Hobart Southern Water tap water for a period of 48 h. The overall repeatability of the migration times of a 14 analyte standard s le was less than 0.74% under laboratory conditions. LODs ranged from 5 to 61 μg L(-1). The combination of automation, high confidence of peak identification, and low limits of detection make this a useful system for the simultaneous identification of a range of common inorganic anions and cations for discrete or continuous monitoring applications.

Electrokinetic Chromatography and Mass Spectrometric Detection Using Latex Nanoparticles as a Pseudostationary Phase

Publisher: American Chemical Society (ACS)

Date: 19-04-2010

DOI: 10.1021/AC902922U

Abstract: The utility of novel latex nanoparticles as pseudostationary phases for electrokinetic chromatography with UV and mass spectrometric detection is demonstrated. The nanoparticles are synthesized using ab initio RAFT (reversible addition-fragmentation chain transfer) in emulsion polymerization, which yields small (63 nm) particles with a narrow size distribution, a hydrophobic core, and an ionic shell. The nanoparticles are shown to provide efficient and selective separations, with retention and separation selectivity dominated by hydrophobic interactions. The nanoparticles are highly retentive, such that they are effective at relatively low concentrations. Addition of the nanoparticles to the background electrolyte at these concentrations has a minor effect on the noise with UV detection, no measurable effect on the separation current, and minor effects on analyte ionization efficiency during electrospray ionization. The nanoparticles do not cause fouling or degradation of the electrospray-mass spectrometer interface even after several weeks of use. The combination of online s le preconcentration via sweeping and selective mass spectrometric detection yields low detection limits (10-16 ppb), particularly for more hydrophobic compounds.

High-resolution separation of oligo(acrylic acid) by capillary zone electrophoresis

Publisher: Wiley

Date: 19-12-2006

DOI: 10.1002/MARC.200500641

Applications of resistive heating in gas chromatography: A review

Publisher: Elsevier BV

Date: 11-2013

DOI: 10.1016/J.ACA.2013.04.063

Abstract: Gas chromatography is widely applied to separate, identify, and quantify components of s les in a timely manner. Increasing demand for analytical throughput, instrument portability, environmental sustainability, and more economical analysis necessitates the development of new gas chromatography instrumentation. The applications of resistive column heating technologies have been espoused for nearly thirty years and resistively heated gas chromatography has been commercially available for the last ten years. Despite this lengthy period of existence, resistively heated gas chromatography has not been universally adopted. This low rate of adoption may be partially ascribed to the saturation of the market with older convection oven technology, coupled with other analytical challenges such as s ling, injection, detection and data processing occupying research. This article assesses the advantages and applications of resistive heating in gas chromatography and discusses practical considerations associated with adoption of this technology.

Probing the kinetic performance limits for ion chromatography. I. Isocratic conditions for small ions

Publisher: Elsevier BV

Date: 07-2010

DOI: 10.1016/J.CHROMA.2010.05.066

Abstract: The first use of the kinetic plot method to characterise the performance of ion-exchange columns for separations of small inorganic anions is reported. The influence of analyte type (mono- and alent), particle size (5 and 9microm), temperature (30 and 60 degrees C) and maximum pressure drop upon theoretical extrapolations was investigated using data collected from anion-exchange polymeric particulate columns. The quality of extrapolations was found to depend upon the choice of analyte, but could be verified by coupling a series of columns to demonstrate some practical solutions for ion chromatography separations requiring relatively high efficiency. Separations of small anions yielding 25-40,000 theoretical plates using five serially connected columns (9microm particles) were obtained and yielded deviations of <15% from the kinetic plot predictions. While this approach for achieving high efficiencies results in a very long analysis time (t(0)=21min), separations yielding approximately 10,000 theoretical plates using two serially connected columns (t(0) 10min).

Natural deep eutectic solvents and aqueous solutions as an alternative extraction media for propolis

Publisher: Elsevier BV

Date: 11-2019

DOI: 10.1016/J.FOODRES.2019.108559

Abstract: Ethanolic extracts of propolis are consumed for their health benefits even though direct consumption of alcoholic extracts is not always ideal. Natural Deep Eutectic Solvents (NADES) can potentially extract similar compounds as alcoholic extracts while being better for direct consumption. Therefore, in this work alternative solvents for the extraction of green propolis including its biomarker artepillin C were examined. Sixteen NADES made from low toxicity chemicals, including the essential amino acid l-lysine, were explored along with twelve in idual NADES components and honey, which showed similar physical-chemical properties to NADES. At 50 °C NADES made from choline chloride-propylene glycol or lactic acid proved to be equal or better than the benchmark EtOH:Water 7:3 (v/v). Alternatively, aqueous l-lysine appeared as a potential solvent for the preparation of aqueous propolis extracts. From these findings NADES, honey and aqueous l-lysine solutions all demonstrated the potential to replace ethanol or water for extracting green propolis.

Editorial

Publisher: Elsevier BV

Date: 12-2008

DOI: 10.1016/J.CHROMA.2008.10.044

Fast ion chromatography using short anion exchange columns

Publisher: Elsevier BV

Date: 11-2009

DOI: 10.1016/J.CHROMA.2009.10.003

Abstract: A fast ion chromatographic system is described which uses shorter column lengths and compares various eluent profiles in order to maximise the performance without sacrificing the chromatographic resolution. Both isocratic and gradient elution profiles were considered to find the most efficient mode of separation. The separation and determination of seven target anions (chloride, chlorate, nitrate, chromate, sulfate, thiocyanate and perchlorate) was achieved using a short (4mm ID, 50mm long) column packed with Dionex AS20 high-capacity anion exchange material. A hydroxide eluent was used at an initial concentration of 25 mM (at a flow-rate of 1.0 mL/min) and two performance maxima were found. The maximum efficiency occurred at a normalised gradient r rate of 5mM/t(0), resulting in a peak capacity of 16, while the fastest separation (<3 min) occurred at a normalised r rate of 30 mM/t(0). The retention time, peak width and resolution using the different eluent profiles on varying column lengths is also compared. Further investigations in this study determined that the highest peak capacity separation under gradient conditions could be approximated using an isocratic separation. The advantage of using this novel approach to approximate the maximum efficiency separation removes the need for column re-equilibration that is required for gradient elution resulting in faster analyses and enhanced s le throughput, with benefits in particular for multidimensional chromatography.

Utilizing RAFT Polymerization for the Preparation of Well-Defined Bicontinuous Porous Polymeric Supports: Application to Liquid Chromatography Separation of Biomolecules

Publisher: American Chemical Society (ACS)

Date: 30-06-2021

DOI: 10.1021/ACSAMI.1C03542

The Complexity and Dynamics of the Tissue Glycoproteome Associated With Prostate Cancer Progression

Publisher: Elsevier BV

Date: 2021

DOI: 10.1074/MCP.RA120.002320

Separation of hydrophobic polymer additives by microemulsion electrokinetic chromatography

Publisher: Elsevier BV

Date: 07-2001

DOI: 10.1016/S0021-9673(01)00950-5

Abstract: Microemulsion electrokinetic chromatography (MEEKC) has been applied to the separation of some phenolic antioxidants [Irganox 1024, Irganox 1035, Irganox 1076, Irganox 1010, Irganox 1330, Irgafos 138, Irganox 168 and 2,6-di-tert.-butyl-4-methylphenol (BHT)]. Due to the extremely hydrophobic nature of these analytes, they could not be separated using standard MEEKC conditions and two alternative approaches were investigated. Using an acidic buffer (phosphate, pH 2.5) to effectively suppress the electroosmotic flow, the addition of 2-propanol to the aqueous phase of the microemulsion buffer to improve partitioning of the analytes, and a negative separation voltage, separation of five of the analytes in under 10 min was possible. The second approach, using a basic buffer (borate, pH 9.2) and a positive separation voltage resulted in complete resolution of all eight analytes. A mixed surfactant system comprising the anionic sodium dodecyl sulfate (SDS) and neutral Brij 35 was used to reduce the overall charge and with it the mobility of the droplets, and hence the separation time. Using an optimised MEEKC buffer consisting of 2.25% (w/w) SDS, 0.75% (w/w) Brij 35, 0.8% (w/w) n-octane, 6.6% (w/w) 1-butanol, 25% (w/w) 2-propanol and 64.6% (w/w) 10 mM borate buffer (pH 9.2) the eight target analytes were baseline separated in under 25 min. For these analytes, MEEKC was found to be superior to micellar electrokinetic chromatography in every respect. Specifically, the solubility of the analytes was better, the selectivity was more favourable, the analysis time was shorter and the separation efficiency was up to 72% higher when using the MEEKC method. Detection limits from 5.4 to 26 microg/ml were obtained and the calibration plot was linear over more than one order of magnitude. The optimised method could be applied to the determination of Irganox 1330 and Irganox 1010 in polypropylene.

Monolithic cryopolymers with embedded nanoparticles. II. Capillary liquid chromatography of proteins using charged embedded nanoparticles

Publisher: Elsevier BV

Date: 10-2013

DOI: 10.1016/J.CHROMA.2013.08.077

Abstract: The preparation of composite monolithic cryopolymers is presented. These novel porous materials were prepared in capillary format at -70°C using poly(ethyleneglycol) diacrylate (PEGDA) Mw 258 as the single monomer and a mixture of dioxane and water as the porogen. Positively (NR4(+)) or negatively (SO3(-)) charged nanoparticles were incorporated within the polymeric structure by direct addition of their suspensions to the polymerisation mixture. In contrast to our previous report using neutral nanoparticles, the trapping of charged nanoparticles is mostly observed at the polymer surface. The incorporation of these nanostructures improved the chromatographic separations of standard proteins under a hydrophobic interaction chromatography (HIC) separation mode. Moreover, the presence of ionic groups on the polymer surface allowed the application of these columns under ion-exchange (IEX) conditions. The results obtained in this work show that the functionalisation of monolithic columns by direct addition of nanoparticles is a good alternative towards the modification of monolithic polymers without altering the polymeric scaffold.

On-line solvent exchange system: Automation from extraction to analysis

Publisher: Elsevier BV

Date: 2019

DOI: 10.1016/J.ACA.2018.09.044

Abstract: Removal of organic solvent from s le extracts is required before analysis by reversed phase HPLC to preserve chromatographic performance and allow for bigger injection volumes, boosting sensitivity. Herein, an automated on-line extraction evaporation procedure is integrated with HPLC analysis. The evaporation occurs inside a 200 μm microfluidic channel confined by a vapor permeable membrane. A feedback control algorithm regulates evaporation rate keeping the output flow rate constant. The evaporation process across this membrane was firstly characterized with water/solvent mixtures showing organic solvent removal capabilities. This system allowed continuous methanol, ethanol and acetonitrile removal from s les containing up to 80% organic solvent. An evaporative injection procedure was developed demonstrating the use of the device for fully integrated extract reconstitution coupled to HPLC analysis, applied to analysis of the antibiotic chlor henicol in milk s les. S le reconstitution and collection was performed in less than 10 min and can be executed simultaneously to HPLC analysis of the previous s le in a routine workflow, thus having minimal impact on the total s le analysis time when run in a sequence.

Porous polymer monolith for surface‐enhanced laser desorption/ionization time‐of‐flight mass spectrometry of small molecules

Publisher: Wiley

Date: 03-06-2004

DOI: 10.1002/RCM.1515

Abstract: Porous poly(butyl methacrylate-co-ethylene dimethacrylate), poly(benzyl methacrylate-co-ethylene dimethacrylate), and poly(styrene-co- inylbenzene) monoliths have been prepared on the top of standard s le plates used for matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and the modified plates were used for laser desorption/ionization mass spectrometry (LDI-MS). The hydrophobic porous surface of these monoliths enables the transfer of sufficient energy to the analyte to induce desorption and ionization prior to TOFMS analysis. Both UV and thermally initiated polymerization using a mask or circular openings in a thin gasket have been used to define spot locations matching those of the MALDI plates. The desorption/ionization ability of the monolithic materials depends on the applied laser power, the solvent used for s le preparation, and the pore size of the monoliths. The monolithic matrices are very stable and can be used even after long storage times in a typical laboratory environment without observing any deterioration of their properties. The performance of the monolithic material is demonstrated with the mass analysis of several small molecules including drugs, explosives, and acid labile compounds. The macroporous spots also enable the archiving of s les.

