Determination of Residues of 5 Acaricides in Soil Environment by GC-MS/MS after Automatic Soxhlet Extraction and Solid Phase Extraction

5 g of the pretreated soil sample was put into the Soxhlet extractor and extracted with dichloromethane as extraction solvent. The extracted solution was purified by HLB solid phase extraction small column and eluted with methanol. Then the all eluate collected was blown to nearly dry with nitrogen and made its volume up to 1 mL with methanol. The solution was analyzed by gas chromatography-tandem mass spectrometer in multi-reaction monitoring mode, and external standard method was used for quantitative analysis. As shown by the results, linear ranges of the standard curves of oxythane, methacrifos, chinomethionate, chlorfenson and chlorobenzilate were 0.01-5.0 mg·L^-1, with detection limits (3S/N) of 0.004, 0.006, 0.008, 0.010 mg·kg^-1 and 0.008 mg·kg^-1, respectively. Values of recovery of 5 acaricides at 3 spiked concentration levels were in the range of 84.8%-99.6% on the blank soil sample, and RSDs (n=6) of the determined values were ranged from 2.1% to 4.0%. This method was used to analyze the 5 actual soil samples, and oxythane, chinomethionate, chlorfenson and chlorobenzilate were detected, with detection amounts in the range of 0.003-0.007 mg·kg^-1.