Xavier Conlan

Elite hairy roots of Ocimum basilicum as a new source of rosmarinic acid and antioxidants

Publisher: Springer Science and Business Media LLC

Date: 17-03-2016

DOI: 10.1007/S11240-016-0973-X

Acidic Potassium Permanganate Chemiluminescence for the Determination of Antioxidant Potential in Three Cultivars of Ocimum basilicum

Publisher: Springer Science and Business Media LLC

Date: 23-01-2016

DOI: 10.1007/S11130-016-0527-8

Abstract: Ocimum basilicum, a member of the family Lamiaceae, is a rich source of polyphenolics that have antioxidant properties. The present study describes the development and application of an online HPLC-coupled acidic potassium permanganate chemiluminescence assay for the qualitative and quantitative assessment of antioxidants in three cultivars of O. basilicum grown under greenhouse conditions. The chemiluminescence based assay was found to be a sensitive and efficient method for assessment of total and in idual compound antioxidant potential. Leaves, flowers and roots were found to be rich reserves of the antioxidant compounds which showed intense chemiluminescence signals. The polyphenolics such as rosmarinic, chicoric, caffeic, p-coumaric, m-coumaric and ferulic acids showed antioxidant activity. Further, rosmarinic acid was found to be the major antioxidant component in water-ethanol extracts. The highest levels of rosmarinic acid was found in the leaves and roots of cultivars "holy green" (14.37 11.52 mM/100 g DW respectively) followed by "red rubin" (10.02 10.75 mM/100 g DW respectively) and "subja" (6.59 4.97 mM/100 g DW respectively). The sensitivity, efficiency and ease of use of the chemiluminescence based assay should now be considered for its use as a primary method for the identification and quantification of antioxidants in plant extracts.

Synthesis and preliminary investigations into norbornane-based amphiphiles and their self-assembly

Publisher: Royal Society of Chemistry (RSC)

Date: 2013

DOI: 10.1039/C3NJ00145H

Rhizophagus irregularis as an elicitor of rosmarinic acid and antioxidant production by transformed roots of Ocimum basilicum in an in vitro co-culture system

Publisher: Springer Science and Business Media LLC

Date: 02-08-2016

DOI: 10.1007/S00572-016-0721-4

Abstract: Arbuscular mycorrhiza is a symbiotic association formed between plant roots and soil borne fungi that alter and at times improve the production of secondary metabolites. Detailed information is available on mycorrhizal development and its influence on plants grown under various edapho-climatic conditions, however, very little is known about their influence on transformed roots that are rich reserves of secondary metabolites. This raises the question of how mycorrhizal colonization progresses in transformed roots grown in vitro and whether the mycorrhizal fungus presence influences the production of secondary metabolites. To fully understand mycorrhizal ontogenesis and its effect on root morphology, root biomass, total phenolics, rosmarinic acid, caffeic acid and antioxidant production under in vitro conditions, a co-culture was developed between three Agrobacterium rhizogenes-derived, elite-transformed root lines of Ocimum basilicum and Rhizophagus irregularis. We found that mycorrhizal ontogenesis in transformed roots was similar to mycorrhizal roots obtained from an in planta system. Mycorrhizal establishment was also found to be transformed root line-specific. Colonization of transformed roots increased the concentration of rosmarinic acid, caffeic acid and antioxidant production while no effect was observed on root morphological traits and biomass. Enhancement of total phenolics and rosmarinic acid in the three mycorrhizal transformed root lines was found to be transformed root line-specific and age dependent. We reveal the potential of R. irregularis as a biotic elicitor in vitro and propose its incorporation into commercial in vitro secondary metabolite production via transformed roots.

Application of a digital stringing protocol on buried fabrics

Publisher: Informa UK Limited

Date: 22-01-2029

DOI: 10.1080/00450618.2019.1569142

Correlation between acidic potassium permanganate chemiluminescence and in vitro cell culture assay: Physiologically meaningful antioxidant activity

Publisher: Royal Society of Chemistry (RSC)

Date: 2010

DOI: 10.1039/B9AY00242A

In vitro and in situ screening systems for morphological and phytochemical analysis of Withania somnifera germplasms

Publisher: Springer Science and Business Media LLC

Date: 13-12-2015

DOI: 10.1007/S11240-014-0673-3

Insight into the swelling mechanism involved in the recovery of serial numbers erased from polymer surfaces

Publisher: Wiley

Date: 2011

DOI: 10.1002/SIA.3510

Abstract: Imaging SIMS is used to investigate the recovery of erased serial numbers from polypropylene, polycarbonate and polyvinylchloride substrates. The recovery of the serial numbers is initiated by a swelling mechanism due to the application of two swelling agents: methyleugenol and cinnamaldehyde. The localization of the characteristic molecular ions for the swelling agents is observed in regions associated with erased characters. This study examines and evaluates SIMS images to discover the optimum combination of the polymer and solvents. The results are discussed in reference to the Hildebrand solubility parameter and comments upon the limitations of this suggested indicator. Copyright © 2010 John Wiley & Sons, Ltd.

Controllable graphene oxide mediated efficient electron transfer pathways across self-assembly monolayers: A new class of graphene based electrodes

Publisher: Elsevier BV

Date: 08-2016

DOI: 10.1016/J.ELECTACTA.2016.05.143

Protocols for finding the most orthogonal dimensions for two-dimensional high performance liquid chromatography

Publisher: Elsevier BV

Date: 03-2015

DOI: 10.1016/J.TALANTA.2014.11.037

Abstract: The selection of two high performance liquid chromatography (HPLC) columns with vastly different retention mechanisms is vital for performing effective two-dimensional (2D-) HPLC. This paper reports on a systematic method to select a pair of HPLC columns that provide the most different separations for a given s le. This was completed with the aid of a HPLC simulator that predicted retention profiles on the basis of real experimental data, which is difficult when the contents of s le matrices are largely-or completely-unknown. Peaks from the same compounds must first be matched between chromatograms to compare the retention profiles and optimised 2D-HPLC column selection. In this work, two methods of matching peaks between chromatograms were explored and an optimal pair of chromatography columns was selected for 2D-HPLC. First, a series of 17 antioxidants were selected as an analogue for a coffee extract. The predicted orthogonality of the standards was 39%, according to the fractional surface coverage 'bins' method, which was close to the actual space utilisation of the standard mixture, 44%. Moreover, the orthogonality for the 2D-HPLC of coffee matched the predicted value of 38%. The second method employed a complex s le matrix of urine to optimise the column selections. Seven peaks were confidently matched between chromatograms by comparing relative peak areas of two detection strategies: UV absorbance and potassium permanganate chemiluminescence. It was found that the optimal combinations had an orthogonality of 35% while the actual value was closer to 30%.

