Determination of Organochlorine Pesticide Residues in Chinese Herbal Tea Granule by Accelerated Solvent Extraction Combined with Gas Chromatography-Negative Chemical Ionization-Mass Spectrometry

KeyWord:Chinese herbal tea  organochlorine pesticide  gas chromatography-negative chemical ionization-mass spectrometry  accelerated solvent extraction  residue

Abstract:

      A method was developed for the determination of organochlorine pesticide residues in Chinese herbal tea granule by accelerated solvent extraction combined with gas chromatography-negative chemical ionization-mass spectrometry(ASE/GC-NCI-MS)ª±The samples were extracted with ASE for 10 min¡Á3 times using hexane-dichloromethane(1¡Ã1) as solvent at temperature of 100 ¡æ and pressure of 10 MPa.The extracts were purified by solid phase extraction using a SampliQ Silica column,concentrated with a gentle stream of nitrogen,and then separated on a DB-1MS column(30 m¡Á0.25 mm¡Á 0.1 ¦Ìm).The quantitative analysis of 25 organochlorine pesticides was carried out by GC-NCI-MS under selected ion monitoring mode.The calibration curves of 25 organochlorine pesticides were linear in the range of 1-500 pg,with correlation coefficients more than 0.999.The limits of detection and limits of quantitation were in the ranges of 1.0-34.4 pg/g and 3.4-114.6 pg/g,respectively.The spiked recoveries ranged from 86% to 105%.The method was applied in the determination of the Chinese herbal tea granule samples with different batches from different manufactures,and none of the 25 organochlorine pesticides was detected.The method was sensitive and efficient,and could meet the requirement for the quality control of organochlorine pesticide residues in Chinese herbal tea granule.