Preparation and characterisation of anion-exchange latex-coated silica monoliths for capillary electrochromatography

Publisher: Elsevier BV

Date: 03-2006

DOI: 10.1016/J.CHROMA.2005.08.076

Abstract: Silica monoliths coated with functionalised latex particles have been prepared for use in monolithic ion-exchange capillary electrochromatography (IE-CEC) for the separation of inorganic anions. The ion-exchange monoliths were prepared using 70 nm quaternary ammonium, anion-exchange latex particles, which were bound electrostatically to a monolithic silica skeleton synthesised in a fused silica capillary. The resulting stationary phases were characterised in terms of their chromatographic performance and capacity. The capacity of a 50 microm diameter 25 cm latex-coated silica monolith was found to be 0.342 nanoequivalents and 80,000 theoretical plates per column were typically achieved for weakly retained anions, with lower efficiency being observed for analytes exhibiting strong ion-exchange interaction with the stationary phase. The electroosmotic flow (EOF) was reversed after the latex-coating was applied (-25.96 m2 V(-1) s(-1), relative standard deviation (RSD) 2.8%) and resulted in anions being separated in the co-EOF mode. Ion-exchange interactions between the analytes and the stationary phase were manipulated by varying the ion-exchange selectivity coefficient and the concentration of a competing ion (phosphate or perchlorate) present in the electrolyte. Large concentrations of competing ion (greater than 1M phosphate or 200 mM perchlorate) were required to completely suppress ion-exchange interactions, which highlighted the significant retention effects that could be achieved using monolithic columns compared to open tubular columns, without the problems associated with particle-packed columns. The latex-coated silica monoliths were easily produced in bulk quantities and performed reproducibly in acidic electrolytes. The high permeability and beneficial phase ratio makes these columns ideal for micro-LC and preconcentration applications.

Monolithic high-performance liquid chromatography columns

Publisher: Wiley

Date: 25-03-2017

DOI: 10.1002/9780470027318.A9386

Abstract: Monolithic HPLC (high‐performance liquid chromatography) columns have emerged over the recent decades as highly attractive alternatives to conventional HPLC technology. A monolith is considered to be a continuous piece of porous material. Two types of monolithic columns have been developed for liquid chromatography (LC) applications they are polymer monoliths and silica monoliths, which differ based on their porous properties. Polymer monoliths consist solely of macropores (pores larger than 50 nm), while silica monoliths possess both macropores and mesopores (pores between 2 and 50 nm). Silica monoliths therefore possess higher surface areas than polymer monoliths and have mainly been utilied for the separation of small molecules, where excellent separation performance has been demonstrated. Polymer monoliths on the other hand have been shown to provide excellent separation performance for larger molecules, where the convective transport of these molecules is unhindered by the presence of mesopores. Polymer and silica monoliths can be prepared in a variety of ways, resulting in varied surface chemistries and flow properties, thus allowing their application in a wide range of chromatographic modes, including reversed‐phase (RP), ion‐exchange, hydrophilic interaction, and hydrophobic interaction chromatography (HIC), to name a few. This has allowed for the separation of a variety of analytes, from small molecules such as alkylbenzenes, to larger molecules such as peptides and proteins. They have also found application for the separation of DNA. In recent years, significant attention has been focused on improving and understanding the behavior of these materials and alternative synthetic routes for their preparation.

Packing procedures for high efficiency, short ion-exchange columns for rapid separation of inorganic anions

Publisher: Elsevier BV

Date: 10-2008

DOI: 10.1016/J.CHROMA.2008.08.056

Abstract: An optimised packing procedure for the production of high efficiency, short, particle-packed ion-exchange columns is reported. Slurry-packing techniques were applied to a series of interconnected short columns, with the columns situated intermediate between the inlet and outlet ends of the series being used for separations. The fast separation and determination of inorganic anions was achieved using short (4mm ID, 30mm long) columns packed with Dionex AS20 high-capacity anion-exchange stationary phase. Seven inorganic anions (bromate, chloride, chlorate, nitrate, sulfate, chromate and perchlorate) are separated in 2.6min using a hydroxide gradient and a flow-rate of 1.8mL/min (total analysis time including re-equilibration was 3.5min). Under isocratic conditions, the home-packed columns exhibited efficiency values of 43,000N/m for chloride at a flow-rate of 0.3mL/min, compared to 54,000N/m for a commercial 250mm AS20 column at the same flow-rate. However, the short columns gave approximately a threefold higher s le throughput. The short, home-packed columns could be produced reproducibly and gave consistent performance over extended periods of usage.

Investigations on the behaviour of acidic, basic and neutral compounds in capillary electrochromatography on a mixed-mode stationary phase

Publisher: Elsevier BV

Date: 08-2000

DOI: 10.1016/S0021-9673(00)00613-0

Abstract: This work describes the separation of acidic, basic and neutral organic compounds as well as inorganic anions in a single run by capillary electrochromatography employing a stationary phase which exhibits both strong anion-exchange and reversed-phase chromatographic characteristics. The positive surface charge of this stationary phase provided a substantial anodic electroosmotic flow. The analytes were separated by a mixed-mode mechanism which comprised chromatographic interactions (hydrophobic interactions, ion-exchange) as well as electrophoretic migration. The influence of ion-exchange and hydrophobic interactions on the retention/migration of the analytes could be manipulated by varying the concentration of a competing ion and/or the amount of organic modifier present in the background electrolyte. Additionally the effects of pH changes on both the chromatographic interactions as well as the electrophoretic migration of the analytes were investigated.

Annexin A1 expression in a pooled breast cancer series: association with tumor subtypes and prognosis

Publisher: Springer Science and Business Media LLC

Date: 02-07-2015

DOI: 10.1186/S12916-015-0392-6

Zwitterionic-type hydrophilic interaction nano-liquid chromatography of complex and high mannose glycans coupled with electrospray ionisation high resolution time of flight mass spectrometry

Publisher: Elsevier BV

Date: 09-2011

DOI: 10.1016/J.CHROMA.2011.07.006

Abstract: In this study we describe a new method for rapid and sensitive analysis of reduced high mannose and complex glycans using zwitterionic-type hydrophilic interaction nano-liquid chromatography (nano ZIC-HILIC, 75 μm I.D.×150 mm) coupled with high resolution nanoelectrospray ionisation time of flight mass spectrometry (nano ESI-TOF-MS). The retention of neutral glycans increases with increasing molecular weight and is higher for high mannose glycans than for complex-type glycans. The selectivity of ZIC-HILIC for sialylated glycans differs from that for the neutral glycans and is believed to involve electrostatic repulsion therefore, charged glycans are eluted earlier than neutral glycans with comparable molecular weight. Due to the improved sensitivity achieved by employing a ZIC-HILIC nano-column, a range of less common complex glycans has been studied and the high resolution mass spectrometry enabled confirmation of glycan composition for the proposed structures. Good sensitivity for glycans was achieved without prior fluorescent labelling, and the time of the analysis was significantly reduced compared to the separation of glycans on a conventional-size column. The proposed method offers a fast and sensitive approach for glycan profiling applied to analysis of biopharmaceuticals.

Modelling of migration behaviour of inorganic anions in ion-exchange capillary electrochromatography

Publisher: Wiley

Date: 02-2001

DOI: 10.1002/1522-2683(200102)22:3<503::AID-ELPS503>3.0.CO;2-S

PEO-based brush-type amphiphilic macro-RAFT agents and their assembled polyHIPE monolithic structures for applications in separation science

Publisher: Springer Science and Business Media LLC

Date: 10-08-2017

DOI: 10.1038/S41598-017-08423-X

Abstract: Polymerized High Internal Phase Emulsions (PolyHIPEs) were prepared using emulsion-templating, stabilized by an hiphilic diblock copolymer prepared by reversible addition fragmentation chain transfer (RAFT) polymerization. The diblock copolymer consisted of a hydrophilic poly(ethylene glycol) methyl ether acrylate (PEO MA, average Mn 480) segment and a hydrophobic styrene segment, with a trithiocarbonate end-group. These diblock copolymers were the sole emulsifiers used in stabilizing “inverse” (oil-in-water) high internal phase emulsion templates, which upon polymerization resulted in a polyHIPE exhibiting a highly interconnected monolithic structure. The polyHIPEs were characterized by FTIR spectroscopy, BET surface area measurements, SEM, SEM-EDX, and TGA. These materials were subsequently investigated as stationary phase for high-performance liquid chromatography (HPLC) via in situ polymerization in a capillary format as a ‘column housing’. Initial separation assessments in reversed-phase (RP) and hydrophilic interaction liquid chromatographic (HILIC) modes have shown that these polyHIPEs are decorated with different microenvironments amongst the voids or domains of the monolithic structure. Chromatographic results suggested the existence of RP/HILIC mixed mode with promising performance for the separation of small molecules.

Understanding the interaction of gold and silver nanoparticles with natural organic matter using affinity capillary electrophoresis

Publisher: Royal Society of Chemistry (RSC)

Date: 2019

DOI: 10.1039/C9EN00014C

Abstract: Nanoparticles (NPs) undergo a number of changes in environmental systems which are often influenced by their interaction with natural organic matter (NOM).

Kinetic performance optimisation for liquid chromatography: Principles and practice

Publisher: Wiley

Date: 10-03-2011

DOI: 10.1002/JSSC.201000904

Abstract: This HPLC tutorial focuses on the preparation and use of kinetic plots to characterise the performance in isocratic and gradient LC. This graphical approach allows the selection of columns (i.e. optimum particle size and column length) and LC conditions (operating pressure and temperature) to generate a specific number of plates or peak capacity in the shortest possible analysis time. Instrument aspects including the influence of extra-column effects (maximum allowable system volume) and thermal operating conditions (oven type) on performance are discussed. In addition, the performance characteristics of porous-shell particle-packed columns and monolithic stationary phases are presented and the potential of future column designs is discussed.

Flow-dependent separation selectivity for organic molecules on metal-organic frameworks containing adsorbents

Publisher: Royal Society of Chemistry (RSC)

Date: 2016

DOI: 10.1039/C6CC00111D

Abstract: A new effect was discovered which allows changes of selectivity by variation of the mobile phase flow rate.

Recent developments and future possibilities for polymer monoliths in separation science

Publisher: Royal Society of Chemistry (RSC)

Date: 2012

DOI: 10.1039/C2AN35804B

Abstract: Within recent years there has been an increase in research focused on the design and application of organic polymer monoliths in all areas of separation science. This is largely driven by the theoretical and practical benefits that these materials should be able to provide, particularly in terms of improved biocompatibility and high permeability. This review summarises recent new developments in this field with a focus on new approaches to the design and synthesis of polymeric monolithic materials for analytical separation science. This includes the use of alternative synthetic methodologies such as the development of hyper-crosslinked monoliths, preparation of hybrid materials and incorporation of nanostructures in the polymeric scaffold. New and developing approaches for the structural characterisation of monolithic columns are also included. Finally, we critically discuss the current chromatographic performances achieved with this column technology as well as where future developments in this field may be directed.

