Determination of Residues of 5 Succinate Dehydrogenase Inhibitor Fungicides in Soil by Gas Chromatography-Tandem Mass Spectrometry

A method for simultaneous determination of residues of 5 succinate dehydrogenase inhibitor fungicides in soil, including fenfuram, penthiopyrad, benodanil, mepronil and furametpyr, was proposed by gas chromatography-tandem mass spectrometry(GC-MS/MS) after accelerated solvent extraction (ASE) combined with QuEChERS automatic sample preparation system purification. 10.00 g of the dried and sieved soil sample was taken, and 5 g of diatomite was added. Affer mixing uniform, the mixture was placed in the extraction tank, and extracted with a mixed solution of hexane and ethyl acetate at a volume ratio of 1∶2. The extract was concentrated to 10 mL on a rotary evaporator and transferred to the purification tube of the QuEChERS automatic sample preparation system. The mixture was oscillated for 5 min and centrifuged at a rotational speed of 8 000 r·min⁻¹ for 5 min. 2 mL of supernatant was blown to near drynesss by nitrogen at 50 ℃ in water bath, and made its volume up to 1 mL with hexane. Targets in the solution was separated on a Rxi-5Sil MS chromatographic column according to the column heating program. Multiple reaction monitoring (MRM) mode was adopted in mass spectrometry analysis, and the external standard method was used for quantitative analysis. As shown by the results, linear relationships between the corresponding peak areas and mass concentrations of 5 succinate dehydrogenase inhibitor fungicides were found within 0.005-0.1 mg·L⁻¹, with detection limits (3S/N) in the range of 0.000 7-0.001 1 mg·kg⁻¹. Test for recovery was made by the standard addition method, giving results in the range of 89.6%-110%, with RSDs (n=6) of the determined values less than 5.0%. This method was used for the analysis of 5 samples of planting soil for different crops, and 5 succinate dehydrogenase inhibitor fungicides were not detected.