Influence of Heat on Biological Activity and Concentration of Oleocanthala Natural Anti-inflammatory Agent in Virgin Olive Oil

Publisher: American Chemical Society (ACS)

Date: 25-02-2009

DOI: 10.1021/JF803154W

Abstract: The olive oil phenolic oleocanthal is a natural nonsteroidal anti-inflammatory compound that irritates the oral pharynx in a dose-dependent manner. It has been proposed that the biological activity of oleocanthal is partially responsible for the beneficial health effects of the Mediterranean diet. Virgin olive oil containing oleocanthal is often added as an ingredient in a number of cooked dishes, and therefore it is of great importance to understand how best to preserve the putative health-promoting benefits of this compound, as olive oil phenolics are subject to degradation upon heating in general. One extra virgin olive oil containing 53.9 mg/kg oleocanthal was heated at various temperatures (100, 170, and 240 degrees C) for set time periods (0, 1, 5, 20, 60, and 90 min). Oleocanthal concentrations were quantified using HPLC, and its biological activity was determined with a taste bioassay measuring the intensity of throat irritation. Results demonstrated that oleocanthal was heat stable compared with other olive oil phenolics, with a maximum loss of 16% as determined by HPLC analysis. However, there was a significant decrease of up to 31% (p < 0.05) in the biological activity of oleocanthal as determined by the taste bioassay. Although there was minimal degradation of oleocanthal concentration, there was a significant decrease in the biological activity of oleocanthal upon extended heating time, indicating a possible loss of the putative health -benefiting properties of oleocanthal. Alternatively, the difference in the concentration and biological activity of oleocanthal after heat treatment could be a result of an oleocanthal antagonist forming, decreasing or masking the biological activity of oleocanthal.

A rapid antioxidant assay based on acidic potassium permanganate chemiluminescence

Publisher: Elsevier BV

Date: 10-2010

DOI: 10.1016/J.FOODCHEM.2010.02.050

Evaluation of tris(4,7-diphenyl-1,10-phenanthrolinedisulfonate)ruthenium(II) as a chemiluminescence reagent

Publisher: Elsevier BV

Date: 02-2009

DOI: 10.1016/J.ACA.2008.12.030

Abstract: Previous studies have suggested that tris(4,7-diphenyl-1,10-phenanthrolinedisulfonate)ruthenium(II) (Ru(BPS)(3)(4-)) has great potential as a chemiluminescence reagent in acidic aqueous solution. We have evaluated four different s les of this reagent (two commercially available and two synthesised in our laboratory) in comparison with tris(2,2'-bipyridine)ruthenium(II) (Ru(bipy)(3)(2+)) and tris(1,10-phenanthroline)ruthenium(II) (Ru(phen)(3)(2+)), using a range of structurally erse analytes. In general, Ru(BPS)(3)(4-) produced more intense chemiluminescence, but the oxidised Ru(BPS)(3)(3-) species is less stable in aqueous solution than Ru(bipy)(3)(3+) and produced a greater blank signal than Ru(bipy)(3)(3+) or Ru(phen)(3)(3+), which had a detrimental effect on sensitivity. Although the complex is often depicted with the sulfonate groups of the BPS ligand in the para position on the phenyl rings, NMR characterisation revealed that the commercially available BPS material used in this study was predominantly the meta isomer.

The importance of chain length for the polyphosphate enhancement of acidic potassium permanganate chemiluminescence

Publisher: Elsevier BV

Date: 09-2014

DOI: 10.1016/J.ACA.2014.07.012

Abstract: Sodium polyphosphate is commonly used to enhance chemiluminescence reactions with acidic potassium permanganate through a dual enhancement mechanism, but commercially available polyphosphates vary greatly in composition. We have examined the influence of polyphosphate composition and concentration on both the dual enhancement mechanism of chemiluminescence intensity and the stability of the reagent under analytically useful conditions. The average chain length (n) provides a convenient characterisation, but materials with similar values can exhibit markedly different distributions of phosphate oligomers. There is a minimum polyphosphate chain length (∼6) required for a large enhancement of the emission intensity, but no further advantage was obtained using polyphosphate materials with much longer average chain lengths. Providing there is a sufficient average chain length, the optimum concentration of polyphosphate is dependent on the analyte and in some cases, may be lower than the quantities previously used in routine detection. However, the concentration of polyphosphate should not be lowered in permanganate reagents that have been partially reduced to form high concentrations of the key manganese(III) co-reactant, as this intermediate needs to be stabilised to prevent formation of insoluble manganese(IV).

Deficiency of selenoprotein S, an endoplasmic reticulum resident oxidoreductase, impairs the contractile function of fast-twitch hindlimb muscles

Publisher: American Physiological Society

Date: 08-2018

DOI: 10.1152/AJPREGU.00244.2017

Abstract: Selenoprotein S (Seps1) is an endoplasmic reticulum (ER) resident antioxidant implicated in ER stress and inflammation. In human vastus lateralis and mouse hindlimb muscles, Seps1 localization and expression were fiber-type specific. In male Seps1 +/− heterozygous mice, spontaneous physical activity was reduced compared with wild-type littermates ( d = 1.10, P = 0.029). A similar trend was also observed in Seps1 −/− knockout mice ( d = 1.12, P = 0.051). Whole body metabolism, body composition, extensor digitorum longus (EDL), and soleus mass and myofiber diameter were unaffected by genotype. However, in isolated fast EDL muscles from Seps1 −/− knockout mice, the force frequency curve (FFC 1–120 Hz) was shifted downward versus EDL muscles from wild-type littermates ( d = 0.55, P = 0.002), suggestive of reduced strength. During 4 min of intermittent, submaximal (60 Hz) stimulation, the genetic deletion or reduction of Seps1 decreased EDL force production ( d = 0.52, P 0.001). Furthermore, at the start of the intermittent stimulation protocol, when compared with the 60-Hz stimulation of the FFC, EDL muscles from Seps1 −/− knockout or Seps1 +/− heterozygous mice produced 10% less force than those from wild-type littermates ( d = 0.31, P 0.001 and d = 0.39, P = 0.015). This functional impairment was associated with reduced mRNA transcript abundance of thioredoxin-1 ( Trx1), thioredoxin interacting protein ( Txnip), and the ER stress markers Chop and Grp94, whereas, in slow soleus muscles, Seps1 deletion did not compromise contractile function and Trx1 ( d = 1.38, P = 0.012) and Txnip ( d = 1.27, P = 0.025) gene expression was increased. Seps1 is a novel regulator of contractile function and cellular stress responses in fast-twitch muscles.

The identification of synthetic cannabinoids surface coated on herbal substrates using solid-state nuclear magnetic resonance spectroscopy

Publisher: Elsevier BV

Date: 04-2020

DOI: 10.1016/J.ACA.2019.12.051

The concentration of oleocanthal in olive oil waste

Publisher: Informa UK Limited

Date: 03-2011

DOI: 10.1080/14786419.2010.511214

Abstract: The aim of this study was to determine the concentration of oleocanthal in olive pomace waste and compare this to its concentration in extra-virgin olive oil (EVOO). The concentration of oleocanthal in freshly pressed EVOO and its subsequent waste was analysed at early, mid and late season harvests. Oleocanthal concentrations were quantified using high-performance liquid chromatography-mass spectrometry. In oil, oleocanthal concentration was as follows: 123.24 ± 6.48 mg kg(-1) in early harvest, 114.20 ± 17.42 mg kg(-1) in mid harvest and 152.22 ± 10.54 mg kg(-1) in late harvest. Its concentration in waste was determined to be: 128.25 ± 11.33 mg kg(-1) in early harvest, 112.15 ± 1.51 mg kg(-1) in mid harvest and 62.35 ± 8.00 mg kg(-1) in late harvest. Overall, olive pomace waste is a valuable source of oleocanthal.

