title: Quantitative colorimetric determination of urinary p-aminophenol with an automated analyzer.
abstract: We developed an automated colorimetric method for the quantitative determination of p-aminophenol with a Cobas Mira analyzer. The procedure can be used for the biological monitoring of human exposure to aniline. An absorbed aniline dose is extensively oxidized to p-aminophenol, which is excreted in urine mainly as glucurono- and sulfo- conjugates. After enzymatic hydrolysis, we reacted the free compound with resorcinol in the presence of manganese ions to form an indophenol dye, which is measured at 550 nm. Excellent accuracy (102.8%, 103.9%, and 96.8% at 2.5, 50, and 90 mg/L, respectively) and precision (7.7%, 2.1%, and 0.8% CV for within-run and 11.1%, 4.7%, and 4.6% for total reproducibility at 2.5, 50, and 90 mg/L, respectively) were achieved over a linear concentration range of 2.0 to 100 mg/L. The detection limit was 0.9 mg/L and no significant interference (except for o-aminophenol) was found for several investigated drugs and related compounds. The proposed method was used for a stability study and to analyze several samples from an occupational health screen.
authors.affiliation: Laboratorium voor Toxicologie, Universiteit Gent, Belgium.
authors.forename: J F
authors.initials: JF
authors.lastname: Van Bocxlaer
authors.forename: K M
authors.initials: KM
authors.lastname: Clauwaert
authors.forename: W E
authors.initials: WE
authors.lastname: Lambert
authors.forename: A P
authors.initials: AP
authors.lastname: De Leenheer
mesh_terms: D000328:Adult; D000627:Aminophenols / Q000652:urine*; D000814:Aniline Compounds; D001322:Autoanalysis; D002712:Chlorides; D003124:Colorimetry / Q000379:methods*; D006801:Humans; D007202:Indicators and Reagents; D007215:Indophenol; D017895:Manganese Compounds; D016273:Occupational Exposure; D015203:Reproducibility of Results; D012118:Resorcinols; D012680:Sensitivity and Specificity
chemical_list: D000627:Aminophenols; D000814:Aniline Compounds; D002712:Chlorides; D007202:Indicators and Reagents; D017895:Manganese Compounds; D012118:Resorcinols; D007215:Indophenol; C025340:manganese chloride; C026729:4-aminophenol; C023650:aniline; C031389:resorcinol