Capillary electrophoretic separation of mono- and di-saccharides with dynamic pH junction and implementation in microchips

Publisher: Royal Society of Chemistry (RSC)

Date: 2010

DOI: 10.1039/C0AN00010H

Abstract: An electrophoretic method for the separation of derivatised mono- and di-saccharides with on-line concentration via dynamic pH junction has been developed and optimised in capillaries. Dynamic pH junction is perfectly suited for on-line concentration of derivatised sugars due to the acidic derivatisation conditions, however, most reagents for carbohydrates are not ionisable, requiring the use of the novel reagent, O-2-[aminoethyl]fluorescein. Optimisation of the separation selectivity yielded best separations with 170 mM ammonium borate buffer at pH 8.60 in an acrylamide coated capillary. When using an injection comprising 7% of the capillary volume and detection via laser induced fluorescence (LIF) with an argon ion laser, limits of detection as low as 0.13 nM for maltose were obtained, which was 10 times lower than could be achieved without on-line concentration. In order to implement this system in a glass/PDMS microchip, the low pH s le was introduced into the microchannels via a cathodic pH independent electro-osmotic flow (EOF) generated using a poly(dimethyldiallylmethyl-ammonium chloride) (PDADMAC) oly(styrene sulfonate) (PSS) polyelectrolyte multilayer coating. Optimisation of the injection volume in capillaries greatly simplified translation to the microchip platform, with the optimum capillary s le volume of 7%, dictating the use of an off-set cross with a volume 7% of the separation channel. Microchip separations of maltose, glucose, galactose and allose with dynamic pH junction, were achieved within 120 s, with the limit of detection of maltose using a light emitting diode induced fluorescence (LEDIF) detection system being 790 nM. This is 10 times lower than that achieved without concentration, and is lower than other reports of derivatised sugars using LEDIF detection. This is the first implementation of on-line concentration via a dynamic pH junction in a microchip, and significantly, the improvement in sensitivity achieved when translated to the microchip was equivalent to that achieved in capillaries.

Sensitive determination of carbohydrates labelled with p-nitroaniline by capillary electrophoresis with photometric detection using a 406 nm light-emitting diode

Publisher: Wiley

Date: 10-2006

DOI: 10.1002/ELPS.200500856

Abstract: p-Nitroaniline was explored as a derivatising reagent for UV absorbance detection of carbohydrates after separation by CE. This derivatising agent has three advantages: first, it has excellent water solubility second, it has high molar absorptivity and third, it is possible to obtain sensitive detection using a UV or blue light-emitting diode (LED) as the light source. The labelling reaction took less than 30 min to complete with high reaction yield. The separation process was modelled and optimised using an artificial neural network. Nine carbohydrates were separated by a CE system within 16 min using a 0.17 M boric acid buffer at pH 9.7. On-column LED detection at 406 nm allowed the detection of carbohydrates with good detection limits (<1.1 microM or 8.8 fmol) and reproducible quantification in the concentration range of 2.6-200 microM. This method was applied successfully to the determination of component carbohydrates in some food s les.

Polymeric stationary phases for size exclusion chromatography: a review

Publisher: Elsevier BV

Date: 03-2021

DOI: 10.1016/J.ACA.2021.338244

Glycan profiling of monoclonal antibodies using zwitterionic-type hydrophilic interaction chromatography coupled with electrospray ionization mass spectrometry detection

Publisher: Elsevier BV

Date: 2011

DOI: 10.1016/J.AB.2010.09.035

Abstract: We present a new method for the analysis of glycans enzymatically released from monoclonal antibodies (MAbs) employing a zwitterionic-type hydrophilic interaction chromatography (ZIC-HILIC) column coupled with electrospray ionization mass spectrometry (ESI-MS). Both native and reduced glycans were analyzed, and the developed procedure was compared with a standard HILIC procedure used in the pharmaceutical industry whereby fluorescent-labeled glycans are analyzed using a TSK Amide-80 column coupled with fluorescence detection. The separation of isobaric alditol oligosaccharides present in monoclonal antibodies and ribonuclease B is demonstrated, and ZIC-HILIC is shown to have good capability for structural recognition. Glycan profiles obtained with the ZIC-HILIC column and ESI-MS provided detailed information on MAb glycosylation, including identification of some less abundant glycan species, and are consistent with the profiles generated with the standard procedure. This new ZIC-HILIC method offers a simpler and faster approach for glycosylation analysis of therapeutic antibodies.

Dried blood spot sampling-A new approach for whole blood analysis

Publisher: CSIRO Publishing

Date: 2011

DOI: 10.1071/CH11141

On Track for a Truly Green Propolis-Fingerprinting Propolis Samples from Seven Countries by Means of a Fully Green Approach

Publisher: American Chemical Society (ACS)

Date: 19-10-2016

DOI: 10.1021/ACSSUSCHEMENG.6B02005

Development and optimization of an analytical method for the determination of UV filters in suntan lotions based on microemulsion electrokinetic chromatography

Publisher: Wiley

Date: 08-2002

DOI: 10.1002/1522-2683(200208)23:15<2424::AID-ELPS2424>3.0.CO;2-U

Effect of shearing stress on the radial heterogeneity and chromatographic performance of styrene-based polymerised high internal phase emulsions prepared in capillary format

Publisher: Royal Society of Chemistry (RSC)

Date: 2019

DOI: 10.1039/C8RA06188B

Abstract: The preparation of polymerised high internal phase emulsions with high shear in narrower capillary dimensions results in significant improvements in the chromatographic performance for the separation of proteins.

Styrene-based polymerised high internal phase emulsions using monomers in the internal phase as co-surfactants for improved liquid chromatography

Publisher: Royal Society of Chemistry (RSC)

Date: 2022

DOI: 10.1039/D1RA07705H

Abstract: Poly(styrene- co - inylbenzene)-based monoliths prepared from the polymerisation of water-in-monomer high internal phase emulsions, where water-soluble monomers acrylamide or poly(ethylene glycol) diacrylate ( M w 258) were included in internal phase.

Membrane assisted and temperature controlled on-line evaporative concentration for microfluidics

Publisher: Elsevier BV

Date: 02-2017

DOI: 10.1016/J.CHROMA.2016.12.003

Abstract: A membrane evaporation concentrator for continuous flow conditions is introduced. The membrane evaporation concentrator provides nearly 30-fold concentration in less than 60min whilst maintaining solute integrity under different sub-ambient pressure conditions and mild temperatures. To better understand the performance of the concentrator, a theoretical model was developed using caffeine as a model analyte, and used to predict the concentration performance of three target analytes at different conditions. An exponential relationship exists between temperature and concentration factor. By using the model it was determined that a 10-fold concentration (±0.5) can be performed at 56.72±0.07°C and at a flow rate of 10μLmin

Monolithic Phases for Ion Chromatography

Publisher: Annual Reviews

Date: 19-07-2011

DOI: 10.1146/ANNUREV-ANCHEM-061010-113929

Abstract: Monolithic media are continuing to increase in popularity in chromatographic applications, and the ongoing use of commercially available materials in ion chromatography (IC) has made monoliths a viable alternative to packed-bed columns for routine use. We discuss different strategies for the synthesis of polymeric and silica monoliths with ion-exchange functionality, such as direct incorporation of ion-exchange functionality during monolith preparation and different postpolymerization alterations such as grafting and coating. The formulations and strategies presented are focused on materials intended for use in IC. We also discuss strategies for materials characterization, with emphasis on nondestructive techniques for the characterization of monolith surface functionality, especially those with applicability to in situ analysis. Finally, we describe selected IC applications of polymeric and silica monoliths published from 2008 to 2010.

Simple and robust determination of monosaccharides in plant fibers in complex mixtures by capillary electrophoresis and high performance liquid chromatography

Publisher: Elsevier BV

Date: 05-2013

DOI: 10.1016/J.CHROMA.2013.03.041

Abstract: Carbohydrates partially liberated by acid hydrolysis of plant fiber can be separated by hydrophilic interaction liquid chromatography (HILIC), ligand-exchange liquid chromatography or other forms of LC with ion-exchange columns. However, the robust hydrogen-exchange columns show co-elution of galactose, xylose and mannose. Free solution capillary electrophoresis (CE) can be used without derivatization at pH 12.6 and was found to provide a higher resolution of galactose and xylose than common LC with no s le pre-treatment required, other than dilution, within 26min. CE was able to provide resolution higher than 0.79 for all separated carbohydrates, and the RSDs of determined concentrations lower than 10% for concentrations above 1.3gL(-1). A quantitative comparison between CE and HPLC revealed that up to 22% more carbohydrates are quantified with CE. Direct UV detection in CE of mono- and disaccharides is unexpectedly possible at 270nm. NMR analysis shows that alkaline degradation is too slow to explain this detection. This CE detection sensitivity is increased by the electric field and our CE and NMR analyses are consistent with a photo-oxidation process.

Identification of inorganic ions in post-blast explosive residues using portable CE instrumentation and capacitively coupled contactless conductivity detection

Publisher: Wiley

Date: 11-2008

DOI: 10.1002/ELPS.200800226

Abstract: Novel CE methods have been developed on portable instrumentation adapted to accommodate a capacitively coupled contactless conductivity detector for the separation and sensitive detection of inorganic anions and cations in post-blast explosive residues from homemade inorganic explosive devices. The methods presented combine sensitivity and speed of analysis for the wide range of inorganic ions used in this study. Separate methods were employed for the separation of anions and cations. The anion separation method utilised a low conductivity 70 mM Tris/70 mM CHES aqueous electrolyte (pH 8.6) with a 90 cm capillary coated with hexadimethrine bromide to reverse the EOF. Fifteen anions could be baseline separated in 7 min with detection limits in the range 27-240 microg/L. A selection of ten anions deemed most important in this application could be separated in 45 s on a shorter capillary (30.6 cm) using the same electrolyte. The cation separation method was performed on a 73 cm length of fused-silica capillary using an electrolyte system composed of 10 mM histidine and 50 mM acetic acid, at pH 4.2. The addition of the complexants, 1 mM hydroxyisobutyric acid and 0.7 mM 18-crown-6 ether, enhanced selectivity and allowed the separation of eleven inorganic cations in under 7 min with detection limits in the range 31-240 microg/L. The developed methods were successfully field tested on post-blast residues obtained from the controlled detonation of homemade explosive devices. Results were verified using ion chromatographic analyses of the same s les.

Coupled reversed-phase and ion chromatographic system for the simultaneous identification of inorganic and organic explosives

Publisher: Elsevier BV

Date: 05-2011

DOI: 10.1016/J.CHROMA.2011.03.046

Abstract: There are many methods available to detect and positively identify either organic or inorganic explosives separately, however no one method has been developed which can detect both types of explosive species simultaneously from a single s le. In this work, a unique coupled-chromatographic system is reported for the simultaneous determination of both organic and inorganic explosive species and is used for pre-blast analysis/identification purposes. This novel approach is based on the combination of reversed-phase high performance liquid chromatography and ion chromatography which allows trace levels of organic and inorganic explosives to be determined simultaneously from a single s le. Using this procedure, a 20 min reversed-phase separation of organic explosives is coupled to a 16 min ion-exchange separation of anions present in inorganic explosives, providing a complete pre-blast analysis/identification system for the separation and detection of a complex mixture containing organic and/or inorganic explosive species. The total analysis time, including sufficient column re-equilibration between runs, was <25 min using the coupled system. By this method, the minimum resolution for the organic separation was 1.16 between nitroglycerin and tetryl and the detection limits ranged from 0.31 mg L(-1) for cyclotetramethylene tetranitramine (HMX) and 1.54 mg L(-1) for pentaerythrite tetranitrate (PETN), while the minimum resolution for the inorganic separation was 0.99 between azide and nitrate, and the detection limits ranged from 7.70 μg L(-1) for fluoride and 159.50 μg L(-1) for benzoate.

Discovery of Biomarkers for Tasmanian Devil Cancer (DFTD) by Metabolic Profiling of Serum

Publisher: American Chemical Society (ACS)

Date: 23-09-2016

DOI: 10.1021/ACS.JPROTEOME.6B00629

Abstract: Devil facial tumor disease (DFTD) is a transmissible cancer threatening Tasmanian devils (Sarcophilus harrisii) with extinction. There is no preclinical test available for DFTD, and thus our aim was to find biomarkers for DFTD by metabolic fingerprinting. Seventy serum s les from wild Tasmanian devils (35 controls, 35 with tumors) were analyzed by liquid chromatography-high-resolution mass spectrometry. Features were selected by multivariate models (PLS/DA, random forests) comparing age-matched training set (n = 20 × 2) and further complying with fold-change threshold (≥1.4) and Mann-Whitney U-tests with correction for multiple hypotheses (false discovery rate (FDR) q 0.45, p < 0.01). Additional potential markers included amino acid and lipid metabolites, while cortisol and urea were the most significant health predictors (AUC ≥ 0.90). PLS/DA resulted in AUC = 0.997 for the training set and overall sensitivity of 91% and specificity of 97%. A support vector machine model utilizing only the major peptide marker and seven other metabolites led to overall 94% sensitivity and specificity. The novel findings in this first DFTD metabolomics study shed light on metabolic changes in Tasmanian devils affected by DFTD and provide a valuable step toward the development of prognostic biomarkers.

