Determinnation of the residues of α-endosulfan and pyrethriods in tea by gas chromatography with sulphuric acid clean-up

A new method for clean-up and determining residues of α-endosulfan and pyrethroids in tea was discussed.The method uses acetonitrile to extract residues of the pesticides in tea samples,followed by clean up using sulphuric acid-ethanol and determination using gas chromatography (GC-ECD).Average fortified recoveries in samples were found at the range of 81.6%-105.9% at fortified levels from 0.005 mg/kg to 0.5 mg/kg with relative standard deviations of 0.52%-13.0%.The limit of quantification (LOQ) of pyrethriods and for blank α-endosulfan in blank samples was 0.005 mg/kg.No obvious interferences were found by using this method.It needs no special instrument and can meet the requirements of pesticide residue analysis on accuracy,sensitivity and precision.It is suitable for the residue analysis of pyrethriods andα-endosulfan residue in tea.