Electrochemical Evidences of Chiral Molecule Recognition Using L/D -Cysteine Modified Gold Electrodes

Publisher: Elsevier BV

Date: 05-2017

DOI: 10.1016/J.ELECTACTA.2017.03.180

A non-destructive test to assess the axial heterogeneity of in situ modified monoliths for HPLC

Publisher: Royal Society of Chemistry (RSC)

Date: 2015

DOI: 10.1039/C4AY02812K

Abstract: A multi-location peak parking protocol was developed for a non-destructive assessment of the axial heterogeneity of in situ modified monoliths. This was tested on a column with a surface coverage density gradient along the length of the monolithic rod. Qualitative changes in band broadening were observed and were consistent with theoretical studies.

Determination of Citrus aurantium protoalkaloids using HPLC with acidic potassium permanganate chemiluminescence detection

Publisher: Elsevier BV

Date: 15-03-2010

DOI: 10.1016/J.TALANTA.2009.10.052

Abstract: Acidic potassium permanganate chemiluminescence was explored as a sensitive and selective mode of detection for phenolic phenethylamines (adrenergic amines) in consumer products containing Citrus aurantium extracts. Nine commercially available weight-loss products were analysed using rapid reversed-phase chromatography with a monolithic column (separation time of 4 min). The results were in good agreement with package labelling, with some notable exceptions. The products contained a wide concentration range of synephrine and total adrenergic amines, and the difference in consumer intake was even greater when the manufacturers' recommended daily consumption was considered. The quantity of the extract, often specified on the packaging as equivalent grams of dry C. aurantium fruit, was a poor indicator of the concentration of the active ingredients. Methionine, a thioether amino acid contained in some weight-loss products, was identified as a potential interferent for this mode of detection.

An O-Specific Polysaccharide/Tetanus Toxoid Conjugate Vaccine Induces Protection in Guinea Pigs against Virulent Challenge with Coxiella burnetii

Publisher: MDPI AG

Date: 25-08-2022

DOI: 10.3390/VACCINES10091393

Abstract: Q fever is caused by the bacterium Coxiella burnetii and is spread to humans from infected animals especially goats, sheep and cattle, predominantly when giving birth. There is an effective human vaccine (Q-VAX) against Q fever, and although Q fever is a worldwide problem, the vaccine is only used in Australia due to difficulties associated with its use and the risk of adverse reactions. The desire to protect humans, particularly farmers and abattoir workers, from Q fever prompted the development of a new safe and effective human vaccine without all the difficulties associated with the current vaccine. Candidate vaccines were prepared using purified O-specific polysaccharide (OSP) extracted from the lipopolysaccharide of virulent (phase 1) C. burnetii, strain Nine Mile, which was then conjugated to a tetanus toxoid (TT) carrier protein. Two vaccines were prepared using OSP from C. burnetii grown in embryonated eggs (vaccine A) and axenic media (vaccine B). Vaccines with or without alum adjuvant were used to vaccinate guinea pigs, which were later challenged by intranasal inoculation with virulent C. burnetii. Both vaccines protected guinea pigs from fever and loss of weight post challenge. Post-mortem s les of the spleen, liver and kidney of vaccinated guinea pigs contained substantially less C. burnetii DNA as measured by PCR than those of the unvaccinated control animals. This study demonstrated that a C. burnetii OSP-TT conjugate vaccine is capable of inducing protection against virulent C. burnetii in guinea pigs. Additionally, OSP derived from C. burnetii grown in axenic media compared to OSP from embryonated eggs is equivalent in terms of providing a protective immune response.

Determination of morphine in culinary poppy seed tea extractions using high performance liquid chromatography with chemiluminescence detection

Publisher: Informa UK Limited

Date: 23-01-2019

DOI: 10.1080/00450618.2019.1569152

Parallel segmented outlet flow high performance liquid chromatography with multiplexed detection

Publisher: Elsevier BV

Date: 11-2013

DOI: 10.1016/J.ACA.2013.04.014

Abstract: We describe a new approach to multiplex detection for HPLC, exploiting parallel segmented outlet flow - a new column technology that provides pressure-regulated control of eluate flow through multiple outlet channels, which minimises the additional dead volume associated with conventional post-column flow splitting. Using three detectors: one UV-absorbance and two chemiluminescence systems (tris(2,2'-bipyridine)ruthenium(III) and permanganate), we examine the relative responses for six opium poppy (Papaver somniferum) alkaloids under conventional and multiplexed conditions, where approximately 30% of the eluate was distributed to each detector and the remaining solution directed to a collection vessel. The parallel segmented outlet flow mode of operation offers advantages in terms of solvent consumption, waste generation, total analysis time and solute band volume when applying multiple detectors to HPLC, but the manner in which each detection system is influenced by changes in solute concentration and solution flow rates must be carefully considered.

Direct Detection of Biologically Significant Thiols and Disulfides with Manganese(IV) Chemiluminescence

Publisher: American Chemical Society (ACS)

Date: 06-07-2011

DOI: 10.1021/AC2010668

Abstract: The quantification of low-molecular mass thiols and disulfides involved in cellular redox processes is hindered by oxidation or degradation of analytes during conventional s le preparation steps (including deproteinization and derivatization). Researchers therefore seek techniques that minimize s le handling and permit direct detection of thiols and disulfides within a single chromatographic separation. We demonstrate a new HPLC procedure for these biologically important analytes that incorporates direct chemiluminescence detection with a manganese(IV) reagent. A mixture of seven thiols and disulfides (cysteine, N-acetylcysteine, homocysteine, glutathione (GSH), glutathione disulfide (GSSG), cystine, and homocystine) in their native forms were separated using a C18 column within 20 min. Detection limits for these analytes ranged from 5 × 10(-8) to 1 × 10(-7) M, and the precision for retention times and peak areas was excellent, with relative standard deviations of less than 0.3% and 2%, respectively. This approach was employed to determine two key biomarkers of oxidative stress, GSH and GSSG, in whole blood taken from 12 healthy volunteers. S les were deproteinized, centrifuged, and diluted prior to analysis using a simple procedure that was shown to avoid significant artificial oxidation of GSH.

Atomically-thin Schottky-like photo-electrocatalytic cross-flow membrane reactors for ultrafast remediation of persistent organic pollutants

Publisher: Elsevier BV

Date: 06-2022

DOI: 10.1016/J.WATRES.2022.118519

Abstract: The remediation of persistent organic pollutants in surface and ground water represents a major environmental challenge worldwide. Conventional physico-chemical techniques do not efficiently remove such persistent organic pollutants and new remediation techniques are therefore required. Photo-electro catalytic membranes represent an emerging solution that can combine photocatalytic and electrocatalytic degradation of contaminants along with molecular sieving. Herein, macro-porous photo-electro catalytic membranes were prepared using conductive and porous stainless steel metal membranes decorated with nano coatings of semiconductor photocatalytic metal oxides (TiO

Determination of neurotransmitters and their metabolites using one- and two-dimensional liquid chromatography with acidic potassium permanganate chemiluminescence detection

Publisher: Springer Science and Business Media LLC

Date: 07-12-2013

DOI: 10.1007/S00216-013-7514-9

Abstract: High-performance liquid chromatography with chemiluminescence detection based on the reaction with acidic potassium permanganate and formaldehyde was explored for the determination of neurotransmitters and their metabolites. The neurotransmitters norepinephrine and dopamine were quantified in the left and right hemispheres of rat hippoc us, nucleus accumbens and prefrontal cortex, and the metabolites vanillylmandelic acid, 3,4-dihydrophenylacetic acid, 5-hydroxyindole-3-acetic acid and homovanillic acid were identified in human urine. Under optimised chemiluminescence reagent conditions, the limits of detection for these analytes ranged from 2.5 × 10(-8) to 2.5 × 10(-7) M. For the determination of neurotransmitter metabolites in urine, a two-dimensional high-performance liquid chromatography (2D-HPLC) separation operated in heart-cutting mode was developed to overcome the peak capacity limitations of the one-dimensional separation. This approach provided the greater separation power of 2D-HPLC with analysis times comparable to conventional one-dimensional separations.

