Rapid determination of pesticide residues in Chinese materia medica using QuEChERS sample preparation followed by gas chromatography–mass spectrometry

Abstract

Pesticide residue analysis plays an important role in the quality control of Chinese materia medica. This paper reports the development and validation of an analytical method for the quantitative determination of the residues of 39 pesticides in 12 different matrices of Chinese materia medica. Sample preparation utilized the QuEChERS method with acetonitrile:1% aqueous acetic acid (9:1, v/v) as extraction solvent followed by sample clean-up by dispersive solid phase extraction using primary secondary amine sorbent and graphitized carbon black. Extracts were then analysed by gas chromatography coupled with electron impact mass spectrometry in the selected ion monitoring mode. Limit of detection (LOD) and limit of quantitation (LOQ) values were in the ranges 0.5–50ng/g and 1–100ng/g, respectively. The recoveries of the 39 pesticides were in the range 75–112% with precision (as relative standard deviation, RSD) <15%. The results show that the modified QuEChERS method allows rapid and sensitive analysis of multiple pesticide residues in Chinese materia medica.