A sensitive LC-MS/MS method for measurement of organophosphorus pesticides and their oxygen analogs in air sampling matrices.
Armstrong JL; Dills RL; Yu J; Yost MG; Fenske RA
J Environ Sci Health, Part B, Pestic Food Contam Agric 2014 Feb; 49(2):102-108
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.
Analytical-methods; Organo-phosphorus-compounds; Organo-phosphorus-pesticides; Air-sampling; Resins; Polyurethane-foams; Monitoring-systems; Sampling; Agriculture; Agricultural-chemicals; Organic-compounds; Organo-phosphorus-compounds; Pesticides;
Author Keywords: Air monitoring; organophosphorus; pesticide; drift; oxon; polyurethane foam; XAD resin
Jenna L. Armstrong, Department of Environmental and Occupational Health Sciences, University of Washington School of Public Health, box 357234, Seattle, WA 98195
Agriculture, Forestry and Fishing
Journal of Environmental Science and Health. Part B: Pesticides, Food Contaminants, and Agricultural Wastes
University of Washington