title: Simultaneous analysis of endosulfan, chlorpyrifos, and their metabolites in natural soil and water samples using gas chromatography-tandem mass spectrometry.
abstract: Analysis of endosulfan, chlorpyrifos, and their nonpolar metabolites in extracts from environmental aqueous and soil samples was performed using a gas chromatography-tandem mass spectrometry (GC-MS/MS) technique. Full-scan GC-MS analysis showed poor sensitivity for some of the metabolites (endodiol and endosulfan ether). A multisegment MS/MS method was developed and MS/MS parameter isolation time, excitation time, excitation voltage, and maximum excitation energy were optimized for chosen precursor ions to enhance selectivity and sensitivity of the analysis. The use of MS/MS with optimized parameters quantified analytes with significantly higher accuracy, and detection limits were lowered to ~1/6th compared with the full-scan method. Co-eluting compounds, chlorpyrifos and chlorpyrifos oxon, were also analyzed successfully in the MS/MS mode by choosing exclusive precursor ions. Analysis of soil and water phase samples from contaminated soil slurry bioreactors showed that the MS/MS method could provide more reliable estimates of these pesticide and metabolites (especially those present in low concentrations) by annulling interferences from soil organic matter.
authors.affiliation: Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur, 208016, India. mktiwari@iitk.ac.in
authors.forename: Manoj K
authors.initials: MK
authors.lastname: Tiwari
authors.forename: Saumyen
authors.initials: S
authors.lastname: Guha
mesh_terms: D004390:Chlorpyrifos / Q000032:analysis*; D004726:Endosulfan / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D005618:Fresh Water / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D057230:Limit of Detection; D008956:Models, Chemical; D010575:Pesticides; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis*; D053719:Tandem Mass Spectrometry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D010575:Pesticides; D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D004390:Chlorpyrifos; D004726:Endosulfan