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(T/EH110) Rapid multiresidue methods for the determination of pesticides in soil and air. Sanchez-Brunete, C.1, Castro, J.1, Perez, R.A.1, Tadeo, J.L.1, 1 ABSTRACT- Pesticides are widely used in horticultural crops applied to soil, in some cases, or deposited on this compartment after their application, where they are subjected to different processes that will determine their fate in the environment. The aim of this work was to develop rapid multiresidue methods for the pesticide analysis in soil and air. Residues in soil are determined by a procedure based on the sonication extraction of pesticides from a certain amount of soil placed in small columns, using ethyl acetate as the extractant solvent. The pesticides selected for their determination in soil were lindane, heptachlor, endosulfan, endosulfan-sulfate, tetradifon, chlorpyrifos, Key words: analysis, pesticides, soil, air |
-cyhalothrin, acrinathrin and pendimethalin. Four of these pesticides belonging to different chemical groups (lindane, pendimethalin, chlorpyrifos and endosulfan) were also analysed in air by headspace solid-phase microextraction (SPME). Pesticides were determined by gas chromatography with electron capture detection (GC-ECD) and their identity was confirmed by gas chromatography coupled with mass spectrometry. The SPME procedure allowed the determination of pesticides in air with good repeatability (R.S.D. lower than 20%) and sensibility (detection limits near 1 ng/l).The average recovery through the method obtained for these compounds in soil varied from 87 % to 108 % with a relative standard deviation between 2 % and 11 %. The described procedure is simple, rapid and requires a small amount of soil sample (5 g) and low solvent volumes (10 ml). This method was applied to the analysis of soil from commercial Spanish tomato orchards, sampled after harvest, and some pesticides widely used in this crop were detected in the range of 0.01 to 0.15 
g/g.