The presence of background DNA on common entry points to homes

Publisher: Elsevier BV

Date: 12-2019

DOI: 10.1016/J.FSIGSS.2019.10.177

Comparison of homoleptic and heteroleptic 2,2′-bipyridine and 1,10-phenanthroline ruthenium complexes as chemiluminescence and electrochemiluminescence reagents in aqueous solution

Publisher: Elsevier BV

Date: 03-2009

DOI: 10.1016/J.ACA.2008.12.042

Abstract: We have conducted a comprehensive comparative study of Ru(bipy)(3)(2+), Ru(bipy)(2)(phen)(2+), Ru(bipy)(phen)(2)(2+), and Ru(phen)(3)(2+) as chemiluminescence and electrochemiluminescence (ECL) reagents, to address several previous conflicting observations and gain a greater insight into their potential for chemical analysis. Clear trends were observed in many of their spectroscopic and electrochemical properties, but the relative chemiluminescence or ECL intensity with a range of analytes/co-reactants is complicated by the contribution of numerous (sometimes opposing) factors. Significantly, the reversibility of cyclic voltammetric responses for the complexes decreased as the number of phenanthroline ligands was increased, due to the lower stability of their ruthenium(III) form in the aqueous solvent. This trend was also evident over a longer timescale when the ruthenium(III) form was spectrophotometrically monitored after chemical oxidation of the ruthenium(II) complexes. In general, the greater stability of Ru(bipy)(3)(3+) resulted in lower blank signals, although this effect was less pronounced with ECL, where the reagent is oxidised in the presence of the co-reactants. Nevertheless, this shows the need to compare signal-to-blank ratios or detection limits, rather than the more common comparisons of overall signal intensity for different ruthenium complexes. Furthermore, our results support previous observations that, compared to Ru(bipy)(3)(2+), Ru(phen)(3)(2+) provides greater ECL and chemiluminescence intensities with oxalate, which in some circumstances translates to superior detection limits, but they do not support the subsequent generalised notion that Ru(phen)(3)(2+) is a more sensitive reagent than Ru(bipy)(3)(2+) for all analytes.

Presentation methodologies: an assessment for forensic signature analysis

Publisher: Informa UK Limited

Date: 25-03-2020

DOI: 10.1080/00450618.2019.1592227

Salicylic acid suppression of clubroot in broccoli (Brassicae oleracea var. italica) caused by the obligate biotroph Plasmodiophora brassicae

Publisher: Springer Science and Business Media LLC

Date: 18-10-2012

DOI: 10.1007/S13313-012-0167-X

High performance liquid chromatography with two simultaneous on-line antioxidant assays: Evaluation and comparison of espresso coffees

Publisher: Elsevier BV

Date: 15-05-2010

DOI: 10.1016/J.TALANTA.2010.01.024

Abstract: The antioxidant profiles of various espresso coffees were established using HPLC with UV-absorbance detection and two rapid, simultaneous, on-line chemical assays that enabled the relative reactivity of s le components to be screened. The assays were based on (i) the colour change associated with reduction of the 2,2'-diphenyl-1-picrylhydrazyl radical (DPPH*) and (ii) the emission of light (chemiluminescence) upon reaction with acidic potassium permanganate. Results from the two approaches were similar and reflected the complex array of antioxidant species present in the s les. However, some differences in selectivity were observed. Chromatograms generated with the chemiluminescence assay contained more peaks, which was ascribed to the greater sensitivity of the reagent towards minor, readily oxidisable s le components. The three coffee s les produced closely related profiles, signifying their fundamentally similar chemical compositions and origin. Nevertheless, the overall intensity and complexity of the s les in both UV absorption and antioxidant assay chromatograms were aligned with the manufacturers description of flavour intensity and character.

Chemiluminescence and electrochemiluminescence detection of controlled drugs

Publisher: Wiley

Date: 10-12-2010

DOI: 10.1002/DTA.236

Abstract: We review the determination of various controlled drugs (opioids, tranquilizers, stimulants, and hallucinogens) using flow-analysis methodologies (flow injection analysis, high performance liquid chromatography, capillary electrophoresis, and microfluidic devices) with chemiluminescence and electrochemiluminescence reagents such as luminol, diaryloxalates, tris(2,2'-bipyridine)ruthenium(II), permanganate, manganese(IV), and sulfite, for industrial, clinical, pharmaceutical, and forensic science applications.

The use of microfluidic devices in studies of differential sperm chemotaxis

Publisher: Elsevier BV

Date: 10-2022

DOI: 10.1016/J.TIBTECH.2022.06.014

Abstract: Differential sperm chemotaxis describes differences among male-female pairings in chemotactic responses of sperm to egg (or female)-derived chemical attractants. Microfluidic devices provide powerful platforms in which to study this complex gamete interaction. Here, we describe key challenges and potential solutions in applying this state-of-the-art technique to differential sperm chemotaxis.

Evaluation of the asymmetric least squares baseline algorithm through the accuracy of statistical peak moments

Publisher: Elsevier BV

Date: 04-2013

DOI: 10.1016/J.CHROMA.2013.02.012

Abstract: This manuscript evaluates the performance of the Eilers' smoothing algorithm by comparing the third central statistical peak moment of simulated peaks to their true value. Peaks were simulated by imposing an exponentially modified Gaussian peak profile onto a random segment of pre-recorded high performance liquid chromatography baseline. Prior to moment calculation the noise was removed from the simulated curves and the signal was subtracted by the approximated baseline. We found that with a signal to noise ratio of 1000 an 11% relative error was observed between the practical and true third statistical moment. The Eilers' smoothing algorithm was observed to both reduced noise and baseline correct without distorting the shape of the chromatographic peak.

Background DNA on flooring: The effect of cleaning

Publisher: Elsevier BV

Date: 12-2019

DOI: 10.1016/J.FSIGSS.2019.10.178

The cyclic nature of soil chemistry: Forensic analysis with the aid of ultra-high performance liquid chromatography

Publisher: Elsevier BV

Date: 12-2022

DOI: 10.1016/J.TALO.2022.100126

Overcoming solvent mismatch limitations in 2D-HPLC with temperature programming of isocratic mobile phases

Publisher: Royal Society of Chemistry (RSC)

Date: 2016

DOI: 10.1039/C5AY02528A

Abstract: Solvent incompatibility is a limiting factor when implementing 2D-HPLC. A programmed temperature gradient in the first dimension was developed to overcome this limitation by allowing an isocratic separation while maintaining selectivity.

