Urinary Hippuric Acid Excretion as an Index of Toluene Exposure

Abstract

Abstract A simple procedure is described for the analysis of hippuric acid in urine. The sample is extracted with an isopropyl alcohol-diethyl ether mixture, and the hippuric acid is measured in the extractant by ultraviolet spectrophotometry. The excretion of hippuric acid in urine as a metabolic product of toluene was studied in relation to its usefulness in industrial exposures to toluene. Good correlation of hippuric acid content of end-of-shift samples and toluene exposure was found in studies performed in leather-finishing and rubber-coating plants. The hippuric acid test was also found to be useful in measuring the adequacy of cartridge-type respirators in tank painting work.