Effect of hydrophilic/lipophilic balance on the porogenic properties of non-ionic surfactants for monolith preparation and chromatographic separation

Publisher: Elsevier BV

Date: 06-2023

DOI: 10.1016/J.CHROMA.2023.463991

Identification of homemade inorganic explosives by ion chromatographic analysis of post-blast residues

Publisher: Elsevier BV

Date: 02-2008

DOI: 10.1016/J.CHROMA.2008.01.014

Abstract: Anions and cations of interest for the post-blast identification of homemade inorganic explosives were separated and detected by ion chromatographic (IC) methods. The ionic analytes used for identification of explosives in this study comprised 18 anions (acetate, benzoate, bromate, carbonate, chlorate, chloride, chlorite, chromate, cyanate, fluoride, formate, nitrate, nitrite, perchlorate, phosphate, sulfate, thiocyanate and thiosulfate) and 12 cations (ammonium, barium(II), calcium(II), chromium(III), ethylammonium, magnesium(II), manganese(II), methylammonium, potassium(I), sodium(I), strontium(II), and zinc(II)). Two IC separations are presented, using suppressed IC on a Dionex AS20 column with potassium hydroxide as eluent for anions, and non-suppressed IC for cations using a Dionex SCS 1 column with oxalic acid/acetonitrile as eluent. Conductivity detection was used in both cases. Detection limits for anions were in the range 2-27.4ppb, and for cations were in the range 13-115ppb. These methods allowed the explosive residue ions to be identified and separated from background ions likely to be present in the environment. Linearity (over a calibration range of 0.05-50ppm) was evaluated for both methods, with r(2) values ranging from 0.9889 to 1.000. Reproducibility over 10 consecutive injections of a 5ppm standard ranged from 0.01 to 0.22% relative standard deviation (RSD) for retention time and 0.29 to 2.16%RSD for peak area. The anion and cation separations were performed simultaneously by using two Dionex ICS-2000 chromatographs served by a single autoinjector. The efficacy of the developed methods was demonstrated by analysis of residue s les taken from witness plates and soils collected following the controlled detonation of a series of different inorganic homemade explosives. The results obtained were also confirmed by parallel analysis of the same s les by capillary electrophoresis (CE) with excellent agreement being obtained.

A green, simplified, and efficient experimental setup for a high-throughput screening of agri-food by-products – From polar to nonpolar metabolites in sugarcane solid residues

Publisher: Elsevier BV

Date: 12-2020

DOI: 10.1016/J.CHROMA.2020.461693

Characterization of large surface area polymer monoliths and their utility for rapid, selective solid phase extraction for improved sample clean up

Publisher: Elsevier BV

Date: 09-2015

DOI: 10.1016/J.CHROMA.2015.07.065

Abstract: While polymer monoliths are widely described for solid phase extraction (SPE), appropriate characterization is rarely provided to unravel the links between physical characteristics and observed advantages and disadvantages. Two known approaches to fabricate large surface area polymer monoliths with a bimodal pore structure were investigated. The first incorporated a high percentage of inyl benzene (PDVB) and the second explored hypercrosslinking of pre-formed monoliths. Adsorption of probe analytes anisole, benzoic acid, cinnamic acid, ibuprofen and cortisone were investigated using frontal analysis and the SPE performance was compared with particulate adsorbents. Frontal analysis of anisole described maximum adsorption capacities of 164mgg(-1) and 298mgg(-1) for hypercrosslinked and PDVB adsorbents, respectively. The solvated state specific surface area was calculated to be 341 and 518m(2)g(-1) respectively. BET revealed a hypercrosslinked surface area of 817m(2)g(-1), 2.5 times greater than in the solvated state. The PDVB BET surface area was 531m(2)g(-1), similar to the solvated state. Micropores of 1nm provided the enhanced surface area for hypercrosslinked adsorbents. PDVB displayed a pore size distribution of 1-6nm. Frontal analysis demonstrated the micropores present size exclusion for the larger probes. Recovery of anisole was determined by SPE using 0.4 and 1.0mLmin(-1). Recovery for PDVB remained constant at 90%±0.103 regardless of the extraction flow rate suggesting extraction performance is independent of flow rate. A more efficient s le purification of saccharin in urine was yielded by PDVB due to selective permeation of the small pores.

Separation of metal ions and metal-containing species by micellar electrokinetic capillary chromatography, including utilisation of metal ions in separations of other species

Publisher: Elsevier BV

Date: 09-1997

DOI: 10.1016/S0021-9673(97)00373-7

Reviews - Updates, insights, new topics

Publisher: Wiley

Date: 06-2012

DOI: 10.1002/JSSC.201270073

Towards high capacity latex-coated porous polymer monoliths as ion-exchange stationary phases

Publisher: Royal Society of Chemistry (RSC)

Date: 2006

DOI: 10.1039/B511398A

Abstract: The preparation of high capacity agglomerated monolithic ion-exchangers for capillary ion chromatography is described. Post-modification of reactive monoliths was investigated as an alternative to co-polymerisation of a suitable functional monomer with an overarching goal of increasing ion-exchange capacity. Direct sulfonation of poly styrene-co- inyl benzene monoliths using concentrated sulfuric acid or chlorosulfonic acid was unsuccessful even for monoliths containing as low as 8% crosslinker. In contrast, chemical transformation of reactive monoliths containing glycidyl methacrylate was used to increase the ion-exchange capacity by up to more than thirty-fold with ion exchange capacities of 14-29 microequiv g(-1) achieved. Three different reactions were considered, including reaction with 4-hydroxybenenesulfonic acid under basic conditions reaction with thiobenzoic acid followed by transformation to a reactive thiol and the subsequent oxidation to the sulfonic acid and direct sulfonation with sodium sulfite. Of these, the reaction with sodium sulfite resulted in the most significant increase in the capacity and the best separation performance. In the isocratic mode separation efficiencies of over 13,500 plates m(-1) were observed (for iodate). The separation of seven inorganic anions was also demonstrated using a hydroxide gradient.

Integrated Platform Addressing the Finger-Prick Blood Processing Challenges of Point-of-Care Electrical Biomarker Testing.

Publisher: American Chemical Society (ACS)

Date: 03-01-2022

DOI: 10.1021/ACS.ANALCHEM.1C04470

Abstract: Continued advances in label-free electrical biosensors pave the way to simple, rapid, cost-effective, high-sensitivity, and quantitative biomarker testing at the point-of-care setting that would profoundly transform healthcare. However, implementation in routine diagnostics is faced with significant challenges associated with the inherent requirement for biofluid s le processing before and during testing. We present here a simple yet robust autonomous finger-prick blood s le processing platform integrated with nanoscale field-effect transistor biosensors and demonstrate the feasibility of measuring the SARS-CoV-2 nucleocapsid protein. The 3D-printed platform incorporates a high-yield blood-to-plasma separation module and a delay valve designed to terminate the assay at a specific time. The platform is driven by hydrostatic pressure to efficiently and automatically dispense plasma and washing/measurement buffer to the nanosensors. Our model study demonstrates the feasibility of detecting down to 1.4 pg/mL of the SARS-CoV-2 nucleocapsid protein within 25 min and with only minimal operator intervention.

Development and application of polymeric monolithic stationary phases for capillary electrochromatography

Publisher: Elsevier BV

Date: 07-2004

DOI: 10.1016/J.CHROMA.2004.04.057

Abstract: Monolithic columns for capillary electrochromatography are receiving quite remarkable attention. This review summarizes results excerpted from numerous papers concerning this rapidly growing area with a focus on monoliths prepared from synthetic polymers. Both the simplicity of the in situ preparation and the large number of readily available chemistries make the monolithic separation media a vital alternative to capillary columns packed with particulate materials. Therefore, they are now a well-established stationary phase format in the field of capillary electrochromatography. A wide variety of synthetic approaches as well as materials used for the preparation of the monolithic stationary phases are presented in detail. The analytical potential of these columns is demonstrated with separations involving various families of compounds and different chromatographic modes.

Precise, accurate and user-independent blood collection system for dried blood spot sample preparation

Publisher: Springer Science and Business Media LLC

Date: 05-04-2018

DOI: 10.1007/S00216-018-0993-Y

Abstract: An accurate and precise 3 μL blood collection and dispensing system is presented for the preparation of dried blood spot (DBS) s les. Using end-to-end glass capillaries in conjugation with pre-punched DBS pads, a blood micro collection system was developed to eliminate the haematocrit dispersion, widely associated with DBS technology, while providing better levels of accuracy and precision during s le preparation. This methodology is compared to traditional micro-volume blood collection systems, such as a pipette and a digitally controlled analytical syringe. Results showed that % of recovery for the capillary methodology was closer to 100% across the three haematocrit (HCT) levels tested and when prepared by two users (98 to 100% for capillaries, 78 to 104% for pipette and 93 to 97% for digital syringe) attesting a higher accuracy. Additionally, by taking advantage of the capillary action mechanism to collect and dispense autonomously the desired volume of blood onto the DBS pad, coefficients of variation between two in iduals were significantly lower than with standard methodologies (capillaries-0.05 to 0.77%, pipette-12.71 to 18.53% and digital syringe-0.72 to 1.77%). This alternate aspiration and dispensing methodology could be used by different users without compromising accuracy or precision when handling low volumes of blood during the pre-analytical steps. Graphical abstract Comparison of novel capillary dispensing methodology for dried blood spot s le preparation with pipette and digital syringe methodologies through accuracy and precision measurements of caffeine.

Longitudinal On-Column Thermal Modulation for Comprehensive Two-Dimensional Liquid Chromatography

Publisher: American Chemical Society (ACS)

Date: 22-12-2017

DOI: 10.1021/ACS.ANALCHEM.6B03279

Abstract: Longitudinal on-column thermal modulation for comprehensive two-dimensional liquid chromatography is introduced. Modulation optimization involved a systematic investigation of heat transfer, analyte retention, and migration velocity at a range of temperatures. Longitudinal on-column thermal modulation was realized using a set of alkylphenones and compared to a conventional valve-modulator employing s le loops. The thermal modulator showed a reduced modulation-induced pressure impact than valve modulation, resulting in reduced baseline perturbation by a factor of 6 yielding a 6-14-fold improvement in signal-to-noise. A red wine s le was analyzed to demonstrate the potential of the longitudinal on-column thermal modulator for separation of a complex s le. Discrete peaks in the second dimension using the thermal modulator were 30-55% narrower than with the valve modulator. The results shown herein demonstrate the benefits of an active focusing modulator, such as reduced detection limits and increased total peak capacity.

Monolithic cryopolymers with embedded nanoparticles. I. Capillary liquid chromatography of proteins using neutral embedded nanoparticles

Publisher: Elsevier BV

Date: 2013

DOI: 10.1016/J.CHROMA.2012.10.068

Abstract: Rigid monolithic cryostructures were prepared in capillary format at sub-zero temperatures and used successfully in the separation of proteins by hydrophobic interaction chromatography (HIC). The polymerization mixture consisted of poly(ethyleneglycol) diacrylate (PEGDA) M(n)∼258 as the single monomer, a mixture of dioxane and water as the porogen and N,N,N',N'-tetramethylethylenediamine (TEMED) and ammonium persulfate (APS) as the initiator system. At sub-zero temperatures, the solvent mixture used as the porogen is frozen, leading to the formation of a polymeric structure templated by the solvent crystals that are formed. The optimization of the polymerization reaction was carried out by studying the influence of different reaction parameters including the temperature of the reaction, monomer concentration and solvent, on the porous characteristics of the polymers obtained. Separations were performed in HIC mode using 3 M ammonium sulfate in 0.1 M phosphate buffer, pH 6.9 to 0.1 M phosphate buffer, pH 6.9 over a 15 min gradient. The addition of neutral nanoparticles synthesized by mini-emulsion polymerization greatly improved the separation of the protein mixture, doubling the peak capacity of the control column without nanoparticles (from 7 to 17). Although the peak capacities and resolution values achieved were lower than those reported for conventional methacrylate monolithic columns, the use of this polymerization approach allows the preparation of polymeric structures which presented a more open porous structure and consequently exhibited significantly higher permeability than conventional polymer monoliths.

