DETERMINATION OF MULTI-PESTICIDE RESIDUES IN THE GREEN TEA PRODUCTS BY GC/MS

Abstract

    In this study, the Gas Chromatography-Mass Spectrometry (GC/MS) method to determine eight pesticides (Dimethoate, Diazinon, Fenitrothion, Endosulfan sulfat, Permethrin, Cyfluthrin, Fenvalerate, and Deltamethrin) in products made from green tea has been developed. The optimization of GC/MS condition based on resolution and stability for analysis of pesticide residues were investigated. The calibration curves for all pesticides were prepared in range of 625-20000 ng/mL and the linearity of the calibration curves yielded determination correlation coefficient (R2) ≥ 0.997. The spike recoveries were carried out using blank samples spike with all analystes at tow levels, the results demonstrated that all pesticides were recovered within the range of 86.6-94.2% with a relative standard deviation (RSD) ≤ 7.51% at concentration of 1250 ng/mL and ≤ 4.83 % at concentration of 20000 ng/mL. The limit of detection (LOD) was from 22 to23 ng/mL and limit of quantification (LOQ) was from 66-113 ng/mL for eight pesticides. The method enables to determine pesticides at low ng/mL in some products made from green tea in Vietnam.

Từ khóa: Hóa chất bảo vệ thực vật, chè, sắc ký khí, khối phổ, GC/MS.