ORCID Profile
0000-0001-9057-294X
Current Organisation
University of South Australia
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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.
Publisher: American Chemical Society (ACS)
Date: 20-06-2023
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.
Publisher: Elsevier BV
Date: 09-2021
Publisher: Elsevier BV
Date: 06-2023
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.
Publisher: Elsevier BV
Date: 11-2013
Publisher: American Chemical Society (ACS)
Date: 26-01-2021
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.
Publisher: Springer Science and Business Media LLC
Date: 07-1991
DOI: 10.1038/352311A0
Publisher: Wiley
Date: 23-05-2011
Abstract: In the early 1990s, three research groups simultaneously developed continuous macroporous rod‐shaped polymeric systems to eliminate the problem of flow through the interparticle spaces generally presented by the chromatography columns that use particles as filler. The great advantage of those materials, forming a continuous phase rod, is to increase the mass transfer by convective transport, as the mobile phase is forced to go through all means of separation, in contrast to particulate media where the mobile phase flows through the interparticle spaces. Due to their special characteristics, the monolithic polymers are used as base‐supports in different separation techniques, those chromatographic processes being the most important and, to a greater extent, those involving the separation of biomolecules as in the case of affinity chromatography. This mini‐review reports the contributions of several groups to the development of macroporous monoliths and their modification by immobilization of specific ligands on the products for their application in affinity chromatography.
Publisher: Elsevier BV
Date: 11-2012
Publisher: MDPI AG
Date: 18-12-2009
DOI: 10.3390/MA2042429
Publisher: Springer Science and Business Media LLC
Date: 07-1991
DOI: 10.1038/352219A0
Publisher: American Chemical Society (ACS)
Date: 28-07-2010
DOI: 10.1021/JF101651Y
Abstract: The immobilization of caffeic acid (CA) on a polypropylene (PP) film was successfully performed through the covalent binding of the caffeoyl chloride on a modified polymeric surface of PP films grafted with hydroxyethyl methacrylate as monomer (PP-g-HEMA). The different reaction steps were monitored by FT-IR spectroscopy. The synthesized films were characterized by Folin-Ciocalteu method by measuring the available phenolic groups as caffeic acid equivalents linked to the surface. The antioxidant efficiency of the modified polymers was evaluated by typical spectrophometric methods, such as the bleaching of radicals DPPH(•) and ABTS(•+), and the inhibition of the enzymatically induced coupled oxidation of linoleic acid and betacarotene. The available phenolic groups on the modified film presented a good correlation with the antiradical activity toward DPPH(•). Moreover, the polymer synthesized in this work showed a good protective activity against ascorbic acid oxidation in real s les of orange juice.
Publisher: Springer Science and Business Media LLC
Date: 28-06-2005
Publisher: Springer Science and Business Media LLC
Date: 1990
DOI: 10.1038/343240A0
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.
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.
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.
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.
Publisher: CMA Joule Inc.
Date: 09-2015
DOI: 10.1503/JPN.140262
Abstract: Previous studies have reported MRI abnormalities of the corpus callosum (CC) in patients with bipolar disorder (BD), although only a few studies have directly compared callosal areas in psychotic versus nonpsychotic patients with this disorder. We sought to compare regional callosal areas in a large international multicentre s le of patients with BD and healthy controls. We analyzed anatomic T1 MRI data of patients with BD-I and healthy controls recruited from 4 sites (France, Germany, Ireland and the United States). We obtained the mid-sagittal areas of 7 CC subregions using an automatic CC delineation. Differences in regional callosal areas between patients and controls were compared using linear mixed models (adjusting for age, sex, handedness, brain volume, history of alcohol abuse/dependence, lithium or antipsychotic medication status, symptomatic status and site) and multiple comparisons correction. We also compared regional areas of the CC between patients with BD with and without a history of psychotic features. We included 172 patients and 146 controls in our study. Patients with BD had smaller adjusted mid-sagittal CC areas than controls along the posterior body, the isthmus and the splenium of the CC. Patients with a positive history of psychotic features had greater adjusted area of the rostral CC region than those without a history of psychotic features. We found small to medium effect sizes, and there was no calibration technique among the sites. Our results suggest that BD with psychosis is associated with a different pattern of interhemispheric connectivity than BD without psychosis and could be considered a relevant neuroimaging subtype of BD.
Publisher: Elsevier BV
Date: 12-2008
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.
Publisher: Wiley
Date: 30-11-2018
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.
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.
Publisher: Springer Science and Business Media LLC
Date: 08-1993
DOI: 10.1038/364603A0
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.
Publisher: Springer Science and Business Media LLC
Date: 1992
DOI: 10.1038/355213B0
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.
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.
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).
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.
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.
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.
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.
Publisher: Elsevier BV
Date: 05-2018
Publisher: Wiley
Date: 11-10-2006
DOI: 10.1002/POLA.21768
Publisher: American Astronomical Society
Date: 06-1992
DOI: 10.1086/171379
Publisher: Elsevier BV
Date: 03-2021
Publisher: Elsevier BV
Date: 02-2023
Publisher: Elsevier BV
Date: 04-2010
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
No related grants have been discovered for Ruben Dario Arrua.