Anion-exchange capillary electrochromatography with indirect UV and direct contactless conductivity detection

Publisher: Wiley

Date: 05-2001

DOI: 10.1002/1522-2683(200105)22:7<1273::AID-ELPS1273>3.0.CO;2-U

Utility of Pathology Imagebase for standardisation of prostate cancer grading

Publisher: Wiley

Date: 05-03-2018

DOI: 10.1111/HIS.13471

Identification of areas of grading difficulties in prostate cancer and comparison with artificial intelligence assisted grading

Publisher: Springer Science and Business Media LLC

Date: 15-06-2020

DOI: 10.1007/S00428-020-02858-W

Abstract: The International Society of Urological Pathology (ISUP) hosts a reference image database supervised by experts with the purpose of establishing an international standard in prostate cancer grading. Here, we aimed to identify areas of grading difficulties and compare the results with those obtained from an artificial intelligence system trained in grading. In a series of 87 needle biopsies of cancers selected to include problematic cases, experts failed to reach a 2/3 consensus in 41.4% (36/87). Among consensus and non-consensus cases, the weighted kappa was 0.77 (range 0.68–0.84) and 0.50 (range 0.40–0.57), respectively. Among the non-consensus cases, four main causes of disagreement were identified: the distinction between Gleason score 3 + 3 with tangential cutting artifacts vs. Gleason score 3 + 4 with poorly formed or fused glands (13 cases), Gleason score 3 + 4 vs. 4 + 3 (7 cases), Gleason score 4 + 3 vs. 4 + 4 (8 cases) and the identification of a small component of Gleason pattern 5 (6 cases). The AI system obtained a weighted kappa value of 0.53 among the non-consensus cases, placing it as the observer with the sixth best reproducibility out of a total of 24. AI may serve as a decision support and decrease inter-observer variability by its ability to make consistent decisions. The grading of these cancer patterns that best predicts outcome and guides treatment warrants further clinical and genetic studies. Results of such investigations should be used to improve calibration of AI systems.

Identification of inorganic improvised explosive devices by analysis of postblast residues using portable capillary electrophoresis instrumentation and indirect photometric detection with a light-emitting diode

Publisher: American Chemical Society (ACS)

Date: 18-08-2007

DOI: 10.1021/AC0708792

Abstract: A commercial portable capillary electrophoresis (CE) instrument has been used to separate inorganic anions and cations found in postblast residues from improvised explosive devices (IEDs) of the type used frequently in terrorism attacks. The purpose of this analysis was to identify the type of explosive used. The CE instrument was modified for use with an in-house miniaturized light-emitting diode (LED) detector to enable sensitive indirect photometric detection to be employed for the detection of 15 anions (acetate, benzoate, carbonate, chlorate, chloride, chlorite, cyanate, fluoride, nitrate, nitrite, perchlorate, phosphate, sulfate, thiocyanate, thiosulfate) and 12 cations (ammonium, monomethylammonium, ethylammonium, potassium, sodium, barium, strontium, magnesium, manganese, calcium, zinc, lead) as the target analytes. These ions are known to be present in postblast residues from inorganic IEDs constructed from ammonium nitrate/fuel oil mixtures, black powder, and chlorate erchlorate/sugar mixtures. For the analysis of cations, a blue LED (470 nm) was used in conjunction with the highly absorbing cationic dye, chrysoidine (absorption maximum at 453 nm). A nonaqueous background electrolyte comprising 10 mM chrysoidine in methanol was found to give greatly improved baseline stability in comparison to aqueous electrolytes due to the increased solubility of chrysoidine and its decreased adsorption onto the capillary wall. Glacial acetic acid (0.7% v/v) was added to ensure chrysoidine was protonated and to enhance separation selectivity by means of complexation with transition metal ions. The 12 target cations were separated in less than 9.5 min with detection limits of 0.11-2.30 mg/L (calculated at a signal-to-noise ratio of 3). The anions separation system utilized a UV LED (370 nm) in conjunction with an aqueous chromate electrolyte (absorption maximum at 371 nm) consisting of 10 mM chromium(VI) oxide and 10 mM sodium chromate, buffered with 40 mM tris(hydroxymethyl)aminomethane at pH 8.05. All 15 target anions were baseline separated in less than 9 min with limits of detection ranging from 0.24 to 1.15 mg/L (calculated at a signal-to-noise ratio of 3). Use of the portable instrumentation in the field was demonstrated by analyzing postblast residues in a mobile laboratory immediately after detonation of the explosive devices. Profiling the ionic composition of the inorganic IEDs allowed identification of the chemicals used in their construction.

Preparation of inverse polymerized high internal phase emulsions using an amphiphilic macro-RAFT agent as sole stabilizer

Publisher: Royal Society of Chemistry (RSC)

Date: 2016

DOI: 10.1039/C5PY02012C

Abstract: Oil-in-water (‘inverse’) High Internal Phase Emulsions (HIPEs) have been prepared using an hiphilic macro-RAFT agent with toluene as the internal dispersed phase (∼80 vol%) and an aqueous monomer solution as the continuous phase.

Lab-on-a-Chip device with laser-patterned polymer electrodes for high voltage application and contactless conductivity detection

Publisher: Royal Society of Chemistry (RSC)

Date: 2012

DOI: 10.1039/C2CC33693F

Abstract: A laser-patterned microchip electrophoresis device with integrated polymer electrodes for DC high voltages and AC capacitively-coupled contactless conductivity detection was developed. Electrophoresis separations comparable to devices with metal electrodes were obtained, at approximately 20 times lower cost.

Indirect photometric detection of anions in nonaqueous capillary electrophoresis employing orange G as probe and a light-emitting diode-based detector

Publisher: Wiley

Date: 07-2008

DOI: 10.1002/ELPS.200800116

Abstract: A method based on indirect photometric detection (IPD) in CE employing a blue LED (473 nm) as a light source and the highly absorbing (478 nm) anionic dye, Orange G, as the probe ion was developed for the sensitive analysis of inorganic and organic anions. The use of nonaqueous solvents was examined as a simple way to reduce the adsorption of the dye onto the capillary wall and to thereby improve the baseline stability. The benefits of this approach were confirmed by experiments using BGEs in methanol (MeOH) and DMSO in which superior baselines were obtained relative to those achieved using aqueous electrolyte systems. A range of commercial LEDs was tested to improve the detection performance, with a difference of 25% in sensitivity being observed between the best and worst performing LED. The final system (4 mM Orange G, 0.05% w/v hydroxypropylcellulose (HPC), 20 mM triethanolamine (TEA) in pure MeOH) exhibited stable baselines and very low LODs (0.10-0.18 microM) for a test mixture comprising nine inorganic and organic anions. These values represent a two- to six-fold improvement over previous studies and the proposed method provides the most sensitive IPD method for the determination of anions using CE published to date. RSDs for ten replicates were in the ranges of 0.42-0.62% for migration time, 1.41-3.46% for peak area and 3.20-5.78% for peak height.

Retention behavior and selectivity of a latex nanoparticle pseudostationary phase for electrokinetic chromatography

Publisher: Wiley

Date: 02-2011

DOI: 10.1002/ELPS.201000470

Abstract: The retention characteristics and separation selectivity of a novel latex nanoparticle (NP) pseudostationary phase (PSP) for electrokinetic chromatography have been characterized. The anionic NPs have very low or no affinity for cationic solutes, but show significant interactions and retention based on hydrophobic interactions. Retention factors of alkyl-phenyl ketones increase linearly with the concentration of the NPs and have zero or near zero y-intercepts as expected for electrokinetic chromatography with non-micellar PSPs. The retention factors of these solutes and representative pharmaceuticals decrease logarithmically with increases in the concentration of ACN in the background electrolyte, as expected for reversed-phase retention. Linear solvation energy relationship analysis indicates that the NPs are less cohesive than would be expected for polymeric PSPs with similar structure but that the overall separation selectivity can be expected to be similar to polymer PSPs with similar backbone chemistry. The results indicate that the hydrophobic core of the NPs is non-cohesive and is highly accessible to solutes, whereas the ionic head groups are not as accessible and do not contribute substantially to retention or selectivity.

High temperature liquid chromatography of intact proteins using organic polymer monoliths and alternative solvent systems

Publisher: Elsevier BV

Date: 05-2010

DOI: 10.1016/J.CHROMA.2010.03.033

Abstract: Alternative approaches to conventional acetonitrile gradient methods for reversed-phase liquid chromatographic analysis of intact proteins have been investigated using commercial poly(styrene-co- inylbenzene) monolithic columns (Dionex ProSwift RP-2H and RP-4H). Alternative solvents to acetonitrile (2-propanol and methanol) coupled with elevated temperatures demonstrated complementary approaches to adjusting separation selectivity and reducing organic solvent consumption. Measurements of peak area at increasing isothermal temperature intervals indicated that only minor (<5%) decreases in detectable protein recovery occurred between 40 and 100 degrees C on the timescale of separation (2-5 min). The reduced viscosity of a 2-propanol/water eluent at elevated temperatures permitted coupling of three columns to increase peak production (peaks/min) by 16.5%. Finally, narrow-bore (1 mm i.d.) columns were found to provide a more suitable avenue to fast, high temperature (up to 140 degrees C) separations.

Characterization of polymer monoliths containing embedded nanoparticles by scanning transmission X-ray microscopy (STXM)

Publisher: American Chemical Society (ACS)

Date: 04-03-2014

DOI: 10.1021/AC403166U

Abstract: The structural and chemical homogeneity of monolithic columns is a key parameter for high efficiency stationary phases in liquid chromatography. Improved characterization techniques are needed to better understand the polymer morphology and its optimization. Here the analysis of polymer monoliths by scanning transmission X-ray microscopy (STXM) is presented for the first time. Poly(butyl methacrylate-co-ethyleneglycoldimethacrylate) [poly(BuMA-co-EDMA)] monoliths containing encapsulated inylbenzene (DVB) nanoparticles were characterized by STXM, which gives a comprehensive, quantitative chemical analysis of the monolith at a spatial resolution of 30 nm. The results are compared with other methods commonly used for the characterization of polymer monoliths [scanning electron microscopy (SEM), transmission electron microscopy (TEM), mercury porosimetry, and nitrogen adsorption]. The technique permitted chemical identification and mapping of the nanoparticles within the polymeric scaffold. Residual surfactant, which was used during the manufacture of the nanoparticles, was also detected. We show that STXM can give more in-depth chemical information for these types of materials and therefore lead to a better understanding of the link between polymer morphology and chromatographic performance.

Boronate functionalised polymer monoliths for microscale affinity chromatography

Publisher: Royal Society of Chemistry (RSC)

Date: 2006

DOI: 10.1039/B609051F

Abstract: Novel macroporous monolithic stationary phase materials suitable for microscale boronate affinity chromatography were developed.

Preparation of highly interconnected hydrophilic polymers from emulsion templates with improved mechanical properties

Publisher: Elsevier BV

Date: 05-2018

DOI: 10.1016/J.EURPOLYMJ.2018.02.002

Cyano bonded silica monolith—Development of an in situ modification method for analytical scale columns

Publisher: Elsevier BV

Date: 09-2010

DOI: 10.1016/J.CHROMA.2010.07.052

Abstract: This study investigates the synthesis and chromatographic behaviour of an analytical size cyanopropyl "cyano" bonded silica monolith. Surface modification was undertaken by treating a neat silica monolith with chloro(3-cyanopropyl)dimethyl silane in dry heptane over a two day period. The resulting monolith showed stability over the duration of the testing program that involved flushing the column with more than 2000 column volumes of mobile phase. Efficiency measurements before and after sylation verified that the integrity of the silica monolith itself was not affected by the modification process, the highest number of theoretical plates (N/m) using anisole was 81,650. A brief selectivity test was then undertaken to assess methylene selectivity and phenyl selectivity. Elemental analysis was used to determine the homogeneity of the carbon load throughout the monolithic bed, and was compared to two commercial C18 and one 'self' modified C18 silica monoliths. The development of the in situ modification is also discussed.

