S-Phenyl-N-Acetylcysteine in Urine of Rats and Workers After Exposure to Benzene

Abstract

An HPLC method for the determination of S-phenyl-N-acetylcysteine in urine is described. The sensitivity is 6 mumol/L (CV = 9%) urine. Exposure of rats to six different concentrations of benzene, ranging from 0-30 ppm, was highly associated with urinary excretion of S-phenyl-N-acetylcysteine (r = 0.86) and with total phenol (r = 0.81). A background level of phenol was found in urine of both non-exposed rats and of non-exposed referents. However, no background excretion of S-phenyl-N-acetylcysteine was found, either in rats or in humans. In urine of exposed rats, the level of S-phenyl-N-acetylcysteine was approximately five times lower than the phenol level. Workers occupationally exposed to benzene, showing high levels of urinary phenol, revealed low concentrations of urinary S-phenyl-N-acetylcysteine. The biological monitoring of industrial exposure to benzene by determination of S-phenyl-N-acetylcysteine in urine is not better than the determination of phenol in urine.

Validation of an HPLC–MS/MS method for the simultaneous determination of phenylmercapturic acid, benzylmercapturic acid and o-methylbenzyl mercapturic acid in urine as biomarkers of exposure to benzene, toluene and xylenes

“…Nevertheless, exposure to high concentrations of these compounds can induce changes in the central nervous system and other neurotoxic effects [3][4][5]. The metabolism of these aromatic compounds has been thoroughly investigated [6][7][8]. At least 90% of the absorbed BTX is excreted through the kidneys as metabolites, including trans,trans-muconic acid and phenol for benzene, hippuric acid and o-cresol for toluene and methylhippuric acids for xylenes.…”

Avaliação dos métodos analíticos para a determinação de metabólitos do benzeno como potenciais biomarcadores de exposição humana ao benzeno no ar

“…A maioria dos métodos oferecem limites de detecção iguais ou inferiores a 1 µg.dm -3 , valores que permitem diferenciar populações de fumantes e não fumantes não expostas ocupacionalmente. As metodologias que não utilizam o procedimento de derivatização 89,91 apresentam valores altos de limites de detecção, o que inviabiliza a utilização deste metabólito como IBE ao benzeno. Na determinação de um IBE, a sensibilidade e a simplicidade do procedimento analítico devem ser consideradas para selecionar o método analítico adequado.…”

Application of the standard addition approach for the quantification of urinary benzene

“…Among the exposure biomarkers, two benzene metabolites have been currently adopted by ACGIH: the S-phenylmercapturic acid (S-PMA) and the trans,transmuconic acid. The first one, representing about 1% of the absorbed dose of benzene [14], is a specific metabolite, and it is considered a useful biomarker also for the measurement of low levels of benzene exposure; nevertheless it needs high levels of sensitivity, requiring sophisticated instrumentation and expertise. The second one derives not only from the metabolism of benzene but also from the sorbic acid (a widely used food preservative), hence the presence of trans,transmuconic acid in urine is not depending exclusively on exposure to benzene.…”