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Celbridge, Ireland

Plotan M.,Queens University of Belfast | Elliott C.T.,Queens University of Belfast | Scippo M.L.,University of Liege | Muller M.,University of Liege | And 5 more authors.
Analytica Chimica Acta | Year: 2011

The increasing availability and use of sports supplements is of concern as highlighted by a number of studies reporting endocrine disruptor contamination in such products. The health food supplement market, including sport supplements, is growing across the Developed World. Therefore, the need to ensure the quality and safety of sport supplements for the consumer is essential. The development and validation of two reporter gene assays coupled with solid phase sample preparation enabling the detection of estrogenic and androgenic constituents in sport supplements is reported. Both assays were shown to be of high sensitivity with the estrogen and androgen reporter gene assays having an EC50 of 0.01ngmL-1 and 0.16ngmL-1 respectively. The developed assays were applied in a survey of 63 sport supplements samples obtained across the Island of Ireland with an additional seven reference samples previously investigated using LC-MS/MS. Androgen and estrogen bio-activity was found in 71% of the investigated samples. Bio-activity profiling was further broken down into agonists, partial agonists and antagonists. Supplements (13) with the strongest estrogenic bio-activity were chosen for further investigation. LC-MS/MS analysis of these samples determined the presence of phytoestrogens in seven of them. Supplements (38) with androgen bio-activity were also selected for further investigation. Androgen agonist bio-activity was detected in 12 supplements, antagonistic bio-activity was detected in 16 and partial antagonistic bio-activity was detected in 10. A further group of supplements (7) did not present androgenic bio-activity when tested alone but enhanced the androgenic agonist bio-activity of dihydrotestosterone when combined. The developed assays offer advantages in detection of known, unknown and low-level mixtures of endocrine disruptors over existing analytical screening techniques. For the detection and identification of constituent hormonally active compounds the combination of biological and physio-chemical techniques is optimal. © 2010 Elsevier B.V.

Gallo P.,Istituto Zooprofilattico Sperimentale del Mezzogiorno | Fabbrocino S.,Istituto Zooprofilattico Sperimentale del Mezzogiorno | Dowling G.,The State Laboratory | Salini M.,Istituto Zooprofilattico Sperimentale del Mezzogiorno | And 3 more authors.
Journal of Chromatography A | Year: 2010

HPLC with fluorescence detection is considered for confirmatory analysis of group B veterinary drugs by the European Union legislation. A procedure for confirming the presence of anti-inflammatory non-steroidal drug (NSAID) residues in bovine milk by reversed phase high-performance liquid chromatography with fluorescence detection is herein described. The native fluorescence of nine drugs belonging to different NSAID sub-classes, namely flurbiprofen, carprofen, naproxen, vedaprofen, 5-hydroxy-flunixin, niflumic acid, mefenamic acid, meclofenamic acid and tolfenamic acid, allowed for detection in bovine milk down to 0.25-20.0 μg/kg. Confirmation of the nine NSAIDs is attained by fluorescence detection at characteristic excitation and emission wavelengths. The procedure described is simple and selective. Limits of quantification (LOQs) ranging between 0.25 and 20 μg/kg were measured; satisfactory trueness and within-laboratory reproducibility data were calculated at LOQ spiking levels, apart from 5-hydroxy-flunixin. The procedure developed is used in our laboratory for confirmation of each one of the above mentioned NSAIDs in bovine milk, to support results after HPLC quantitative analysis with UV-vis detection. © 2010 Elsevier B.V.

Malone E.M.,The State Laboratory | Malone E.M.,Queens University of Belfast | Elliott C.T.,Queens University of Belfast | Kennedy D.G.,Agri Food and Biosciences Institute of Northern Ireland | Regan L.,The State Laboratory
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2010

A rapid liquid chromatographic-tandem mass spectrometric (LC-MS/MS) multi-residue method for the simultaneous quantitation and identification of sixteen synthetic growth promoters and bisphenol A in bovine milk has been developed and validated. Sample preparation was straightforward, efficient and economically advantageous. Milk was extracted with acetonitrile followed by phase separation with NaCl. After centrifugation, the extract was purified by dispersive solid-phase extraction with C18 sorbent material. The compounds were analysed by reversed-phase LC-MS/MS using both positive and negative ionization and operated in multiple reaction monitoring (MRM) mode, acquiring two diagnostic product ions from each of the chosen precursor ions for unambiguous confirmation. Total chromatographic run time was less than 10 min for each sample. The method was validated at a level of 1 μg L-1. A wide variety of deuterated internal standards were used to improve method performance. The accuracy and precision of the method were satisfactory for all analytes. The confirmative quantitative liquid chromatographic tandem mass spectrometric (LC-MS/MS) method was validated according to Commission Decision 2002/657/EC. The decision limit (CCα) and the detection capability (CCβ) were found to be below the chosen validation level of 1 μg L-1 for all compounds. © 2010 Elsevier B.V. All rights reserved.

A sensitive and selective method for the simultaneous determination of non-steroidal anti-inflammatory drugs in bovine plasma was developed. Confirmatory analysis was carried out by liquid chromatography coupled with an electrospray ionisation tandem mass spectrometer (LC-ESI-MS/MS). Target compounds were acidified in plasma and extracted with acetonitrile. Sodium chloride was added to assist separation of the plasma and acetonitrile mixture. The acetonitrile extract is then subjected to liquid-liquid purification by the addition of hexane. Accuracy of the methods in plasma was between 93 and 102%. The precision of the method for the basic NSAIDs in plasma expressed as % RSD, for the within-laboratory reproducibility was less than 10%. Decision limit (CCα values) and detection capability (CCβ) values were established. The methods were validated according to Commission Decision 2002/657/EC. © 2011 Elsevier B.V.

Malone E.,The State Laboratory | Malone E.,Queens University of Belfast | Elliott C.,Queens University of Belfast | Kennedy G.,Agri Food and Biosciences Institute of Northern Ireland | And 2 more authors.
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2011

A simple, new method permitting the simultaneous determination and confirmation of trace residues of 24 different growth promoters and metabolites using liquid chromatography-mass spectrometry was developed and validated. The compounds were extracted from bovine tissue using acetonitrile; sodium sulphate was also added at this stage to aid with purification. The resulting mixture was then evaporated to approximately 1ml and subsequently centrifuged at high speed and an aliquot injected onto the LC-MS/MS system. The calculated CCα values ranged between 0.11 and 0.46 μgkg-1; calculated CCβ were in the range 0.19-0.79 mgkg-1. Accuracy, measurement of uncertainty, repeatability and linearity were also determined for each analyte. The analytical method was applied to a number of bovine tissue samples imported into Ireland from third countries. Levels of progesterone were found in a number of samples at concentrations ranging between 0.28 and 30.30 μgkg-1. Levels of alpha- and beta-testosterone were also found in a number of samples at concentrations ranging between 0.22 and 8.63 μgkg-1 and between 0.16 and 2.08 μgkg-1 respectively. © 2011 Taylor & Francis.

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