Fluorophores and chromophores for the separation of carbohydrates by capillary electrophoresis

Publisher: Humana Press

Date: 04-10-2011

DOI: 10.1007/978-1-60761-875-1_2

A protocol for fabrication of polymer monolithic capillary columns and tuning the morphology targeting high-resolution bioanalysis in gradient-elution liquid chromatography

Publisher: Wiley

Date: 28-07-2023

DOI: 10.1002/JSSC.202300439

Abstract: Polymer monolithic stationary phases are designed as a continuous interconnected globular material perfused by macropores. Like packed column, where separation efficiency is related to particle diameter, the efficiency of monoliths can be enhanced by tuning the size of both the microglobules and macropores. This protocol described the synthesis of poly(styrene‐ co ‐ inylbenzene) monolithic stationary phases in capillary column formats. Moreover, guidelines are provided to tune the macropore structure targeting high‐throughput and high‐resolution monolith chromatography. The versatility of these columns is exemplified by their ability to separate tryptic digests, intact proteins, and oligonucleotides under a variety of chromatographic conditions. The repeatability of the presented column fabrication process is demonstrated by the successful creation of 12 columns in three different column batches, as evidenced by the consistency of retention times (coefficients of variance [c.v.] = 0.9%), peak widths (c.v. = 4.7%), and column pressures (c.v. = 3.1%) across the batches.

Characterization of oligo(acrylic acid)s and their block co-oligomers

Publisher: Elsevier BV

Date: 11-2018

DOI: 10.1016/J.ACA.2018.05.030

Abstract: Oligo(acrylic acid), oligoAA are important species currently used industrially in the stabilization of paints and also for the production of self-assembled polymer structures which have been shown to have useful applications in analytical separation methods and potentially in drug delivery systems. To properly tailor the synthesis of oligoAA, and its block co-oligomers synthesized by Reversible-Addition Fragmentation chain Transfer (RAFT) polymerization to applications, detailed knowledge about the chemical structure is needed. Commonly used techniques such as Size Exclusion Chromatography (SEC) and Electrospray Ionization-Mass Spectrometry (ESI-MS) suffer from poor resolution and non-quantitative distributions, respectively. In this work free solution Capillary Electrophoresis (CE) has been thoroughly investigated as an alternative, allowing for the separation of oligoAA by molar mass and the RAFT agent end group. The method was then extended to block co-oligomers of acrylic acid and styrene. Peak capacities up to 426 were observed for these 1D CE separations, 10 times greater than what has been achieved for Liquid Chromatography (LC) of oligostyrenes. To provide a comprehensive insight into the chemical structure of these materials

Kinetic optimisation of open-tubular liquid-chromatography capillaries coated with thick porous layers for increased loadability

Publisher: Elsevier BV

Date: 11-2011

DOI: 10.1016/J.CHROMA.2011.09.047

Abstract: The kinetic optimisation of open-tubular liquid chromatography (OTLC) columns has been revisited by taking the thick-film effects for porous coatings on retention, column resistance, band broadening and mass loadability into account. Considering the most advantageous case (i.e. where the retentive layer allows for the same high internal diffusion coefficient as conventional porous particles), calculations show the need for the development of coating procedures leading to porous films filling up approximately 50-70% of the total column diameter. Furthermore, to achieve optimum kinetic performance for separations of small molecules with total analysis times of less than 8h (k'=9), total column diameters should be less than 6 μm with lengths typically greater than 0.8m for N values of 125,000-500,000 at a pressure of 400 bar. The use of elevated temperature LC (90°C) is also shown to increase the allowable total column diameter to up to 9 μm for a larger range of N values (100,000-880,000).

Development of a novel fluorescent tag O-2-[aminoethyl]fluorescein for the electrophoretic separation of oligosaccharides

Publisher: Elsevier BV

Date: 03-2010

DOI: 10.1016/J.ACA.2010.01.011

Abstract: This study describes the development of a novel fluorescent tag, O-2-[aminoethyl]fluorescein, for the separation of sugars by capillary electrophoresis with fluorescence detection using an argon ion laser. The tag was synthesised using three consecutive steps namely: esterification, alkylation and hydrolysis, specifically designed to offer a flexible way in which to make an assortment of fluorescent tags from cheap and readily available starting reagents (typically less than $1 per g of fluorescent tag). Via this flexible synthetic pathway, O-2-[aminoethyl]fluorescein was designed and synthesised with a spacer group to lower steric effects between the fluorescein backbone and the reducing end of the carbohydrate which were anticipated to improve the reactivity of the tag. The newly synthesised tag, O-2-[aminoethyl]fluorescein was evaluated against structurally similar commercial fluorescent motifs namely fluorescent 5-aminomethylfluorescein and non-fluorescent 5-aminofluorescein. Kinetic studies indicated that O-2-[aminoethyl]fluorescein showed similar labeling efficiencies as 5-aminomethylfluorescein, but were achieved in only 30 min, supporting the notion of improved reactivity of the spacer group. The sensitivity of O-2-[aminoethyl]fluorescein was evaluated using maltoheptaose with a detection limit of 1 nM obtained, which was slightly higher than that of 0.3 nM obtained with 5-aminomethylfluorescein, and was due to its lower quantum yield (0.24) when conjugated to the sugar. The separation performance of the tag was also benchmarked with the two commercial reagents using a range of corn syrup oligosaccharides, from 4 to 10 glucose units, typically found in rice starch. Separations were performed using an electrolyte containing 100 mM boric acid, tris at pH 8.65 as background electrolyte, 30 kV applied voltage, 50 microm I.D. x 40 cm (30 cm effective length) capillary. The novel tag showed better resolution of small oligosaccharides, G3 and G4, than the other two reagents, but slightly worse resolution for the longer oligosaccharides, most likely due to the monovalent charge state of the O-2-[aminoethyl]fluorescein compared to the alent charge of the other two tags.

RAD51B in Familial Breast Cancer

Publisher: Public Library of Science (PLoS)

Date: 05-05-2016

DOI: 10.1371/JOURNAL.PONE.0153788

Photografting and the Control of Surface Chemistry in Three-Dimensional Porous Polymer Monoliths

Publisher: American Chemical Society (ACS)

Date: 02-2003

DOI: 10.1021/MA021351W

The development of the in situ modification of 1st generation analytical scale silica monoliths

Publisher: Springer Science and Business Media LLC

Date: 26-03-2014

DOI: 10.1007/S10337-014-2667-Z

Controlling the surface chemistry and chromatographic properties of methacrylate-ester-based monolithic capillary columnsviaphotografting

Publisher: Wiley

Date: 02-2007

DOI: 10.1002/JSSC.200600316

Abstract: Preparation of monolithic capillary columns for separations in the CEC mode using UV-initiated polymerization of the plain monolith followed by functionalization of its pore surface by photografting has been studied. The first step enabled the preparation of generic poly(butyl methacrylate-co-ethylene dimethacrylate) monoliths with optimized porous properties, controlled by the percentages of porogens 1-decanol and cyclohexanol in the polymerization mixture, irradiation time, and UV light intensity. Ionizable monomers [2-(methacryloyloxy)ethyl]trimethylammonium chloride or 2-acryloamido-2-methyl-1-propanesulfonic acid were then photografted onto the monolithic matrix, allowing us to control the direction of the EOF in CEC. Different strategies were applied to control the grafting density and, thereby, the magnitude of the EOF. To control the hydrophobic properties, two approaches were tested: (i) cografting of a mixture of the ionizable and hydrophobic monomers and (ii) sequential grafting of the ionizable and hydrophobic monomers. Cografting resulted in similar retention but higher EOF. With sequential grafting, more than 50% increase in retention factors was obtained and a slight decrease in EOF was observed due to shielding of the ionizable moieties.

Valve based on novel hydrogels: From synthesis to application

Publisher: Elsevier BV

Date: 11-2013

DOI: 10.1016/J.SNB.2013.06.086

Acetone as a greener alternative to acetonitrile in liquid chromatographic fingerprinting

Publisher: Wiley

Date: 02-04-2015

DOI: 10.1002/JSSC.201401324

Abstract: A considerable amount of chemical waste from liquid chromatography analysis is generated worldwide. Acetonitrile is the most employed solvent in liquid chromatography analyses since it exhibits favorable physicochemical properties for separation and detection, but it is an unwelcome solvent from an environmental point of view. Acetone might be a much greener alternative to replace acetonitrile in reversed-phase liquid chromatography, since both share similar physicochemical properties, but its applicability with ultraviolet absorbance-based detectors is limited. In this work, a reference method using acetonitrile and high-performance liquid chromatography coupled to an ultraviolet photodiode array detector coupled to a corona charged aerosol detector system was developed to fingerprint a complex s le. The possibility of effectively substituting acetonitrile with acetone was investigated. Design of experiments was adopted to maximize the number of peaks acquired in both fingerprint developments. The methods with acetonitrile or acetone were successfully optimized and proved to be statistically similar when only the number of peaks or peak capacity was taken into consideration. However, the superiority of the latter was evidenced when parameters of separation and those related to greenness were heuristically combined. A green, comprehensive, time- and resource-saving approach is presented here, which is generic and applicable to other complex matrices. Furthermore, it is in line with environmental legislation and analytical trends.

Photolithographic patterning of conducting polyaniline films via flash welding

Publisher: Elsevier BV

Date: 07-2010

DOI: 10.1016/J.SYNTHMET.2010.04.018

A simple capillary electrophoresis method for the rapid separation and determination of intact low molecular weight and unfractionated heparins

Publisher: Elsevier BV

Date: 2008

DOI: 10.1016/J.JPBA.2007.10.009

Abstract: A simple, selective and accurate capillary electrophoresis (CE) method has been developed for the rapid separation and identification of various low molecular weight heparins (LMWHs) and unfractionated heparin. Separation and operational parameters were investigated using dalteparin sodium as the test LMWH. The developed method used a 70 cm fused silica capillary (50 microm i.d.) with a detection window 8.5 cm from the distal end. Phosphate electrolyte (pH 3.5 50 mM), an applied voltage of -30 k V, UV detection at 230 nm and s le injection at 20 mbar for 5s were used. The method performance was assessed in terms of linearity, selectivity, intra- and inter-day precision and accuracy. The method was successfully applied to the European Pharmacopeia LMWH standard, dalteparin sodium, enoxaparin sodium and heparin sodium with a significant reduction in the run time and increased resolution compared with previously reported CE methods. Different CE separation profiles were obtained for various LMWHs and unfractionated heparin showing significant structural ersity. The current methodology was sensitive enough to reveal minor constituent differences between two different batches of enoxaparin sodium. This CE method also clearly showed chemical changes that occurred to LMWHs under different stress conditions. The sensitivity, selectivity and simplicity of the developed method allow its application in research or manufacturing for the identification, stability analysis, characterization and monitoring of batch-to-batch consistency of different low molecular weight and unfractionated heparins.

Macroporous monolith supports for continuous flow capillary microreactors

Publisher: Elsevier BV

Date: 12-2006

DOI: 10.1016/J.TETLET.2006.10.113

Natural deep eutectic solvents as the major mobile phase components in high-performance liquid chromatography—searching for alternatives to organic solvents

Publisher: Springer Science and Business Media LLC

Date: 12-04-2018

DOI: 10.1007/S00216-018-1027-5

Abstract: Over the past six decades, acetonitrile (ACN) has been the most employed organic modifier in reversed-phase high-performance liquid chromatography (RP-HPLC), followed by methanol (MeOH). However, from the growing environmental awareness that leads to the emergence of "green analytical chemistry," new research has emerged that includes finding replacements to problematic ACN because of its low sustainability. Deep eutectic solvents (DES) can be produced from an almost infinite possible combinations of compounds, while being a "greener" alternative to organic solvents in HPLC, especially those prepared from natural compounds called natural DES (NADES). In this work, the use of three NADES as the main organic component in RP-HPLC, rather than simply an additive, was explored and compared to the common organic solvents ACN and MeOH but additionally to the greener ethanol for separating two different mixtures of compounds, one demonstrating the elution of compounds with increasing hydrophobicity and the other comparing molecules of different functionality and molar mass. To utilize NADES as an organic modifier and overcome their high viscosity monolithic columns, temperatures at 50 °C and 5% ethanol in the mobile phase were used. NADES are shown to give chromatographic performances in between those observed for ACN and MeOH when eluotropic strength, resolution, and peak capacity were taken into consideration, while being less environmentally impactful as shown by the HPLC-Environmental Assessment Tool (HPLC-EAT) metric. With the development of proper technologies, DES could open a new class of mobile phases increasing the possibilities of new separation selectivities while reducing the environmental impact of HPLC analyses. Graphical abstract Natural deep eutectic solvents versus traditional solvents in HPLC.

