Determination of Urinary Trans, Trans-Muconic Acid by Gas Chromatography in Gasoline Service Attendants

Abstract

This study aims to develop the reliable method for analysis of urinary trans, trans-muconic acid (t,t-ma) using methanol in acid medium (HCl) as derivatization reagent, a low cost and less toxic reagent and analysis by GC/FID. The urinary t,t-ma and benzoic acid internal standard was extracted, derivatized into dimethyl cis trans, trans-muconate and methyl benzoate, and analysis with GC. The method was applied to analysis of urinary t,t-ma of 54 gasoline service station attendants. Personal air samples were also collected. Results showed accuracies of urinary t,t-ma (1.5-37.5 μg/ml) ranging from 98.0 to 99.6% with less than 2.5% relative standard deviation (RSD). The detection limit of t,t-ma in urine was 0.75 μg/ml urine. The average benzene concentration at breathing zone of the gasoline service station attendants was 0.19 ± 0.16 ppm, ranging from non-detectable to 0.65 ppm. The average urinary trans, trans-muconic acid was 458.4 ± 446.4 ranging from non-detectable to 2274 μg/g creatinine.