title: An online automatic sample cleanup system for the quantitative detection of the benzene exposure biomarker S-phenylmercapturic acid in human urine by electrospray ionization tandem mass spectrometry.
abstract: An online automatic sample cleanup system was developed for use with electrospray ionization tandem mass spectrometry (ESI-MS-MS) for the quantitative detection of the benzene exposure biomarker S-phenylmercapturic acid (S-PMA) in human urine. The sample clean-up system was constructed with an autosampling device, a reversed-phase C18 trap cartridge, a two-position switching valve, and controlling computer software and hardware. The sample cleanup system was interfaced directly with the ESI source of a triple-stage-quadrupole MS using multiple reaction monitoring of negative product ions derived from S-PMA and the internal standard as the detection mode. The calibration curve was linear using human urine spiked at concentrations from 0.23 to 100 mg/L S-PMA (R2 = 0.997). The detection limit of the analytical system for neat S-PMA standard solution was 0.04 microg/L, whereas the detection limit was estimated to be lower than 0.35 microg/L for a urine matrix containing trace amounts of S-PMA. Without tedious manual sample cleanup procedures, the analytical system is fully automatic and therefore useful for high-throughput urinary S-PMA determination. With the selectivity and the sensitivity provided by MS-MS detection, the analytical system can be used for high-throughput and accurate determination of S-PMA levels in human urinary samples as a biomarker for benzene exposure.
authors.affiliation: Department of Environmental and Occupational Health, National Cheng Kung University College of Medicine, Tainan, Taiwan. liaopc@mail.ncku.edu.tw
authors.forename: Pao-Chi
authors.initials: PC
authors.lastname: Liao
authors.forename: Chien-Ming
authors.initials: CM
authors.lastname: Li
authors.forename: Lung-Cheng
authors.initials: LC
authors.lastname: Lin
authors.forename: Chien-Wen
authors.initials: CW
authors.lastname: Hung
authors.forename: Tung-Sheng
authors.initials: TS
authors.lastname: Shih
mesh_terms: D000111:Acetylcysteine / Q000031:analogs & derivatives* / Q000652:urine*; D000395:Air Pollutants, Occupational / Q000032:analysis; D001331:Automation; D001554:Benzene / Q000032:analysis*; D015415:Biomarkers / Q000652:urine; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D019570:Inhalation Exposure; D016273:Occupational Exposure; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000295:instrumentation* / Q000379:methods; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation* / Q000379:methods
chemical_list: D000395:Air Pollutants, Occupational; D015415:Biomarkers; C053003:S-phenyl-N-acetylcysteine; D001554:Benzene; D000111:Acetylcysteine