In vitro adduct formation of phosgene with albumin and hemoglobin in humanblood

The development of procedures for retrospective detection and quantitation of exposure to phosgene, based on adducts to hemoglobin and albumin, is des cribed. Upon incubation of human blood with [C-14]phosgene (0-750 mu M), a significant part of radioactivity (0-13%) became associated with globin and albumin. Upon Pronase digestion of globin, one of the adducts was identifi ed as the pentapeptide O=C-(V-L)-S-P-A, representing amino acid residues 1- 5 of cl-globin, with a hydantoin function between N-terminal valine and leu cine. Micro-LC/tandem MS analyses of tryptic as well as V8 protease digests identified one of the adducts to albumin as a urea resulting from intramol ecular bridging of lysine residues 195 and 199. The adducted tryptic fragme nt could be sensitively analyzed by means of micro-LC/tandem MS with multip le-reaction monitoring (MRM), enabling the detection in human blood of an i n vitro exposure level of greater than or equal to 1 mu M phosgene.