Multiresidue Analysis of Pesticides in Soil by Liquid-Solid Extraction Procedure

A multiresidue method for simultaneous determination of four pesticides (diazinon, acetochlor, aldrine and carbofuran) belonging to different pesticide groups, extracted from soil samples, is described. The method presented is based on liquid-solid extraction (LSE) and determination of pesticides, i.e. the pesticides were extracted by methanol-acetone mixture, purified on florisil column and eluted by ethyl acetate-acetone mixture. Optimization of the main parameters affecting the LSE procedure, such as the choice of purification sorbent, as well as the elution solvent and its volume, were investigated in details and optimized. Also, validation of the proposed method was done. Gas chromatography-mass spectrometry (GC-MS) was used for detection and quantification of the pesticides studied. Relative standard deviation (RSD) and recovery values for multiple analysis of soil samples fortified with 30 μg/kg of each pesticide were below 8% and higher than 89%, respectively. Limits of detection (LOD) for all the compounds studied were less than 4 μg/kg.