Simultaneous HPLC determination of urinary metabolites of toluene, xylenes, and ethylbenzene; and its application to biological monitoring of Tunisian workers exposure

A simple, sensitive, and reproducible high performance liquid chromatographic procedure is described for the simultaneous determination of urinary metabolites of several aromatic hydrocarbons: mandelic and phenylglyoxylic acids from ethylbenzene; hippuric acid from toluene, and methylhippuric acids from xylenes. The employed mobile phase and the chromatographic conditions allowed relatively low detection limits (0.1 to 0.2 mg/L). The method was tested on 33 workers in the paint industry and on 33 nonoccupationally exposed Tunisian subjects. A significant difference of metabolite concentrations was found between the two groups. In the exposed group, most of the measured levels were lower than the biological exposure indices.