SENSITIVE AND SELECTIVE DETERMINATION OF METABOLICALLY FORMED TRANS-DIHYDRODIOLS AND PHENOLS OF BENZO[A]PYRENE IN WATER AND URINE SAMPLES BY HPLC WITH AMPEROMETRIC DETECTION

A method has been developed to separate hydroxylated metabolites of th e carcinogenic polycyclic aromatic hydrocarbon benzo[a]pyrene, i. e. t rans-4,5-, 7,8-, 9,10-dihydrodiol and 1-, 3-, 7-, and 9-phenol, by HPL C with amperometric detection employing an isocratic methanol/water el uent (70:30, v/v) containing 0.5 g/L sulfuric acid and 1 g/L lithium p erchlorate. Compared with the usually applied fluorescence (lambda(ex) = 265 nm, lambda(em) = 460 nm) and ultraviolet (lambda = 265 nm) dete ction, the amperometric technique is about 2-12 times more sensitive f or the determination of all metabolites investigated. The method was a pplied to the determination of the seven metabolites of benzo[a]pyrene in different water samples and in urine after solid-phase extraction (SPE). The results obtained by HPLC with amperometric detection after SPE enrichment from an aqueous extract of a soil sample and from the u rine of a rat intragastrically treated with benzo[a]pyrene agreed well with the values determined with fluorescence and/or UV detection.