Determination of 2,5-hexanedione and N-methylformamide in urine by gas chromatography

Methods for the clinical testing of 2,5-hexanedione and N-methylformamide, urinary metabolites of n-hexane and N,N-dimethylformamide, respectively, were established by capillary column GLC. Recovery rates of 2,5-hexanedione and N-methylformamide from urine were 80.2-108.9% and 99.6-104.2%, respectively. Coefficients of variation (C.V.) for the amount of each product added were 3.1%, 1.8% (intra-assay) and 5.7%, 3.3% (inter-assay), respectively. The concentration ranges of metabolites from urine of healthy subjects without exposure to these organic solvents were less than or equal to 0.5 mg/l (2,5-hexanedione), less than or equal to 1.5 mg/l (N-methylformamide), respectively.