title: Quantification of dialkylphosphate metabolites of organophosphorus insecticides in human urine using 96-well plate sample preparation and high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry.
abstract: Organophosphorus (OP) pesticides kill by disrupting a targeted pest's brain and nervous systems. But if humans and other animals are sufficiently exposed, OP pesticides can have the same effect on them. We developed a fast and accurate high-performance liquid chromatography-tandem mass spectrometry method for the quantitative measurement of the following six common dialkylphosphate (DAP) metabolites of organophosphorus insecticides: dimethylphosphate (DMP), dimethylthiophosphate (DMTP), dimethyldithiophosphate (DMDTP), diethylphosphate, (DEP), diethylthiophosphate (DETP), and diethyldithiophosphate (DEDTP). The general sample preparation included 96-well plate solid phase extraction using weak anion exchange cartridges. The analytical separation was performed by high-performance liquid chromatography with a HILIC column. Detection involved a triple quadrupole mass spectrometer with an ESI probe in negative ion mode using multiple reaction monitoring. Repeated analyses of urine samples spiked at 150, 90 and 32 ng/mL with the analytes gave relative standard deviations of less than 22%. The extraction efficiency ranged from 40% to 98%. The limits of detection were in the range of 0.04-1.5 ng/mL. The throughput is 1152 samples per week, effectively quadrupling our previous throughput. The method is safe, quick, and sensitive enough to be used in environmental and emergency biological monitoring of occupational and nonoccupational exposure to organophosphates.
authors.affiliation: Centers for Disease Control and Prevention, National Center for Environmental Health, Division of Laboratory Sciences, Atlanta, GA, USA.
authors.forename: Martins S
authors.initials: MS
authors.lastname: Odetokun
authors.forename: M Angela
authors.initials: MA
authors.lastname: Montesano
authors.forename: Gayanga
authors.initials: G
authors.lastname: Weerasekera
authors.forename: Ralph D
authors.initials: RD
authors.lastname: Whitehead
authors.forename: Larry L
authors.initials: LL
authors.lastname: Needham
authors.forename: Dana Boyd
authors.initials: DB
authors.lastname: Barr
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004781:Environmental Exposure; D006801:Humans; D007306:Insecticides / Q000652:urine*; D057230:Limit of Detection; D016273:Occupational Exposure; D009943:Organophosphorus Compounds / Q000652:urine*; D011786:Quality Control; D012015:Reference Standards; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D007306:Insecticides; D009943:Organophosphorus Compounds