Determination of Residues of 30 Banned Pesticides in Angelica Sinensis Radix by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry with Different Pretreatment Methods

Angelica sinensis Radix sample was pretreated by QuEChERS method and solid phase extraction method, and the solution was concentrated and diluted with 60% (φ) acetonitrile solution. The residues of 30 banned pesticides were simultaneously determined by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Agilent ZORBAX SB-C₁₈ column (100 mm×2.1 mm, 3.5 μm) was used as the stationary phase, and 0.1% (φ) formic acid solution containing 5 mmol·L^-1 ammonium formate-acetonitrile were used as the mobile phase system for gradient elution. Electrospray ionization with positive ion scanning and multiple reaction monitoring mode were used in the mass spectrometry analysis. Matrix matching method was used to draw working curves, and external standard method was used for quantification. It was shown that almost all the pesticides had matrix effect except aldicarb. Linear relationships between values of mass concentration and peak area of quantitative ion pairs of 30 banned pesticides were kept in definite ranges, with detection limits in the ranges of 0.13-15.06 μg·kg^-1 (QuEChERS method) and 0.13-14.77 μg·kg^-1 (solid phase extration method). RSDs (n=6) of the determined values of 30 banned pesticides in the matrix matching mixed standard solutions were in the ranges of 1.4%-12% (QuEChERS method) and 1.0%-13% (solid phase extration method). Values of spiked recovery of 30 banned pesticides in negative sample were in the ranges of 60.4%-140% (QuEChERS method) and 61.0%-144% (solid phase extraction method). This method was used to screen the residues of banned pesticides in 23 batches of Angelica sinensis Radix samples, and phorate-sulfoxide was detected in 2 batches of the samples, with detection amounts in the range of 0.016 0-0.019 7 mg·kg^-1, and the results of QuEChERS method and solid phase extraction method were basically consistent.