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

Abstract

To assess the value of blood N-methylcarbamoylated haemoglobin (NMHb) as a biomarker of N, N-dimethylformamide (DMF) exposure. 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. Air DMF in workplace and NMF in post-shift urine were both correlated with NMHb in blood, and the respective regression equations were LgNMHb (nmol/g globin) = 0.32×LgDMF (mg/m(3))+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). NMHb can be used as a biomarker of long-term exposure to DMF.