Simple and Rapid Screening Method for the Simultaneous Determination of Urinary VOC Metabolites Using On-line Solid-phase Extraction Coupled with Liquid Chromatography-electrospray Ionization Mass Spectrometry

• Main Authors: Chiang, Wen-Chieh, 江玟潔
• Other Authors: Lee, Hui-Ling
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/40623325310318179984

碩士 === 輔仁大學 === 化學系 === 102 === Recently, the International Agency for Research on cancer classified outdoor air pollution and particulate matter from outdoor air pollution as carcinogenic to humans (IARC Group 1), based on sufficient evidence of carcinogenicity in humans and experimental animals and strong mechanistic evidence. In particular, a wide variety of volatile organic compounds (VOCs) are volatized or released into the atmosphere and can become ubiquitous, as they originate from many different natural and anthropogenic sources, such as paints, pesticides, vehicle exhausts, cooking fumes, and tobacco smoke. Humans may be exposed to VOCs through inhalation, ingestion, or dermal contact, which may increase the risk of leukemia, birth defects, neurocognitive impairment, and cancer. Therefore, the focus of this study was the development of a simple, effective and rapid sample preparation method for the simultaneous determination of seven metabolites (6 mercaptic acids + t,t-muconic acid) derived from five VOCs (acrylamide, 1,3-butadiene, acrylonitrile, benzene, and xylene) in human urine by using automated on-line solid-phase extraction (SPE) coupled with liquid chromatography–electrospray tandem mass spectrometry (LC–MS/MS). An aliquot of each diluted urinary sample was directly injected into an autosampler through a trap column to reduce contamination, and then the retained target compounds were eluted by back-flush mode into an analytical column for separation. Negative electrospray ionization tandem mass spectrometry was utilized for quantification. The coefficients of correlation (r2) for the calibration curves were greater than 0.995. Reproducibility was assessed by the precision and accuracy of intra-day and inter-day precision, which showed that relative standard deviation (RSD) were low 0.94 to 6.57% and 3.72 to 8.94%, respectively, and recovery ranged from 90.8 to 108.9% and 92.1 to 107.7%, respectively. The limits of detection (LOD) and limits of quantification (LOQ) were determined to within 0.010 to 0.769 ng/mL and 0.033 to 2.546 ng/mL in this study. A stability study test included 3 freeze/thaw cycles during short-term storage at room temperature for 36 hours and long-term storage at -20 °C for 1 month, and the RSD (relative standard deviation) showed less than 8.44, 7.41 and 9.69%, respectively. To the best of our knowledge, this is the first study to provide simple, small injection volumes (40 µL) and a rapid LC-MS/MS method combined with an on-line SPE step for the simultaneous detection, identification, and quantification of seven metabolites derived from five VOCs in human urine for evaluation of the future risk of human exposure to volatile organic compounds. All biomarkers were measured using validated methods. Correlation analysis was performed to evaluate the relationships between these VOCs metabolites biomarkers. These biomarkers were significantly higher in smokers than nonsmokers except PMA and 2,4-DPMA. The effect of VOCs exposure on oxidative stress was examined by investigating the association between VOCs metabolites and biomarkers of DNA oxidation (8-hydroxy-2′-deoxyguanosine, 8-OHdG) and cotinine among smokers and nonsmokers. In conclusion, DHBMA, MHBMA3 and CYMA levels that are detected in a high proportion of urine samples from smokers were associated with 8-OHdG.