title: Capillary electrophoresis determination of urinary muconic acid as a biological marker for benzene in cigarette smoke.
abstract: trans,trans-Muconic acid (MA), a benzene metabolite in urine, has currently been indicated as a biological marker for benzene in cigarette smoke. The available methodologies for MA present a few shortcomings, such as lack of specificity and labor-intensive sample pretreatment. In this work, a capillary electrophoresis method for separation, identification, and quantification of urinary muconic acid has been implemented. The electrolyte consisted of a 60-mM phosphate buffer solution (pH 7), containing 0.1 mM cetyltrimethylammonium bromide (CTAB) as an electroosmotic flow modifier. Urine samples from nonsmokers and smokers were filtered through a 0.22-micron membrane prior to injection in a 75 microns i.d. x 80 cm capillary. The analysis was conducted under constant voltage conditions of -30 kV and direct UV detection at 262 nm. The detection capability of the electrophoresis system was enhanced by employing a high-sensitivity optical cell, positioned at 60 cm from the injection port. The CE methodology presented an overall analysis time of less than 10 min, with 5 min spent for capillary conditioning and approximately 5 min for run completion. The method was found to be sensitive for the determination of MA down to 25 micrograms/L, with a percentage recovery of 100 +/- 8%, and suitable for discriminating urinary MA from nonsmokers and smokers.
authors.affiliation: Instituto de Química, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: M X
authors.initials: MX
authors.lastname: Coutrim
authors.forename: A V
authors.initials: AV
authors.lastname: Jager
authors.forename: L R
authors.initials: LR
authors.lastname: de Carvalho
authors.forename: M F
authors.initials: MF
authors.lastname: Tavares
mesh_terms: D001554:Benzene / Q000032:analysis*; D015415:Biomarkers / Q000652:urine*; D002138:Calibration; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods; D006801:Humans; D007202:Indicators and Reagents; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012906:Smoke; D012907:Smoking / Q000652:urine*; D013011:Sorbic Acid / Q000031:analogs & derivatives* / Q000032:analysis
chemical_list: D015415:Biomarkers; D007202:Indicators and Reagents; D012906:Smoke; C005939:muconic acid; D001554:Benzene; D013011:Sorbic Acid