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Abstract: A simple and easy-to-use extraction method for aqueous samples based on hollow fibre-supported liquid membrane (HF-SLM) followed by liquid chromatography–mass spectrometry/mass spectrometry (LC–MS/MS) was developed to determine ivermectin and transformation products, the monosaccharide (TP1) and the aglycon of ivermectin (TP2). The proposed method attained enrichment factors up to 80, after optimising parameters, such as fibre length, organic solvent, stirring speed, salt level, pH in samples/fibre, extraction time and fibre emptying technique. Method validation with tap and lake water samples provided good linearity and detection limits of 0.2, 1.6 and 0.9μg/l for ivermectin, TP1 and TP2 in lake water with RSD below 15%. [Copyright &y& Elsevier]

Abstract: Methods are reported for determining six sulfonamides used as veterinary drugs in water and soil samples. Analytes are isolated from water samples by solid-phase extraction on HBL cartridges and pre-concentration factors of up to 250 were obtained. Soil samples are treated using microwave-assisted extraction of analytes with acetonitrile and further clean up by solid-phase extraction. Determination is carried out by high-performance liquid chromatography using fluorimetric detection with precolumn derivatization with fluorescamine. The separation of the derivatized sulfonamides is performed on an octadecyl column using binary gradient elution with acetate buffer/acetonitrile mixtures. For water analysis, the detection limits of the whole process are in the low nanogram per liter level and recovery rates range from 70 to 104%, with standard deviations 2–11%. For soil analysis, extraction efficiency is evaluated using three soil samples with different physicochemical characteristics. Recovery rates range from 60 to 98% and detection limits are between 1 and 6ngg−1. [Copyright &y& Elsevier]