A Comparative Study of Methods for Detection of Pesticide Residues in Tea

The samples were extracted by Accelerated Solvent Extraction(ASE) and high-speed homogenate extraction,and purified by Solid Phase Extraction(SPE) and Gel Permeation Chromatography(GPC),then determined by Gas Chromotography-Mass Spectrometry(GC-MS) and Gas Chromatography(GC).This paper focused on the method for determination of residues of 32 kinds of pesticides,in which 14 kinds are need to detection in tea product,and 13 kinds are high toxic pesticides and 5 kinds are dimethrin pesticides.Two extracting methods,purifications,and,detection by two instruments are used on every sample,meanwhile,recovery testings are provided respectively.The result showed that when the concentration of spike was 0.10 mg/kg,the recoveries and RSD were: 81.00%～119.80% and 1.10～5.42 as general method extraction and SPE purification used;76.47%～93.45% and 3.43～7.34 as general extraction and gel chromatography purification used;80.12%～110.30% and 1.37～5.32 as ASE rapid extraction and SPE purification used;76.45%～93.56% and 2.56～7.98 as ASE rapid extraction and gel chromatography purification used.The Method Detection Limit(MDL) were MSD in the range of 0.079～14.40 μg/kg and FPD/ECD in the range of 0.24～98.0 μg/kg.The combinations of different means in this paper contains the advantages of high-sensitivity,high precision,rapidity,and wide linearity,which meet the determination of pesticide multi-residues in tea.