Determination of Residues of 30 Forbidden Pesticides in Salvia Miltiorrhiza by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry with Solid Phase Extraction

A method for the determination of residues of 30 forbidden pesticides in Salvia miltiorrhiza by ultra-high performance liquid chromatography-tandem mass spectrometry with solid phase extraction (SPE-UHPLC-MS/MS) was proposed. Sample powder was soaked in 0.5% (volume fraction) acetic acid solution and then oscillated for extraction with acetonitrile, and the extract was purified by ProElut SMC extraction cartridge. Spursil C₁₈ column (100 mm×2.1 mm, 3.0 μm) was used as stationary phase, and the 30 forbidden pesticides were separated under gradient elution procedure. The analytes were scanned by electrospray ion source with positive ion mode, and detected by multi-reaction monitoring mode, and the matrix matching mixed standard solutions were used to draw working curves, with external standard method for quantitation. It was shown that linear relationships between the mass concentrations and corresponding quantitative ion peak areas of 30 forbidden pesticides were kept in definite ranges, with lower limits of determination (10S/N) in the range of 1-5 μg·L^-1. Test for recovery was made on the blank sample by standard addition method at 3 concentration levels, giving results in the range of 75.0%-120%, and RSDs (n=6) of the determined values ranged from 1.2% to 6.0%. This method was applied to analysis of the sold Salvia miltiorrhiza samples. The detection amounts of fonofos and sulfotep in one batch of sample were 1.16 μg·kg^-1 and 0.37 μg·kg^-1, respectively, and other forbidden pesticides were not detected.