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Epidemiological evidence that occupational exposure to o-toluidine and aniline is associated with an increased risk of bladder cancer led to efforts to identify biomarkers of workplace exposures to these aromatic amines. For the determination of o-toluidine and aniline in worker urine specimens, a method using high performance liquid chromatography (HPLC) followed by electrochemical detection was developed. The limits of detection were 0.6 microgram/l and 1.4 micrograms/l for o-toluidine and aniline, respectively. Recovery of o-toluidine and aniline from spiked urine averaged 86% and 93%, respectively, over a range of 4-100 micrograms/l. Reproducibility in the range 2-100 micrograms/l for analyses of split field samples was 13% (average RSD) for o-toluidine and 16% (average RSD) for aniline. Application of this method to pre- and post-shift samples collected from potentially exposed and unexposed workers indicated elevated concentrations of o-toluidine and aniline in urine from exposed workers. To develop methods for biomarkers of internal dose, o-toluidine binding to the blood proteins hemoglobin and albumin was investigated utilizing in-vivo (rodent) and in-vitro (hemoglobin and albumin) studies. Base-hydrolyzable protein adducts were analyzed by HPLC (fluorescence) and/or GC/electron capture (EC). The methods were compared for sample preparation requirements, selectivity and sensitivity. While the GC/EC method was more sensitive than HPLC, the presence of interfering peaks limited the utility of this approach. Results from these studies suggested that the HPLC method could be useful for determination of o-toluidine exposures in individuals acutely or chronically exposed to high levels.

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. . The National Institute of Environmental Health Sciences (NIEHS) and Brogan & Partners are collaborating with JSTOR to digitize, preserve and extend access to Environmental Health Perspectives. The routes of 14C excretion following the administration of a single oral 230 mg/kg body weight dose of 2-ethoxyethanol [ethanol-l,2-14C] or 2-ethoxyethanol [ethoxy-l-14C] to male Sprague-Dawley rats were investigated. Elimination of the 14C by the urinary route accounted for 76 to 80% of the dose within 96 hr.The main pathway of biotransformation is oxidation to the corresponding acid, with some subsequent conjugation of the acid metabolite with glycine. The major metabolites, ethoxyacetic acid and iV-ethoxyacetyl glycine, representing 73 to 76% of the administered dose, were eliminated in the urine. The major difference in the metabolic profiles of the two radiochemicals was in the rate and amount of 14C02 expired via the lung. Of the administered 14C, 11.7% of the ethoxy-labeled and 4.6% of the ethanol-labeled compounds were eliminated as C02. The biological half-time was 9.9 ? 1.5 hr for the ethoxy-labeled compound and 12.5 ? 1.9 hr for the ethanol label. After administration of the ethanol-labeled compound, the only radiolabeled component found in the rat testes was identified as ethoxyacetic acid. Results of this study suggest that the reported testicular effects in the rat may be a result of tissue levels of ethoxyacetic acid.

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