Investigation into the prevalence of background DNA on flooring within houses and its transfer to a contacting surface

Publisher: Elsevier BV

Date: 2020

DOI: 10.1016/J.FORSCIINT.2020.110563

The assessment of π–π selective stationary phases for two-dimensional HPLC analysis of foods: Application to the analysis of coffee

Publisher: Elsevier BV

Date: 15-09-2010

DOI: 10.1016/J.TALANTA.2010.06.065

Abstract: Differences between alkyl, dipole-dipole, hydrogen bonding, and pi-pi selective surfaces represented by non-resonance and resonance pi-stationary phases have been assessed for the separation of 'Ristretto' café espresso by employing 2DHPLC techniques with C18 phase selectivity detection. Geometric approach to factor analysis (GAFA) was used to measure the detected peaks (N), spreading angle (beta), correlation, practical peak capacity (n(p)) and percentage usage of the separations space, as an assessment of selectivity differences between regional quadrants of the two-dimensional separation plane. Although all tested systems were correlated to some degree to the C18 dimension, regional measurement of separation ergence revealed that performance of specific systems was better for certain s le components. The results illustrate that because of the complexity of the 'real' s le obtaining a truly orthogonal two-dimensional system for complex s les of natural origin may be practically impossible.

Blind column selection protocol for two-dimensional high performance liquid chromatography

Publisher: Elsevier BV

Date: 07-2016

DOI: 10.1016/J.TALANTA.2016.03.056

Abstract: The selection of two orthogonal columns for two-dimensional high performance liquid chromatography (LC×LC) separation of natural product extracts can be a labour intensive and time consuming process and in many cases is an entirely trial-and-error approach. This paper introduces a blind optimisation method for column selection of a black box of constituent components. A data processing pipeline, created in the open source application OpenMS®, was developed to map the components within the mixture of equal mass across a library of HPLC columns LC×LC separation space utilisation was compared by measuring the fractional surface coverage, fcoverage. It was found that for a test mixture from an opium poppy (Papaver somniferum) extract, the combination of diphenyl and C18 stationary phases provided a predicted fcoverage of 0.48 and was matched with an actual usage of 0.43. OpenMS®, in conjunction with algorithms designed in house, have allowed for a significantly quicker selection of two orthogonal columns, which have been optimised for a LC×LC separation of crude extractions of plant material.

Determination of intracellular glutathione and cysteine using HPLC with a monolithic column after derivatization with monobromobimane

Publisher: Wiley

Date: 2010

DOI: 10.1002/BMC.1327

Abstract: An optimized high-performance liquid chromatography (HPLC) method is used to show that, as myoblasts differentiate into multinucleated muscle fibers, there is a shift to a more oxidized cell redox state. The HPLC method incorporated derivatization with monobromobimane for the determination of the reduced (GSH) and oxidized (GSSG) forms of glutathione and the reduced (Cys) and oxidized (CysSS) forms of cysteine. The derivatization was optimized to improve the sensitivity of the approach the limits of detection for glutathione and cysteine were 3 x 10(-8) and 5 x 10(-8) M, respectively.

Extraction, identification and detection of synthetic cannabinoids found pre-ban in herbal products in Victoria, Australia

Publisher: Elsevier BV

Date: 03-2018

DOI: 10.1016/J.FORC.2017.12.003

Differential regulation of cellular stress responses by the endoplasmic reticulum-resident Selenoprotein S (Seps1) in proliferating myoblasts versus myotubes

Publisher: Wiley

Date: 12-2018

DOI: 10.14814/PHY2.13926

'Cathodic' electrochemiluminescence of [Ru(bpy)3]²⁺ and tri-: N -propylamine confirmed as emission at the counter electrode

Publisher: Royal Society of Chemistry (RSC)

Date: 2019

DOI: 10.1039/C9CC03201K

Abstract: Monitoring emission and potentials at both the working and counter electrodes provides new insight into a proposed cathodic electrochemiluminescence system.

The analysis of café espresso using two-dimensional reversed phase–reversed phase high performance liquid chromatography with UV-absorbance and chemiluminescence detection

Publisher: Elsevier BV

Date: 15-09-2010

DOI: 10.1016/J.TALANTA.2010.06.066

Abstract: In this study, an activity based screening technique combining two-dimensional liquid chromatography (2DHPLC) with UV-absorbance and chemiluminescence detection was applied to study "Ristretto", "Decaffeinatto" and "Volluto" espresso coffees. This technique, which coupled the separation power of 2DHPLC with the sensitivity and selectivity of the chemiluminescence detection, offers great potential for screening complex s les for antioxidant compounds. Detailed information regarding the complexity of the s le, and the variation between these three coffees could be obtained using this multidimensional-hyphenated method of analysis.

Off-line two-dimensional liquid chromatography for metabolomics: an example using Agaricus bisporus mushrooms exposed to UV irradiation

Publisher: Springer Science and Business Media LLC

Date: 13-11-2015

DOI: 10.1007/S11306-014-0749-4

Why do street signs taste so good? A community ballistics project

Publisher: Informa UK Limited

Date: 22-01-2019

DOI: 10.1080/00450618.2019.1568551

Forensic undergraduate cohort; job readiness curricula

Publisher: Informa UK Limited

Date: 22-01-2019

DOI: 10.1080/00450618.2019.1568550

Self-Assembled Core–Satellite Gold Nanoparticle Networks for Ultrasensitive Detection of Chiral Molecules by Recognition Tunneling Current

Publisher: American Chemical Society (ACS)

Date: 29-04-2016

DOI: 10.1021/ACSNANO.6B00216

Abstract: Chirality sensing is a very challenging task. Here, we report a method for ultrasensitive detection of chiral molecule l/d-carnitine based on changes in the recognition tunneling current across self-assembled core-satellite gold nanoparticle (GNP) networks. The recognition tunneling technique has been demonstrated to work at the single molecule level where the binding between the reader molecules and the analytes in a nanojunction. This process was observed to generate a unique and sensitive change in tunneling current, which can be used to identify the analytes of interest. The molecular recognition mechanism between amino acid l-cysteine and l/d-carnitine has been studied with the aid of SERS. The different binding strength between homo- or heterochiral pairs can be effectively probed by the copper ion replacement fracture. The device resistance was measured before and after the sequential exposures to l/d-carnitine and copper ions. The normalized resistance change was found to be extremely sensitive to the chirality of carnitine molecule. The results suggested that a GNP networks device optimized for recognition tunneling was successfully built and that such a device can be used for ultrasensitive detection of chiral molecules.

Storage of extra virgin olive oil and its effect on the biological activity and concentration of oleocanthal

Publisher: Elsevier BV

Date: 03-2013

DOI: 10.1016/J.FOODRES.2011.03.046

The use of parallel segmented outlet flow columns for enhanced mass spectral sensitivity at high chromatographic flow rates

Publisher: Wiley

Date: 02-03-2012

DOI: 10.1002/RCM.6176

Abstract: Speed of analysis is a significant limitation to current high-performance liquid chromatography/mass spectrometry (HPLC/MS) and ultra-high-pressure liquid chromatography (UHPLC)/MS systems. The flow rate limitations of MS detection require a compromise in the chromatographic flow rate, which in turn reduces throughput, and when using modern columns, a reduction in separation efficiency. Commonly, this restriction is combated through the post-column splitting of flow prior to entry into the mass spectrometer. However, this results in a loss of sensitivity and a loss in efficiency due to the post-extra column dead volume. A new chromatographic column format known as 'parallel segmented flow' involves the splitting of eluent flow within the column outlet end fitting, and in this study we present its application on a HPLC electrospray ionization time-of-flight mass spectrometer. Using parallel segmented flow, column flow rates as high as 2.5 mL/min were employed in the analysis of amino acids without post-column splitting to the mass spectrometer. Furthermore, when parallel segmented flow chromatography columns were employed, the sensitivity was more than twice that of conventional systems with post-column splitting when the same volume of mobile phase was passed through the detector. These finding suggest that this type of column technology will particularly enhance the capabilities of modern LC/MS enabling both high-throughput and sensitive mass spectral detection.