A simplified approach to direct SPE‐MS

Publisher: Wiley

Date: 09-2012

DOI: 10.1002/JSSC.201200466

Abstract: Microextraction by packed sorbent (MEPS) has been directly hyphenated with ESI-MS for the rapid screening of opiates and codeine metabolites in urine. This study introduces a novel format of MEPS that incorporates a two-way valve in the barrel of the syringe enabling the direction of liquid flow to be manipulated. Controlled directional flow (CDF) MEPS allows sharp, concentrated s le bands to be delivered directly to the MS in small volumes and effectively eliminates the need to optimize elution. The method optimization assessed the recovery, matrix effects, and the speed of infusion, all critical variables for optimum ESI performance. Matching extraction workflows demonstrated a reduction in carryover from 65% for conventional MEPS to only 1% for CDF MEPS. The recovery (<89% for 50 μL s le), matrix effects ( 0.99), and LODs (<5 ng/mL) were determined to demonstrate method performance. The optimized approach was employed for the screening of codeine metabolites in urine. The ion trace revealed sharp s le bands corresponding to the codeine metabolites. At-line MEPS-ESI-MS allowed both s le preparation and analysis to be completed in only 5 min facilitating high throughput and alleviating the burden of method development.

The Retention Characteristics of a Novel Phenyl Analytical Scale First Generation Monolith

Publisher: Informa UK Limited

Date: 04-11-2014

DOI: 10.1080/10826076.2014.968665

UiO-66@SiO2 core–shell microparticles as stationary phases for the separation of small organic molecules

Publisher: Royal Society of Chemistry (RSC)

Date: 2017

DOI: 10.1039/C6AN02344D

Abstract: Microparticles decorated with metal–organic frameworks exhibited a unique flow-dependent separation selectivity (FDSS) effect for the isocratic separation of small molecules.

Porous polymer monoliths for extraction: Diverse applications and platforms

Publisher: Wiley

Date: 06-2008

DOI: 10.1002/JSSC.200800116

Abstract: Polymer monoliths are becoming increasingly popular as sorbent materials, and, along with silica monoliths, they are sometimes touted as replacements for the particulate stationary phases used in HPLC. This critical and prospective review shows how polymer monoliths are in fact finding numerous extraction roles that do not resemble HPLC. They are showing great promise as extractors in a remarkable range of platforms, formats and hyphenated systems with functions ranging from chromatographic preconcentration to large-scale preparative extraction. Monolith surface chemistry, morphology and the approaches to monolith synthesis are discussed with regards to these emerging roles.

Distinct urinary glycoprotein signatures in prostate cancer patients

Publisher: Impact Journals, LLC

Date: 04-09-2018

DOI: 10.18632/ONCOTARGET.26005

Characterization of Wear Mechanisms of Silicon Carbide Materials

Publisher: Trans Tech Publications Ltd

Date: 27-10-2010

DOI: 10.4028/WWW.SCIENTIFIC.NET/AST.64.49

Identification of inorganic improvised explosive devices using sequential injection capillary electrophoresis and contactless conductivity detection

Publisher: American Chemical Society (ACS)

Date: 10-11-2011

DOI: 10.1021/AC2020195

Abstract: A simple sequential injection capillary electrophoresis (SI-CE) instrument with capacitively coupled contactless conductivity detection (C(4)D) has been developed for the rapid separation of anions relevant to the identification of inorganic improvised explosive devices (IEDs). Four of the most common explosive tracer ions, nitrate, perchlorate, chlorate, and azide, and the most common background ions, chloride, sulfate, thiocyanate, fluoride, phosphate, and carbonate, were chosen for investigation. Using a separation electrolyte comprising 50 mM tris(hydroxymethyl)aminomethane, 50 mM cyclohexyl-2-aminoethanesulfonic acid, pH 8.9 and 0.05% poly(ethyleneimine) (PEI) in a hexadimethrine bromide (HDMB)-coated capillary it was possible to partially separate all 10 ions within 90 s. The combination of two cationic polymer additives (PEI and HDMB) was necessary to achieve adequate selectivity with a sufficiently stable electroosmotic flow (EOF), which was not possible with only one polymer. Careful optimization of variables affecting the speed of separation and injection timing allowed a further reduction of separation time to 55 s while maintaining adequate efficiency and resolution. Software control makes high s le throughput possible (60 s les/h), with very high repeatability of migration times [0.63-2.07% relative standard deviation (RSD) for 240 injections]. The separation speed does not compromise sensitivity, with limits of detection ranging from 23 to 50 μg·L(-1) for all the explosive residues considered, which is 10× lower than those achieved by indirect absorbance detection and 2× lower than those achieved by C(4)D using portable benchtop instrumentation. The combination of automation, high s le throughput, high confidence of peak identification, and low limits of detection makes this methodology ideal for the rapid identification of inorganic IED residues.

Poly(tetrafluoroethylene) separation capillaries for capillary electrophoresis

Publisher: Elsevier BV

Date: 06-2004

DOI: 10.1016/J.CHROMA.2004.03.074

Abstract: Poly(tetrafluoroethylene) (PTFE) is a material widely known for its inertness and excellent electrical properties. It is also transparent in the UV region and has a reasonable thermal conductivity. These properties make PTFE a suitable material for the separation capillary in capillary electrophoresis. Differences in the chemistry of the capillary wall compared to fused silica (FS) can make PTFE an interesting alternative to FS for some special applications. In this work, properties of a commercial PTFE capillary of approx. 100 microm i.d. were investigated, including the dependence of electroosmotic flow (EOF) on pH for unmodified and dynamically modified PTFE, optical properties, and practical aspects of use. The main problems encountered for the particular PTFE capillary used in this study were that it was mechanically too soft for routine usage and the crystallinity of the PTFE caused light scattering, leading to high background absorbance values in the low UV region. The profile of the EOF versus pH for bare PTFE surprisingly showed significantly negative EOF values at pH < 4.2, with an EOF of -30 x 10(-9) m2 V(-1) s(-1) being observed at pH 2.5. This is likely to be caused by either impurities or additives of basic character in the PTFE, so that after their protonation at acidic pH they establish a positive charge on the capillary wall and create a negative EOF. A stable cationic semi-permanent coating of poly(diallyldimethylammonium chloride) (PDDAC) could be established on the PTFE capillary and led to very similar magnitudes of EOF to those observed with FS. A hexadecanesulfonate coating produced a cathodic EOF of extremely high magnitude ranging between +90 and +110 x 10(-9) m2 s(-1) V(-1), which are values high enough to allow counter-EOF separation of high mobility inorganic anions. In addition, pH-independent micellar electrokinetic capillary chromatography (MEKC) separations could be easily realised due to hydrophobic adsorption of sodium dodecylsulfate (used to form the micelles) on the wall of the PTFE capillary. The use of polymers that would be mechanically more robust and optically transparent in the low-UV region should make such CE capillaries an interesting alternative to fused silica.

Determination of inorganic anions by capillary electrochromatography

Publisher: Elsevier BV

Date: 06-2001

DOI: 10.1016/S0165-9936(01)00073-5

Monolithic stationary phases for fast ion chromatography and capillary electrochromatography of inorganic ions

Publisher: Wiley

Date: 08-2006

DOI: 10.1002/JSSC.200600169

Abstract: The focus of this review is on current developments in monolithic stationary phases for the fast analysis of inorganic ions and other small molecules in ion chromatography (IC) and capillary electrochromatography (CEC), concentrating in particular on the properties of organic (polymer) monolithic materials in comparison to inorganic (silica-based) monoliths. The applicability of these materials for fast IC is discussed in the context of recent publications, including the range of synthesis and modification procedures described. While commercial monolithic silica columns already show promising results on current IC instrumentation, polymer-based monolithic stationary phases are currently predominantly used in the capillary format on modified micro-IC systems. However, they are beginning to find application in IC particularly under high pH conditions, with the potential to replace their particle-packed counterparts.

Manufacturing and application of a fully polymeric electrophoresis chip with integrated polyaniline electrodes

Publisher: Royal Society of Chemistry (RSC)

Date: 2010

DOI: 10.1039/C003333B

Abstract: This work describes the development of a fully polymeric microchip with integrated polymeric electrodes suitable for performing microchip electrophoresis. The polymer electrodes were fabricated in a thin film of the conducting polymer, polyaniline (PANI), by flash lithography using a studio camera flash and a transparency mask. During flash welding, exposed regions welded into non-conducting regions forming a conducting polymer circuit in the non-exposed regions. Using a structured layer of dry film photoresist for sealing, a polydimethylsiloxane (PDMS) substrate containing channels and reservoirs was bound to the PANI film to form an integrated microfluidic device. The conducting regions of the PANI film were shown to be capable of carrying the high voltages of up to 2000 V required for chip electrophoresis, and were stable for up to 30 minutes under these conditions. The PANI electrodes were used for the electrophoretic separation of three sugars labelled with 8-amino-1,3,6-pyrenetrisulfonic acid (APTS) in the dry film resist-PDMS hybrid device. Highly efficient separations comparable to those achieved in similar microchips using platinum electrodes confirm the potential of polyaniline as a new material suitable for high voltage electrodes in Lab-on-a-chip devices.

Morphology control in polymerised high internal phase emulsion templated via macro-RAFT agent composition: visualizing surface chemistry

Publisher: Royal Society of Chemistry (RSC)

Date: 2018

DOI: 10.1039/C7PY01770G

Abstract: A series of polymerized high internal phase emulsion (polyHIPE) materials have been prepared by using a water in oil emulsion stabilized by a macro-RAFT agent, 2-(butylthiocarbonothioylthio)-2-poly(styrene)- b -poly(acrylic acid), acting as a polymeric surfactant.

Poly(ethylene glycol) functionalization of monolithic poly(divinyl benzene) for improved miniaturized solid phase extraction of protein-rich samples

Publisher: Springer Science and Business Media LLC

Date: 11-01-2017

DOI: 10.1007/S00216-016-0164-Y

Abstract: Non-specific protein adsorption on hydrophobic solid phase extraction (SPE) adsorbents can reduce the efficacy of purification. To improve s le clean-up, poly( inyl benzene) (PDVB) monoliths grafted with hydrophilic polyethylene glycol methacrylate (PEGMA) were developed. Residual vinyl groups (RVGs) of the PDVB were employed as anchor points for PEGMA grafting. Two PEGMA monomers, M

Utilisation of pH stacking in conjunction with a highly absorbing chromophore, 5-aminofluorescein, to improve the sensitivity of capillary electrophoresis for carbohydrate analysis

Publisher: Elsevier BV

Date: 07-2008

DOI: 10.1016/J.CHROMA.2008.04.022

Abstract: This study explores the use of pH stacking in conjunction with 5-aminofluorescein as a derivatization agent for the sensitive analysis of simple sugars such as glucose, lactose and maltotriose by capillary electrophoresis (CE). The derivatization agent was selected on the basis of its extremely high molar absorptivity, its compatibility with a 488nm light-emitting diode (LED) and the fact that it has two ionizable groups making it compatible with on-line stacking using a dynamic pH junction. The influence of both acetic and formic acids at concentrations of 0.19, 0.019 and 0.0019molL(-1) were investigated with regard to both derivatization efficiency and the ability to stack using a dynamic pH junction. Superior sensitivity and resolution was obtained in formic acid over acetic acid. Substantially lower peaks were obtained with 0.19molL(-1) formic acid when compared to 0.019 and 0.0019molL(-1) concentrations, which was confirmed by computer simulation studies to be due to the inadequate movement of the pH boundary for stacking. Further simulation studies combined with experimental data showed the separation with the best resolution and greatest sensitivity when the carbohydrates were derivatized with the 0.095molL(-1) formic acid. Utilisation of stacking via dynamic pH junction mode in conjunction with LED detection enabled efficiencies of 150,000 plates and detection limits in the order of 8.5x10(-8)molL(-1) for simple sugars such as glucose, lactose and maltotriose hydrate. The current system also demonstrates a 515 times improvement in sensitivity when compared to using a normal deuterium l , and 16 times improvement over other systems using LEDs.

