High-performance liquid chromatographic determination of n-methylformamide, a biological index for occupational exposure to dimethylformamide

This report describes an analytical method for the biological monitoring of workers exposed to N,N-dimethylformamide (DMF), a solvent widely used in t he chemical industry. The human main metabolites of DMF are N-hydroxymethyl -N-methylformamide (HMMF) and the minor metabolites N-methylformamide (NMF) and N-acetyl-S-(N-methylcarbamoyl)cysteine. The metabolite selected by the American Conference of Governmental Hygienists for occupational biomonitor ing purposes, is NMF measured by gas chromatographic analysis, as during it HMMF may be converted to the minor metabolite NMF. HMMF and NFM can be mea sured independently using HPLC analysis. The procedure proposed here involv es the thermal transformation of the primary metabolite HMMF into the minor metabolite NMF, which is then determined by HPLC. This method makes it pos sible to determine, using HPLC, both metabolites of DMF by measuring only o ne peak, thus offering two major advantages: (i) it increases the sensitivi ty of the test and (ii) it deploys only one reference standard. (C) 1999 El sevier Science B.V. All rights reserved.