Pyrethrum and pyrethroid metabolites (after liquid phase extraction) in urine [Biomonitoring Methods, 2013]

The present method is used to determine trans-chrysanthemum dicarboxylic acid (trans-CDCA) as metabolite of the pyrethroids allethrin, phenothrin, resmethrin, tetramethrin and of pyrethrum as well as cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-cyclopropane carboxylic acid (cis- and trans-DCCA), cis-3-(2,2-dibromovinyl)-2,2-dimethyl-cyclopropane carboxylic acid (cis-DBCA), 4-fluoro-3-phenoxybenzoic acid (FPBA) and 3-phenoxybenzoic acid (3-PBA) as metabolites of the pyrethroids permethrin, cyfluthrin, cypermethrin and deltamethrin. Additionally, the presented method enables the determination of cis-chrysanthemum dicarboxylic acid (cis-CDCA). With the gas chromatographic/mass spectrometric method presented here, the urinary concentration of seven pyrethroid and pyrethrum metabolites can be determined sensitively and reliably in one analytical procedure. Due to its sensitivity the procedure is suitable for detecting exposures relevant to both environmental medicine and occupational medicine. The method comprises alkaline cleavage of the conjugates, the extraction of the carboxylic acids using solid phase extraction, as well as derivatisation by esterisation with hexafluoroisopropanol and diisopropyl carbodiimide. The analytical determination is carried out by gas chromatography/mass spectrometry after negative chemical ionisation. Quantitation is performed by use of two internal standards.