Comparison of ZIC-HILIC and graphitized carbon-based analytical approaches combined with exoglycosidase digestions for analysis of glycans from monoclonal antibodies

Publisher: Elsevier BV

Date: 12-2012

DOI: 10.1016/J.JCHROMB.2012.10.043

Abstract: Two LC approaches for analysis of therapeutic monoclonal antibodies (MAbs) are presented and compared. In the first approach, zwitterionic-type hydrophilic interaction chromatography (ZIC-HILIC) of 2-aminobenzamide-labelled glycans was coupled with fluorescence or electrospray ionisation mass spectrometric (ESI-MS) detection. The ZIC-HILIC method enabled relative quantification and identification of major glycan species. The sensitivity of fluorescence detection was higher compared to ESI-MS however, MS detection enabled identification of co-eluted peaks. The new ZIC-HILIC approach was compared with porous graphitized carbon (PGC) separation of reduced glycans coupled with ESI-MS. Using PGC higher sensitivity was achieved compared to ZIC-HILIC due to the lower chemical background originating from the mobile phase and the derivatisation step, providing detailed information on minor glycan species. Furthermore, PGC exhibited excellent capability for separation of isobaric glycans with various degrees of mannosylation and galactosylation. The structures of glycans from MAbs used in this study were confirmed by exoglycosidase digestions. The two methods were applied to two monoclonal antibodies expressed in Chinese Hamster ovary cell lines and a monoclonal antibody expressed in a murine NS0 cell line. While the fluorescence-based approach is more suitable for routine glycan profiling due to the simplicity of data analysis, MS-based approaches were shown to provide detailed glycosylation analysis of complex glycoprotein s les.

International society of urological pathology (ISUP) grading of prostate cancer

Publisher: Ovid Technologies (Wolters Kluwer Health)

Date: 06-2016

DOI: 10.1097/PAS.0000000000000642

Simple and robust monitoring of ethanol fermentations by capillary electrophoresis

Publisher: Wiley

Date: 27-09-2013

DOI: 10.1002/BAB.1269

Abstract: Free-solution capillary electrophoresis (CE), or capillary zone electrophoresis, with direct UV detection was used for the first time for the determination of mono- and disaccharides, sugar alcohols, and ethanol in fermentation broths. S le preparation proved to be minimal: no derivatization or specific s le purification was needed. The CE conditions can be adapted to the type of fermentation by simply altering the background electrolyte (BGE). KOH (130 mM) or NaOH (130 mM) as the BGE led to the fastest analysis time when monitoring simple fermentations. A mixture of 65 mM NaOH and 65 mM LiOH led to a 19% improvement in resolution for a complex mixture of carbohydrates. Quantification of a simple carbohydrate fermentation by CE showed values in close agreement with that of high-performance anion exchange chromatography and high-performance liquid chromatography (HPLC) on a cation exchange resin. For complex fermentations, quantification of carbohydrates by HPLC and CE led to similar results, whereas CE requires an injection volume of only 10-20 nL. Analysis of an ethanol fermentation of hydrolyzed plant fiber demonstrated the robustness of the separation and detection of carbohydrates, as well as ethanol. Ethanol determination is achieved by coupling the CE method to pressure mobilization, using the same instrument and the same s le.

An answer in the palm of your hand: microfluidics for analytical applications

Publisher: SPIE

Date: 25-01-2003

DOI: 10.1117/12.480775

Kinetic performance appraisal of poly(styrene-co-divinylbenzene) monolithic high-performance liquid chromatography columns for biomolecule analysis

Publisher: Elsevier BV

Date: 06-2010

DOI: 10.1016/J.CHROMA.2010.04.007

Abstract: A broad appraisal of the kinetic performance of organic polymeric monolithic columns is reported using commercially available poly(styrene-co- inylbenzene) monolithic columns (Dionex ProSwift RP-1S). Analysis of a protein digest s le at elevated temperatures (> or =80 degrees C) indicated no apparent analyte degradation using an inert polymeric stationary phase. Comparison between low molecular weight solute and peptide separations highlighted the markedly different mass transport processes observed on macroporous monolithic beds and an improved C term at elevated temperature in both instances. The current usefulness of this column format for biomolecule analysis was further studied via employment of a kinetic performance characterisation for the first time to provide direction for column development servicing this application.

The development of microfluidic-based western blotting: Technical advances and future perspectives

Publisher: Elsevier BV

Date: 02-2023

DOI: 10.1016/J.CHROMA.2023.463813

Polymeric monolithic stationary phases for capillary electrochromatography

Publisher: Wiley

Date: 12-2002

DOI: 10.1002/ELPS.200290011

Abstract: This review summarizes the contributions of a number of groups working in the rapidly growing area of monolithic columns for capillary electrochromatography (CEC), with a focus on those prepared from synthetic polymers. Monoliths have quickly become a well‐established stationary phase format in the field of CEC. The simplicity of their in situ preparation method as well as the good control over their porous properties and surface chemistries make the monolithic separation media an attractive alternative to capillary columns packed with particulate materials. A wide variety of approaches as well as materials used for the preparation of the monolithic stationary phases are detailed. Their excellent chromatographic performance is demonstrated by numerous separations of different analytes.

High temperature liquid chromatography with monolithic capillary columns and pure water eluent

Publisher: Royal Society of Chemistry (RSC)

Date: 2009

DOI: 10.1039/B815886J

Abstract: Use of an organic polymeric monolithic stationary phase for high temperature liquid chromatography (HTLC) with a pure water eluent is demonstrated for the first time. Separations of n-alcohols at temperatures exceeding 200 degrees C were achieved with no statistically significant reduction in chromatographic performance evident after continuous operation for 1000 column volumes above 200 degrees C.

Characterization of monoclonal antibodies using polymeric cation exchange monoliths in combination with salt and pH gradients

Publisher: Wiley

Date: 08-2009

DOI: 10.1002/JSSC.200900283

Abstract: The characterization of three different mAb formulations of pharmaceutical interest is demonstrated using cation exchange polymethacrylate‐based monolithic columns as well as imaged CE (iCE). Elution of the mAbs from both a strong cation exchanger (ProSwift TM SCX‐1S) and a weak cation exchanger (ProSwift WCX‐1S) was readily achieved employing a linear salt gradient or a mixed buffer pH gradient indicating that either approach can be used in purification or isolation. Using a linear salt gradient, the elution profile on the two types of exchangers was found to differ indicating that the combination of both strong and weak ion exchangers is needed for complete characterization. The elution profile of two of the mAbs on the strong cation exchanger used in combination with a linear pH gradient from pH 4 to 10 showed signs of charge heterogeneity. The use of iCE was found to be the best choice for characterization of charge heterogeneity, showing a clear charge distribution for all three mAbs.

University Of South Australia

Location: Australia

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Johannes Kepler Universitat Linz

Location: Austria

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E O Lawrence Berkeley National Laboratory

Location: United States of America

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University Of Tasmania

Location: Australia

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Hyphenated Capillary Electrophoresis - Mass Spectrometry Facility

Start Date: 2006

End Date: 2006

Funder: Australian Research Council

Multi-Purpose Mass Spectrometry Facility

Start Date: 2009

End Date: 2009

Funder: Australian Research Council

High Performance Chromatography Based On Nanostructured Monolithic Polymers

Start Date: 2009

End Date: 2013

Funder: Australian Research Council

ARC Research Hub For Integrated Device For End-user Analysis At Low-levels

Start Date: 2015

End Date: 2019

Funder: Australian Research Council

Using Innovative Fishing Technology To Research The Biology Of Antarctic Krill

Start Date: 2014

End Date: 2017

Funder: Australian Research Council

Pre-blast Screening Of Improvised Explosive Devices - A National Counter-terrorism Initiative

Start Date: 2006

End Date: 2009

Funder: Australian Research Council

In-line SPE-CE For The Direct Determination Of Drugs And Metabolites In Biological Fluids Based On Porous Polymer Monoliths

Start Date: 2004

End Date: 2007

Funder: Australian Research Council

Polymer Nanoparticles And Their Assembled Supracolloidal Monolithic Structures For Applications In Separation Science

Start Date: 2013

End Date: 2015

Funder: Australian Research Council

Synthesis, Characterisation And Evaluation Of Novel Ion-exchange Polymer Monolithic Stationary Phases For Separation Science

Start Date: 2009

End Date: 2012

Funder: Australian Research Council

Purchase Of A Multi-purpose Schottky Field Emission Gun Scanning Electron Microscope

Start Date: 2010

End Date: 2010

Funder: Australian Research Council

Purchase Of A High Resolution Organic Mass Spectrometer

Start Date: 2007

End Date: 2007

Funder: Australian Research Council

Probing The Tasmanian Devil Serum Proteome For Preclinical Diagnosis Of Devil Facial Tumour Disease

Start Date: 2007

End Date: 2008

Funder: Australian Research Council

Purchase Of A High Resolution Nuclear Magnetic Resonance Spectrometer With Liquid Chromatography Module

Start Date: 2012

End Date: 2012

Funder: Australian Research Council

Bioanalytical Microchips Based On Integrated, Application Tailored Monolithic Modules

Start Date: 2006

End Date: 2008

Funder: Australian Research Council

ARC Training Centre For Portable Analytical Separation Technologies

Start Date: 2014

End Date: 2016

Funder: Australian Research Council

Development Of A Digital Transmission Electron Microscope Facility In Tasmania

Start Date: 2014

End Date: 2014

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE100100107

Start Date: 2010

End Date: 12-2010

Amount: $400,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP130101471

Start Date: 06-2013

End Date: 04-2019

Amount: $330,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0668471

Start Date: 2006

End Date: 12-2006

Amount: $262,706.00

Funder: Australian Research Council

Industrial Transformation Training Centres - Grant ID: IC140100022

Start Date: 10-2014

End Date: 06-2019

Amount: $2,148,935.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE200100183

Start Date: 2020

End Date: 06-2021

Amount: $950,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0666121

Start Date: 03-2006

End Date: 12-2009

Amount: $180,000.00

Funder: Australian Research Council

Industrial Transformation Research Hubs - Grant ID: IH150100028

Start Date: 03-2017

End Date: 12-2023

Amount: $3,708,510.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0669302

Start Date: 09-2006

End Date: 08-2010

Amount: $530,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE210100183

Start Date: 2021

End Date: 09-2022

Amount: $715,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE210100155

Start Date: 2021

End Date: 06-2022

Amount: $909,079.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0987318

Start Date: 02-2009

End Date: 10-2013

Amount: $560,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0775570

Start Date: 2007

End Date: 12-2007

Amount: $570,000.00

Funder: Australian Research Council

ARC Future Fellowships - Grant ID: FT0990521

Start Date: 02-2010

End Date: 04-2015

Amount: $686,400.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE140100174

Start Date: 2014

End Date: 07-2016

Amount: $380,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP140100412

Start Date: 06-2015

End Date: 06-2020

Amount: $491,700.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP180101285

Start Date: 10-2019

End Date: 10-2023

Amount: $441,630.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0776804

Start Date: 2007

End Date: 12-2008

Amount: $59,626.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE120100018

Start Date: 01-2012

End Date: 07-2013

Amount: $630,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0453052

Start Date: 2004

End Date: 12-2009

Amount: $320,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0989491

Start Date: 2009

End Date: 12-2009

Amount: $172,025.00

Funder: Australian Research Council