- P-ISSN 1225-0163
- E-ISSN 2288-8985
The author assessed the availability of urine reference material for proficiency test provided forlaboratories in occupational health. N-methylacetamide is the biomarker of exposure to N,N-dimethyl acetamide,which was used as the substitute for hepatotoxic N,N-dimethylformamide (DMF). N-methylacetamide (NMAC)urine samples of 3 different levels covering the 0.2~2 times of the exposure limit were tested. Stability testup to 180 days (0, 7, 30, 60, 180 days) at 4 different temperatures (-60, -20, 5, 25 oC) and homogeneity testwere performed for these samples. New analytical condition by GC/MSD using SIM mode (m/z 58, 59) andDB-624 column was investigated for better selectivity, sensitivity and resolution. Urinary NMAC samplesshowed good homogeneity for 3 levels. These samples also showed good stability up to 180 days. The dataof stability and homogeneity of urinary DMAC confirmed the basis of including this item into Korean proficiencytest for occupational health laboratories since 2008.