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Ovokeroye A. Abafe Pumza Gatyeni Lungile Matika 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2020,37(3):438-450
ABSTRACTAn ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) based multiclass multi-residue method for the simultaneous analysis of 5 polyether ionophores, 4 tetracycline and 10 sulfonamides in animal and aquaculture fish tissues was developed and validated. Sample extraction and clean-up were based on a modified QuEChERS method. The method was validated using an in-house validation based on performance characteristics modified from Commission Decision 2002/657/EC. Both matrix effect and uncertainties associated with sample preparation and instrumental analysis were minimised by the use of matrix-matched calibrations. Recoveries of analytes were generally satisfactory and typically fell between 80% and 113%. The repeatability and intermediate reproducibility measured as relative standard deviations were in most cases less than 15% (n = 63). The decision limit (CCα) and detection capability (CCβ) ranged from 110.7 to 125.8 and 121.5 to 151.7 µg kg?1 for tetracyclines, 113.4 to 118.3 and 116.8 to 126.5 µg kg?1 for sulfonamides and 50.8 to 52.4 and 51.5 to 55.6 µg kg?1 for polyether ionophores, respectively. The method displayed its fitness for purpose through satisfactory results obtained in international proficiency testing schemes. The method was applied to animal and aquaculture fish tissues obtained from different sources in South Africa. Polyether ionophores were predominantly detected in samples in the range 4.26–290.10 µg/kg. Oxytetracycline was found in one porcine liver sample; however, none of the targeted analytes were present above the detection limit in the aquaculture samples. 相似文献
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Ovokeroye Akpojevwe Abafe Pumza M. Gatyeni Tlou Chokwe 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2018,35(3):458-466
A simple and accurate ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the first time as a confirmatory method for the simultaneous determination of stilbenes – hexestrol and diethylstibestrol in serum. Extraction was based on a simple acid denaturation of protein followed by liquid–liquid extraction using methyl tert butyl ether. Extracts were directly injected into the UHPLC-MS/MS without further purification. Excellent recoveries in the range 82–99% and 91–128% were obtained for hexestrol and diethylstibestrol, respectively. Both within-day repeatability and between-day reproducibility were generally satisfactory with RSD <20%. The linearity of the internal standard based matrix-matched calibration curve measured as the coefficient of regression (r2) was generally >0.99 for both hexestrol and diethylstibestrol. Both matrix effect and uncertainties associated with sample preparation and instrumental analysis were significantly reduced with the use of a deuterated compound (hexestrol-d4) as internal standard. The LOD and LOQ were 0.09 and 0.08 ng/ml, and 0.28 and 0.25 ng/ml, respectively, for hexestrol and diethylstibestrol. The method was found to be suitable for the simultaneous determination of hexestrol and diethylstibestrol in serum. 相似文献
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