Extraction and Determination of Morphine Present on the Surface of Australian Food Grade Poppy Seeds Using Acidic Potassium Permanganate Chemiluminescence Detection

Publisher: Springer Science and Business Media LLC

Date: 06-03-2020

DOI: 10.1007/S12161-020-01729-Z

Screening of cannabinoids in industrial-grade hemp using two-dimensional liquid chromatography coupled with acidic potassium permanganate chemiluminescence detection

Publisher: Wiley

Date: 07-05-2022

DOI: 10.1002/JSSC.201500088

Abstract: Widely known for its recreational use, the cannabis plant also has the potential to act as an antibacterial agent in the medicinal field. The analysis of cannabis plants roducts in both pharmacological and forensic studies often requires the separation of compounds of interest and/or accurate identification of the whole cannabinoid profile. In order to provide a complete separation and detection of cannabinoids, a new two-dimensional liquid chromatography method has been developed using acidic potassium permanganate chemiluminescence detection, which has been shown to be selective for cannabinoids. This was carried out using a Luna 100 Å CN column and a Poroshell 120 EC-C18 column in the first and second dimensions, respectively. The method has utilized a large amount of the available separation space with a spreading angle of 48.4° and a correlation of 0.66 allowing the determination of more than 120 constituents and mass spectral identification of ten cannabinoids in a single analytical run. The method has the potential to improve research involved in the characterization of sensitive, complex matrices.

Growth kinetics and withanolide production in novel transformed roots of Withania somnifera and measurement of their antioxidant potential using chemiluminescence

Publisher: Springer Science and Business Media LLC

Date: 16-11-2018

DOI: 10.1007/S11240-017-1344-Y

Improved 2D-HPLC of red wine by incorporating pre-process signal-smoothing algorithms

Publisher: Wiley

Date: 18-09-2013

DOI: 10.1002/JSSC.201300616

Abstract: Two multidimensional HPLC separations of an Australian red wine are presented, >70% of the available separation space was used. A porous graphitic carbon (PGC) stationary phase was used as the first dimension in both separations with both RP core-shell and hydrophilic interaction chromatography fully porous columns used separately in the second dimension. To overcome peak analysis problems caused by signal noise and low detection limits, the data were pre-processed with penalised least-squares smoothing. The PGC × RP combination separated 85 peaks with a spreading angle of 71° and the PGC × hydrophilic interaction chromatography separated 207 peaks with a spreading angle of 80°. Both 2D-HPLC steps were completed in 76 min using a comprehensive stop-and-go approach. A smoothing step was added to peak-picking processes and was able to greatly reduce the number of false peaks present due to noise in the chromatograms. The required thresholds were not able to ignore the noise because of the small magnitude of the peaks 1874 peaks were located in the non-smoothed PGC × RP separation that reduced to 227 peaks after smoothing was included.

High-performance liquid chromatography with post-column 2,2′-diphenyl-1-picrylhydrazyl radical scavenging assay: Methodological considerations and application to complex samples

Publisher: Elsevier BV

Date: 08-2010

DOI: 10.1016/J.ACA.2010.06.041

Abstract: An improved post-column 2,2'-diphenyl-1-picrylhydrazyl (DPPH*) radical scavenging assay for the screening of antioxidants in complex matrices was developed. Experimental parameters believed to be influential to DPPH* response were studied in a univariate approach. Optimum conditions were found to be: 5 x 10(-5) M DPPH* reagent prepared in a 75% methanol: 25% 40 mM citric acid-sodium citrate buffer (pH 6) solution, degassed with nitrogen reaction coil of 2 m x 0.25 mm i.d. PEEK tubing detection at 521 nm analysis at room temperature. The analytical utility of this protocol was evaluated by screening for antioxidants in thyme and green tea, in comparison with two commonly employed methodologies.

Influence of base on nitro-aldol (Henry) reaction products for alternative clandestine pathways

Publisher: Informa UK Limited

Date: 22-01-2016

DOI: 10.1080/00450618.2015.1112429

Screening for antioxidants in complex matrices using high performance liquid chromatography with acidic potassium permanganate chemiluminescence detection

Publisher: Elsevier BV

Date: 2011

DOI: 10.1016/J.ACA.2010.10.046

Abstract: The use of high performance liquid chromatography with acidic potassium permanganate chemiluminescence detection to screen for antioxidants in complex plant-derived s les was evaluated in comparison with two conventional post-column radical scavenging assays (2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS(+))). In this approach, acidic potassium permanganate can react with readily oxidisable compounds (potential antioxidants), post-column, to produce chemiluminescence. Using flow injection analysis, experimental parameters that afforded the most suitable permanganate chemiluminescence signal for a range of known antioxidants were studied in a univariate approach. Optimum conditions were found to be: 1×10(-3)M potassium permanganate solution containing 1% (w/v) sodium polyphosphates adjusted to pH 2 with sulphuric acid, delivered at a flow rate of 2.5 mL min(-1) per line. Further investigations showed some differences in detection selectivity between HPLC with the optimised post-column permanganate chemiluminescence detection and DPPH and ABTS(+) assays towards antioxidant standards. However, permanganate chemiluminescence detection was more sensitive. Moreover, screening for antioxidants in green tea, cranberry juice and thyme using potassium permanganate chemiluminescence offers several advantages over the traditional DPPH and ABTS(+) assays, such as faster reagent preparation and superior stability simpler post-column reaction manifold and greater compatibility with fast chromatographic separations using monolithic columns.

Profiling of secondary metabolites in blue lupin inoculated with Phytophthora cinnamomi following phosphite treatment

Publisher: CSIRO Publishing

Date: 2013

DOI: 10.1071/FP13023

Abstract: In order to discover phytochemicals that are potentially bioactive against Phytophthora cinnamomi, (a soil-borne plant pathogen) a metabolite profiling protocol for investigation of metabolic changes in Lupinus angustifolius L. plant roots in response to pathogen challenge has been established. Analysis of the metabolic profiles from healthy and P. cinnamomi-inoculated root tissue with high resolution mass spectrometry and nuclear magnetic resonance spectroscopy confirmed that although susceptible, L. angustifolius upregulated a defence associated genistein and 2′-hydroxygenistein-based isoflavonoid and a soyasapogenol saponin at 12 h post inoculation which increased in concentration at 72 h post inoculation. In contrast to the typical susceptible interaction, the application of a phosphorous-based treatment to L. angustifolius foliage 48 h before P. cinnamomi challenge negated the ability of the pathogen to colonise the root tissue and cause disease. Importantly, although the root profiles of water-treated and phosphite-treated plants post pathogen inoculation contained the same secondary metabolites, concentration variations were observed. Accumulation of secondary metabolites within the P. cinnamomi-inoculated plants confirms that pathogen ingress of the root interstitially occurs in phosphite-treated plants, confirming a direct mode of action against the pathogen upon breaching the root cells.

