Identification and Quantification of 1-Hydroxybutene-2-yl Mercapturic Acid in Human Urine by UPLCHILIC-MS/MS as a Novel Biomarker for 1,3-Butadiene Exposure
1,3-Butadiene (BD) is a Class 1 carcinogen present in polluted air of workplaces, in automobile exhaust, and in tobacco smoke. 2-Hydroxybutene-1-yl mercapturic acid (2-MHBMA) is a urinary metabolite often measured as a biomarker for exposure to BD. During this study, the authors demonstrated for the first that an additional MHBMA isomer is present at significant amounts in human urine, 1-hydroxybutene-2-yl mercapturic acid (1-MHBMA). For its quantification, a highly sensitive UPLC-HILIC-MS/MS method was developed and validated. Analysing urinary samples of 183 volunteers, the authors demonstrate that 1-MHBMA is a novel and potentially more reliable biomarker for BD exposure than the commonly analysed 2-MHBMA.