[Study of N-methylcarbamoylated hemoglobin in blood of being an exposure biomarker of N, N-dimethylformamide].

Objective To assess the value of blood N-methylcarbamoylated haemoglobin (NMHb) as a biomarker of N,N-dimethylformamide (DMF) exposure.Methods Seventy-two DMF processing workers in a synthetic leather factory were included in the DMF exposure group,and 12 workers in a food factory without exposure to DMF were included in the control group.Long-time individual sampling in workplace was performed among 45 workers in the exposure group,accompanied by a questionnaire survey.Blood and urine were collected for the determination of urinary N-methylformamide (NMF),urinary creatinine,and blood NMHb.Air DMF and urinary NMF were determined by gas chromatography.NMHb in blood was degraded to 3-methyl-5-isopropylhydantoin by Edman degradation before it could be determined by gas chromatography/mass spectrometry.Results Air DMF in workplace and NMF in post-shift urine were both correlated with NMHb in blood,and the respective regression equations were LgN MHb (nmol/g globin) =0.32×LgDMF (mg/m3) + 1.8 (r=0.60,P＜0.005),and LgNMHb (nmol/g globin)=0.47×LgNMF (mg/g Cr) + 1.4 (r=0.56,P＜0.005).Conclusion NMHb can be used as a biomarker of long-term exposure to DMF. Key words: N, N-dimethylformamide(DMF);  biomarker, N-methylcarbamoylat-ed haemoglobin(NMHb); N-methylformamide(NMF)