Simultaneous Determination of 18 Pesticide Residues including Pyrethroids in Soils by Gas Chromatography-Mass Spectrometry with Accelerated Solvent Extraction

A method was developed for simultaneous determination of 18 pesticide residues in soils, including hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs) and other 10 kinds of pyrethroid. The soil samples were distilled with Accelerated Solvent Extraction (ASE) and extracted by hexane-acetone-H₃PO₄ at extraction temperature of 100℃ and pressure of 10.3 MPa. The distilled solutions were purified by solid phase extraction (SPE). The purified solutions were injected into Gas Chromatography-Mass Spectrometry (GC-MS) by using programmed temperature vaporization (PTV) and large volume injector (LVI). If the spiked level was 10-20 μg/kg, the recoveries of target compounds were 80.55%-96.33% and the relative standard deviations (RSDs, n=6) were 3.21%-7.34%. If the spiked level was 20-40 μg/kg, the recoveries were 80.55%-103.76% and RSDs (n=6) were 2.56%-5.78%. If the spiked level was 40-80 μg/kg, the recoveries were 81.56%-95.38%, RSDs(n=6) were 2.19%-5.88%. The method detection limits were 0.11-2.38 μg/kg, RSDs (n=3) were 4.94%-8.74% for real samples. The method is simple and rapid with high sensitivity making it suitable for simultaneous determination of residues of benzex and DDTs and pyrethroid in soils.