Objective To establish the determination method of blood N- methylcarbamoyl adduct( NMHb) in occupational workers exposed to N,N- dimethylformamide( DMF). Methods The blood samples of occupational workers exposed to DMF were collected and made into hemoglobin powder using molecular biological extraction method. After the treatment of degradation and extraction,3- methyl- 5- isopropylhydantoin( MVH),as the degradation product of N-methylcarbamoyl adduct in blood was determined by gas chromatographic- mass sp...