Determination of urea using high-performance liquid chromatography with fluorescence detection after automated derivatisation with xanthydrol

Publisher: Elsevier BV

Date: 08-2007

DOI: 10.1016/J.CHROMA.2007.05.085

Abstract: A high-performance liquid chromatography (HPLC) method for the determination of urea that incorporates automated derivatisation with xanthydrol (9H-xanthen-9-ol) is described. Unlike the classic xanthydrol approach for the determination of urea, which involves the precipitation of dixanthylurea (N,N'-di-9H-xanthen-9-ylurea), the derivatisation procedure employed in this method produces N-9H-xanthen-9-ylurea, which remains in solution and can be quantified using fluorescence detection (lambda(ex)=213 nm lambda(em)=308 nm) after chromatographic separation from interferences. The limit of detection for urea was 5 x 10(-8) M (0.003 mg L(-1)). This method was applied to the determination of urea in human and animal urine and in wine.

DryLab® optimised two-dimensional high performance liquid chromatography for differentiation of ephedrine and pseudoephedrine based methamphetamine samples

Publisher: Elsevier BV

Date: 11-2014

DOI: 10.1016/J.FORSCIINT.2014.09.018

Abstract: In-silico optimised two-dimensional high performance liquid chromatographic (2D-HPLC) separations of a model meth hetamine seizure s le are described, where an excellent match between simulated and real separations was observed. Targeted separation of model compounds was completed with significantly reduced method development time. This separation was completed in the heart-cutting mode of 2D-HPLC where C18 columns were used in both dimensions taking advantage of the selectivity difference of methanol and acetonitrile as the mobile phases. This method development protocol is most significant when optimising the separation of chemically similar chemical compounds as it eliminates potentially hours of trial and error injections to identify the optimised experimental conditions. After only four screening injections the gradient profile for both 2D-HPLC dimensions could be optimised via simulations, ensuring the baseline resolution of diastereomers (ephedrine and pseudoephedrine) in 9.7 min. Depending on which diastereomer is present the potential synthetic pathway can be categorized.

A preliminary evaluation of the utility of insects and algae for PMI estimation in confined, still-water environments

Publisher: Informa UK Limited

Date: 31-08-2021

DOI: 10.1080/00450618.2021.1973100

Comprehensive sample analysis using high performance liquid chromatography with multi-detection

Publisher: Elsevier BV

Date: 11-2013

DOI: 10.1016/J.ACA.2013.08.013

Abstract: Herein we assess the separation space offered by a liquid chromatography system with an optimised uni-dimensional separation for the determination of the key chemical entities in the highly complex matrix of a tobacco leaf extract. Multiple modes of detection, including UV-visible absorbance, chemiluminescence (acidic potassium permanganate, manganese(IV), and tris(2,2'-bipyridine)ruthenium(III)), mass spectrometry and DPPH radical scavenging were used in an attempt to systematically reduce the data complexity of the s le whilst obtaining a greater degree of molecule-specific information. A large amount of chemical data was obtained, but several limitations in the ability to assign detector responses to particular compounds, even with the aid of complementary detection systems, were observed. Thirty-three compounds were detected via MS on the tobacco extract and 12 out of 32 compounds gave a peak height ratio (PHR) greater than 0.33 on one or more detectors. This paper serves as a case study of these limitations, illustrating why multidimensional chromatography is an important consideration when developing a comprehensive chemical detection system.

Investigating retention characteristics of a mixed-mode stationary phase and the enhancement of monolith selectivity for high-performance liquid chromatography

Publisher: Wiley

Date: 17-06-2014

DOI: 10.1002/JSSC.201400201

Abstract: The synthesis and chromatographic behavior of an analytical size mixed-mode bonded silica monolith was investigated. The monolith was functionalized by an in situ modification process of a bare silica rod with chloro(3-cyanopropyl)dimethyl silane and chlorodimethyl propyl phenyl silane solutions. These ligands were selected in order to combine both resonance and nonresonance π-type bonding within a single separation environment. Selectivity studies were undertaken using n-alkyl benzenes and polycyclic aromatic hydrocarbons in aqueous methanol and acetonitrile mobile phases to assess the methylene and aromatic selectivities of the column. The results fit with the linear solvent strength theory suggesting excellent selectivity of the column was achieved. Comparison studies were performed on monolithic columns that were functionalized separately with cyano and phenyl ligands, suggesting highly conjugated molecules were able to successfully exploit both of the π-type selectivities afforded by the two different ligands on the mixed-mode column.

Improving peak shapes with counter gradients in two-dimensional high performance liquid chromatography

Publisher: Elsevier BV

Date: 04-2014

DOI: 10.1016/J.CHROMA.2014.02.051

Abstract: To achieve the greatest peak capacity in two-dimensional high performance liquid chromatography (2D-HPLC) a gradient should be operated in both separation dimensions. However, it is known that when an injection solvent that is stronger than the initial mobile phase composition is deleterious to peak performance, thus causing problems when cutting a portion from one gradient into another. This was overcome when coupling hydrophilic interaction with reversed phase chromatography by introducing a counter gradient that changed the solvent strength of the second dimension injection. It was found that an injection solvent composition of 20% acetonitrile in water gave acceptable results in one-dimensional simulations with an initial composition of 5% acetonitrile. When this was transferred to a 2D-HPLC separation of standards it was found that a marked improvement in peak shape was gained for the moderately retained analytes (phenol and dimethyl phthalate), some improvement for the weakly retained caffeine and very little change for the strongly retained n-propylbenzene and anthracene which already displayed good chromatographic profiles. This effect was transferred when applied to a 2D-HPLC separation of a coffee extract where the indecipherable retention profile was transformed to a successful application multidimensional chromatography with peaks occupying 71% of the separation space according to the geometric approach to factor analysis.

Chemistry and Health of Olive Oil Phenolics

Publisher: Informa UK Limited

Date: 17-12-2008

DOI: 10.1080/10408390701856223

Abstract: The Mediterranean diet is associated with a lower incidence of atherosclerosis, cardiovascular disease, and certain types of cancer. The apparent health benefits have been partially attributed to the dietary consumption of virgin olive oil by Mediterranean populations. Most recent interest has focused on the biologically active phenolic compounds naturally present in virgin olive oils. Studies (human, animal, in vivo and in vitro) have shown that olive oil phenolics have positive effects on certain physiological parameters, such as plasma lipoproteins, oxidative damage, inflammatory markers, platelet and cellular function, and antimicrobial activity. Presumably, regular dietary consumption of virgin olive oil containing phenolic compounds manifests in health benefits associated with a Mediterranean diet. This paper summarizes current knowledge on the physiological effects of olive oil phenolics. Moreover, a number of factors have the ability to affect phenolic concentrations in virgin olive oil, so it is of great importance to understand these factors in order to preserve the essential health promoting benefits of olive oil phenolic compounds.

A simple device for rapid quantification of cell number from equine buccal swab samples

Publisher: Royal Society of Chemistry (RSC)

Date: 2018

DOI: 10.1039/C8AY00338F

Abstract: This device measures absorbance for the quantification of cell number from buccal swabs by exploiting dye transitions of Bradford's reagent.

