Prapin TharnpoophasiamPornpimol KongtipWaranya WongwitWijitr FungladdaDwip KitayapornMahidol University2018-07-242018-07-242004-09-01Southeast Asian Journal of Tropical Medicine and Public Health. Vol.35, No.3 (2004), 717-723012515622-s2.0-8444236752https://repository.li.mahidol.ac.th/handle/20.500.14594/21540The simultaneous determination of urinary trans,trans-muconic acid (t,t-MA) and S-phenylmercapturic acid (S-PMA) was performed by liquid extraction with ethyl acetate and reversed-phase high performance liquid chromatography (RP-HPLC) on a Hypersil-ODS column using the gradient mobile phase of methanol and 0.0012 N perchloric acid and diode array detection at 205 and 264 nm for S-PMA and t,t-MA, respectively. The retention times for t,t-MA and S-PMA were 3.8 and 12.3 minutes, respectively. The recoveries of t,t-MA and S-PMA were > 97%; between-day precisions were all within 8% RSD (100x SD/mean). The method was applied to analyze the urinary t,t-MA and S-PMA of 59 service station attendants exposed to average benzene concentrations in the air of 0.20±0.18 ppm. Significant differences in pre-shift and post-shift urinary t,t-MA between smokers and non-smokers were found.Mahidol UniversityMedicineArticleSCOPUS