Simultaneous analysis of hemoglobin adducts of acrylamide and glycidamide by gas chromatography-mass spectrometry

Acrylamide (AA) is a carcinogen in experimental animals. Glycidamide (GA), formed by metabolic epoxidation of AA, is believed to be responsible for th e carcinogenicity of AA. Occupational exposure to AA has been assessed earl ier by measurement of its adducts with N-terminal valine in hemoglobin. A b ackground of AA adducts [N-(2-carbamoylethyl) valine (AAVal), about 30 pmol /g globin] was found in individuals without known exposure to the compound. The method previously available for adducts of GA only allowed analysis of samples from highly exposed individuals and showed similar levels of AAVal and adducts of GA [N-(2-hydroxy-2-carbamoylethyl)valine (GAVal)]. We have developed a sensitive method for simultaneous quantification of adducts of GA and AA, which is suitable down to low exposure levels. The method is bas ed on the so-called modified Edman method, where globin is reacted with pen tafluorophenyl isothiocyanate under neutral conditions, The valine adducts are then extracted in the form of pentafluorophenylthiohydantoin (PFPTH) de rivatives, The analytical procedure included reaction of the PFPTH derivati ves with acetic anhydride in order to protect the hydroxyl group of GAVal, The PFPTH derivatives of AAVal and GAVal were analyzed by gas chromatograph y/tandem mass spectrometry, (H-2(2))AAVal-PFPTH was used as the internal st andard. The method was applied to samples from 11 workers at an AA producti on plant, 1 nonexposed nonsmoker, and a few participants of a smoking cessa tion program. AAVal levels were in the range 27-1854 pmol/g globin, Recorde d levels of GAVal were 3-12% of those of AAVal, suggesting that previous me asurements of GAVal overestimate GAVal at low levels Of exposure to AA. (C) 1999 Academic Press.