title: Development of liquid chromatography-electrospray ionization-tandem mass spectrometry methods for determination of urinary metabolites of benzene in humans.
abstract: To investigate the ways in which different levels of exposure affect the metabolic activation pathways of benzene in humans, and to examine the relationship between urinary metabolites and other biological markers, we have developed two sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays for quantitation of the benzene metabolites trans,transmuconic acid (t,t-MA), S-phenylmercapturic acid (S-PMA), hydroquinone (HQ), catechol (CAT), and for estimation of 1,2,4-trihydroxybenzene (BT). In our first assay, urinary S-PMA and t,t-MA were measured simultaneously by liquid chromatography-electrospray ionization-tandem mass spectrometry-selected reaction monitoring (LC-ESI-MS/MS-SRM) in the negative ionization mode. In this assay, the metabolites [13C6]-S-PMA and [13C6]-t,t-MA were used as internal standards. The efficacy of this specific assay was evaluated in human urine specimens from 28 smokers and 18 nonsmokers serving as the benzene-exposed and nonexposed groups, respectively. The coefficient of variation (CV) of analyses on different days (n = 8) for S-PMA was 7% for samples containing 9.4 micrograms/L urine, and for t,t-MA was 10% for samples containing 0.07 mg/L. The mean levels of S-PMA and t,t-MA in smokers were 1.9-fold (p = 0.02) and 2.1-fold (p = 0.03) higher, respectively, than those in nonsmokers.
authors.affiliation: American Health Foundation, Valhalla, NY 10595, USA.
authors.forename: A A
authors.initials: AA
authors.lastname: Melikian
authors.forename: M
authors.initials: M
authors.lastname: Meng
authors.forename: R
authors.initials: R
authors.lastname: O'Connor
authors.forename: P
authors.initials: P
authors.lastname: Hu
authors.forename: S M
authors.initials: SM
authors.lastname: Thompson
mesh_terms: D000111:Acetylcysteine / Q000031:analogs & derivatives / Q000652:urine; D001554:Benzene / Q000032:analysis* / Q000493:pharmacokinetics; D015415:Biomarkers / Q000652:urine; D001711:Biotransformation; D002273:Carcinogens / Q000032:analysis* / Q000493:pharmacokinetics; D002396:Catechols / Q000652:urine; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D006873:Hydroquinones / Q000652:urine; D013058:Mass Spectrometry / Q000379:methods*; D012680:Sensitivity and Specificity; D012907:Smoking / Q000652:urine; D013011:Sorbic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D016482:Urinalysis / Q000379:methods*
chemical_list: D015415:Biomarkers; D002273:Carcinogens; D002396:Catechols; D006873:Hydroquinones; C005939:muconic acid; C053003:S-phenyl-N-acetylcysteine; D001554:Benzene; D000111:Acetylcysteine; D013011:Sorbic Acid