A Novelin VitroWhole Plant System for Analysis of Polyphenolics and Their Antioxidant Potential in Cultivars ofOcimum basilicum

Publisher: American Chemical Society (ACS)

Date: 02-10-2014

DOI: 10.1021/JF502709E

Abstract: Plants are an important source for medicinal compounds. Chemical screening and selection is critical for identification of compounds of interest. Ocimum basilicum (Basil) is a rich source of polyphenolics and exhibits high ersity, therefore bioprospecting of a suitable cultivar is a necessity. This study reports on the development of a true to type novel "in vitro system" and its comparison with a conventional system for screening and selection of cultivars for high total phenolics, in idual polyphenolics, and antioxidant content. We have shown for the first time using online acidic potassium permanganate chemiluminescence that extracts from Ocimum basilicum showed antioxidant potential. The current study identified the cultivar specific composition of polyphenolics and their antioxidant properties. Further, a distinct relationship between plant morphotype and polyphenolic content was also found. Of the 15 cultivars examined, "Holy Green", "Red Rubin", and "Basil Genovese" were identified as high polyphenolic producing cultivars while "Subja" was determined to be a low producer. The "in vitro system" enabled differentiation of the cultivars in their morphology, polyphenolic content, and antioxidant activity and is a cheap and efficient method for bioprospecting studies.

Determination of intracellular glutathione and glutathione disulfide using high performance liquid chromatography with acidic potassium permanganate chemiluminescence detection

Publisher: Royal Society of Chemistry (RSC)

Date: 2011

DOI: 10.1039/C1AN00004G

Abstract: Measurement of glutathione (GSH) and glutathione disulfide (GSSG) is a crucial tool to assess cellular redox state. Herein we report a direct approach to determine intracellular GSH based on a rapid chromatographic separation coupled with acidic potassium permanganate chemiluminescence detection, which was extended to GSSG by incorporating thiol blocking and disulfide bond reduction. Importantly, this simple procedure avoids derivatisation of GSH (thus minimising auto-oxidation) and overcomes problems encountered when deriving the concentration of GSSG from 'total GSH'. The linear range and limit of detection for both analytes were 7.5 × 10(-7) to 1 × 10(-5) M, and 5 × 10(-7) M, respectively. GSH and GSSG were determined in cultured muscle cells treated for 24 h with glucose oxidase (0, 15, 30, 100, 250 and 500 mU mL(-1)), which exposed them to a continuous source of reactive oxygen species (ROS). Both analyte concentrations were greater in myotubes treated with 100 or 250 mU mL(-1) glucose oxidase (compared to untreated controls), but were significantly lower in myotubes treated with 500 mU mL(-1) (p < 0.05), which was rationalised by considering measurements of H(2)O(2) and cell viability. However, the GSH/GSSG ratio in myotubes treated with 100, 250 and 500 mU mL(-1) glucose oxidase exhibited a dose-dependent decrease that reflected the increase in intracellular ROS.

Assessing the detectability of antioxidants in two-dimensional high-performance liquid chromatography.

Publisher: Wiley

Date: 17-04-2015

DOI: 10.1002/JSSC.201500054

Abstract: This paper explores the analytical figures of merit of two-dimensional high-performance liquid chromatography for the separation of antioxidant standards. The cumulative two-dimensional high-performance liquid chromatography peak area was calculated for 11 antioxidants by two different methods--the areas reported by the control software and by fitting the data with a Gaussian model these methods were evaluated for precision and sensitivity. Both methods demonstrated excellent precision in regards to retention time in the second dimension (%RSD below 1.16%) and cumulative second dimension peak area (%RSD below 3.73% from the instrument software and 5.87% for the Gaussian method). Combining areas reported by the high-performance liquid chromatographic control software displayed superior limits of detection, in the order of 1 × 10(-6) M, almost an order of magnitude lower than the Gaussian method for some analytes. The introduction of the countergradient eliminated the strong solvent mismatch between dimensions, leading to a much improved peak shape and better detection limits for quantification.

Elemental and molecular profiling of licit, illicit, and niche tobacco

Publisher: Elsevier BV

Date: 09-2016

DOI: 10.1016/J.FORSCIINT.2016.07.023

Abstract: The recognition of differences between regulated large-scale mass manufactured products and the uncontrolled cultivation of tobaccos for illicit purposes plays a significant role within identification of provenance. This research highlights X-ray fluorescence and Fourier transform infrared spectroscopy as useful analytical techniques for the rapid identification of tobacco s les of unknown provenance. Identification of key discriminative features within each technique allowed for the development of typical characteristic profiles for each type of tobacco. Analysis using X-ray fluorescence highlights chlorine, potassium, calcium and iron as key elemental indicators of tobacco provenance. Significant levels of chlorine seen within Snüs s les prompted attempts to visualise chlorine containing regions and structures within the s le. Scanning electron microscopy images showed crystalline structures visible within the Snüs tobacco, structures which Energy dispersive X-ray spectroscopy qualitatively confirmed to contain chlorine. Chloride levels within Snüs s les were quantified using ion chromatography with levels found to range between 0.87mgmL(-1) and 1.28mg. Additionally, FTIR indicated that absorbances attributed to carbonyl stretching at 1050-1150cm(-1), alkane bending at 1350-1480cm(-1) and amide I stretching at 1600-1700cm(-1) highlighting a spectral fingerprint region that allowed for the clear differentiation between different types of tobaccos using PCA analysis, but was limited by differentiation between provenance of cigarettes and hand rolled tobacco. X-ray fluorescence and Fourier transform infrared spectroscopy yielded different information with regards tobacco discrimination and provenance, however both methods overall analysis time and cost reduced indicating usefulness as potential handheld analytical techniques in the field.

The determination and characterisation of 2-naphthyloxycarbonyl chloride derivatised biogenic amines in pet foods

Publisher: Wiley

Date: 05-2012

DOI: 10.1002/JSSC.201200012

Abstract: The need to monitor biogenic amines levels is essential for many areas of the food industry for two main reasons: the caustic nature and potential toxicity of these amines, and the potential to use amine levels as markers for freshness and quality in foodstuffs. Optimised analysis conditions used for the determination of biogenic amines derivatised with 2-napthyloxycarbonyl chloride has been applied to different pet food s les to assess the effectiveness of this method for complex s le matrices. Further to this, the use of high-resolution mass spectrometry has enabled the previously unconfirmed derivatised form of seven biogenic amines to be established. The derivatised forms identified include as mono substituted (tryptamine and histamine), bisubstituted (putrescine, cadaverine and tyramine), trisubstituted (spermidine) and tetrasubstituted (spermine). The methodology of biogenic amine determination was performed successfully to a range of pet food products highlighting the applicability to a variety of complex s le matrices.

Discovery Projects - Grant ID: DP170103290

Start Date: 07-2017

End Date: 12-2020

Amount: $453,500.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP210200707

Start Date: 11-2023

End Date: 11-2026

Amount: $782,714.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP170100909

Start Date: 03-2019

End Date: 12-2024

Amount: $339,300.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP130100681

Start Date: 06-2014

End Date: 12-2016

Amount: $182,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP140100439

Start Date: 06-2014

End Date: 06-2017

Amount: $320,000.00

Funder: Australian Research Council