Mechanized System for Liquid Chromatographic Determination of 4-Nitrophenol and Some Other Phenolic Pesticide Metabolites in Urine

Abstract

Abstract Protecting the health of workers who are exposed to pesticides is of concern. One helpful approach is to periodically analyze the urine of such workers for metabolites of those pesticides encountered in the working environment. Therefore, an analytical system for several urinary pesticide metabolites, which incorporates a high degree of mechanization, has been developed. Urine samples (ca 8 ml) are placed in a sampler module. An acid hydrolysis step, a steam distillation step, and a combined liquid chromatographic separation and UV absorption determinative step are performed automatically, except for the need for an operator to turn a loop valve injector for the liquid chroma tograph at an exact time after the start of sampling each sample. At the slowest rate, a sample is analyzed every 24 min with a lower limit of detectability from 1 to 2 ppm added 4-nitrophenol in urine. Acid hydrolysis is included to cleave urinary conjugates of the analyte(s) of metabolic origin; steam distillation provides considerable cleanup. The method, with minor adjustment of chromatographic conditions, also responds to <5 ppm each of the other phenols derivable from the below-named (and some other) pesticides. Alternative conditions permit detection of <1 ppm 1-naphthol. Exact limits lower than the numerical values stated have not been determined. The method has the capability for assessing human exposure primarily to parathion, paraoxon, methyl parathion, and EPN, but also to carbaryl, Landrin, 2-phenyIphenol, bromophos, bromophos-ethyl, iodofenphos, 2,4,5-trichlorophenol, 2,4,5-trichlorophenoxyacetic acid, fenoprop, trichloronat, and fenchlorphos. The applicability of the method was demonstrated by fortifying urine with phenolic standards corresponding to the phenolic moieties as metabolically produced from these pesticides or to the phenolic parent pesticide.