Analysis of trace levels of sulfonamides in surface water and soil samples by liquid chromatography-fluorescence

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 highperformance liquid chromatography using fluorimetric detection with precolumn derivatization with fluorescamine. The separation of the derivatized sulfonarnides 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 I and 6 ng g(-1). (c) 2007 Elsevier B.V. All rights reserved.