Determination of organochlorine pesticide residues in rice by gas chromatography tandem mass spectrometry

A simple and sensitive method for the determination of organochlorine pesticide residues namely HCH isomers (alpha, beta, gamma (lindane) & delta), DDT isomers (2,4-DDE, 4,4-DDE, 2,4-DDD, 4,4-DDD, 2,4-DDT & 4,4DDT), endosulfan (alpha and beta), endosulfan sulfate, heptachlor, heptachlor epoxide aldrin, dieldrin, endrin, chlorthalonil, chlordane & dicofol in rice grains by gas chromatography –tandem mass spectrometry (GC-MS/MS) was developed. The organochlorine residues were extracted from homogenized samples initially with water followed by acetonitrile and cleaned up by using dispersive solid phase extraction which is based on QuEChERS (quick, easy, cheap, rugged and safe ) method , finally the organo chlorine residues were separated by DB-5MS gas chromatography capillary column and quantified through tandem mass spectrometry(GC-MS/MS) with Electron ionization source. Multiple reaction monitor mode (MRM) method was used for quantification and confirmation. Recoveries were checked at two fortification levels of 0.1-0.05mg/kg (n=6). The results showed that the mean recoveries for the fortified samples were in the range of 83-110% and %RSD in the range of 5.7 -14.8 for all compounds. Thus the developed analytical method was successfully used to analyze organochlorine pesticide residues in routine rice samples.