Measurement of urinary N-acetyl-S-(N-methylcarbamoyl)cysteine by high-performance liquid chromatography with direct ultraviolet detection.
A new high-performance liquid chromatographic (HPLC) method is described for the determination of urinary N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC), the final product of the conjugation reaction between a metabolic intermediate of N,N-dimethylformamide (DMF) and glutathione. Urine samples were purified by C(18) solid-phase extraction and then directly analysed by HPLC with an Aminex Ion Exclusion HPX-87H column maintained at 25 degrees C and a UV detector set at 196 nm. Under isocratic conditions (2.4 mM sulphuric acid, flow-rate=0.6 ml/min) AMCC eluted at 20.2 min. The reproducibility (C.V.%) was 1.3-2.7% (intra- and inter-assay, N = 5); the accuracy was 98.0+/-1.7% at 10 mg/l and 101.9+/-1.5% at 800 mg/l (mean+/-SD, N = 3). AMCC was measured in urine from 22 exposed subjects. A strong correlation was found between AMCC and environmental DMF [AMCC (mg/g creatinine)=3.40xDMF (mg/m(3)) + 3.07; r=0.95], while in the urine of 20 unexposed subjects the concentration of AMCC was constantly below the detection limit of the method (0.9 mg/l in urine). The method described appears to be useful for the biological monitoring of DMF exposure.
Imbriani
Marcello
M
Dipartimento di Medicina Preventiva, Occupazionale e di Comunita': II Sezione di Medicina del Lavoro, Pavia, Italy.
Negri
Sara
S
Ghittori
Sergio
S
Maestri
Luciano
L
D000111:Acetylcysteine / Q000031:analogs & derivatives* / Q000652:urine*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*
C052469:N-acetyl-S-(N-methylcarbamoyl)cysteine; D000111:Acetylcysteine