Analysis of dialkylphosphate transformation products of organophosphorus pesticides in biological and environmental sample

Dialkylphosphate compounds are formed in the breakdown of organophosphorus pesticides (OPs). Analysis of these metabolites in biological and environmental samples allows measurement of OP exposure. Measurement of these compounds in human urine is particularly useful in monitoring of OP exposure in agricultural workers. Published methods for the analysis of dialkylphosphate (DAP) metabolites are described, along with their limitations.;One published procedure for DAP analysis in human urine was used in the detection of worker exposure to the OP Diazinon. Measurements of external dermal and respiratory exposure, through the use of passive dosimeters and analysis of air Diazinon concentrations, were compared to DAP results from per- and post-shift urine samples. The type of application equipment used by the applicators determined both the magnitude and distribution of Diazinon exposure. While urinary DAP concentrations were correlated with morning Diazinon exposures, many difficulties were encountered in the urine analysis.;To overcome the drawbacks of published methods, a new procedure for urine DAP analysis was developed. The method relies on disposable solid-phase extraction cartridges for separation of the DAPs from the urine matrix, the injector-port derivatizing reagent tetrabutylammonium hydroxide, and gas chromatographic analysis using wide-bore capillary columns and flame photometric detection. The procedure is faster, more consistent, and less complicated than published methods, with similar or better recoveries and sensitivities.;The serviceability of the new procedure was tested in the analysis of human urine from subjects in two exposure studies. OP exposure to greenhouse workers and peach harvesters was examined. Large numbers of samples were analyzed rapidly, and no analytical difficulties were encountered. The method, with slight modifications, was also applied to avian excreta, and was successful in the detection of significant OP exposures in orchard avian populations. The time course of DAP excretion after dermal dosing was examined in rabbits through urine and plasma analysis. The majority of DAP urine excretion was complete within 30 hours, and plasma concentrations were no longer detectable 24 hr after dosing. DAP concentrations in fogwater were also measured, and were found to correlate well with fog OP content.