title: A sensitive LC-MS/MS method for measurement of organophosphorus pesticides and their oxygen analogs in air sampling matrices.
abstract: A rapid liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed for determination of levels of the organophosphorus (OP) pesticides chlorpyrifos (CPF), azinphos methyl (AZM), and their oxygen analogs chlorpyrifos-oxon (CPF-O) and azinphos methyl-oxon (AZM-O) on common active air sampling matrices. XAD-2 resin and polyurethane foam (PUF) matrices were extracted with acetonitrile containing stable-isotope labeled internal standards (ISTD). Analysis was accomplished in Multiple Reaction Monitoring (MRM) mode, and analytes in unknown samples were identified by retention time (±0.1 min) and qualifier ratio (±30% absolute) as compared to the mean of calibrants. For all compounds, calibration linearity correlation coefficients were ≥0.996. Limits of detection (LOD) ranged from 0.15-1.1 ng/sample for CPF, CPF-O, AZM, and AZM-O on active sampling matrices. Spiked fortification recoveries were 78-113% from XAD-2 active air sampling tubes and 71-108% from PUF active air sampling tubes. Storage stability tests also yielded recoveries ranging from 74-94% after time periods ranging from 2-10 months. The results demonstrate that LC-MS/MS is a sensitive method for determining these compounds from two different matrices at the low concentrations that can result from spray drift and long range transport in non-target areas following agricultural applications. In an inter-laboratory comparison, the limit of quantification (LOQ) for LC-MS/MS was 100 times lower than a typical gas chromatography-mass spectrometry (GC-MS) method.
authors: a Department of Environmental and Occupational Health Sciences , University of Washington School of Public Health , Seattle , Washington , USA.
authors: Jenna L
authors: JL
authors: Armstrong
authors: Russell L
authors: RL
authors: Dills
authors: Jianbo
authors: J
authors: Yu
authors: Michael G
authors: MG
authors: Yost
authors: Richard A
authors: RA
authors: Fenske
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002853:Chromatography, Liquid / Q000379:methods*; D004784:Environmental Monitoring / Q000379:methods*; D057230:Limit of Detection; D063086:Organothiophosphates / Q000032:analysis*; D010575:Pesticides / Q000032:analysis*; D011137:Polystyrenes / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013997:Time Factors
chemical_list: D000393:Air Pollutants; D063086:Organothiophosphates; D010575:Pesticides; D011137:Polystyrenes; D011140:Polyurethanes; C028279:polyurethane foam; C003771:Amberlite XAD-2 resin