DEVELOPMENT OF MATRIX SOLID PHASE DISPERSION (MSPD) METHOD FOR THE DETERMINATION OF PESTICIDE RESIDUES IN TEA BY LC-MS

Abstract

     A matrix solid-phase dispersion (MSPD) method was developed to extract and determine methomyl and imidacloprid in tea products using the mixture of silica gel and zirconia-modified activated charcoal as dispersant sorbent and clean-up sorbent. The best results were obtained using the mixture of CH3CN:CH3COOC2H5:C6H5CH3 (13.5:1.5:5.0, v/v/v) as eluting solvent. The procedure has got the best recoveries for two pesticides. Mean recoveries from seven replicates ranged from 87.5% to 103% with relative standard deviation between 4.8% and 10.4%. The method detection limit (MDL) was in 0.013mg/kg and 0.058mg/kg for methomyl and imidacloprid, respectively. The sample preparation time is about 40 min. This method is more environmental-friendly with only 30ml solvent consumption.