In Vitro Adduct Formation of Phosgene with Albumin and Hemoglobin in Human Blood

• Published in: Chemical research in toxicology 2000-08, Vol.13 (8), p.719-726
• Main Authors: Noort, Daan, Hulst, Albert G, Fidder, Alex, van Gurp, Ronald A, de Jong, Leo P. A, Benschop, Hendrik P
• Format: Article
• Language: English
• Subjects: Albumins - metabolism; Chromatography, High Pressure Liquid; Environmental Exposure; Environmental Monitoring - methods; Hemoglobins - metabolism; Humans; Mass Spectrometry; phosgene; Phosgene - metabolism; Phosgene - pharmacology; Protein Binding - drug effects
• ISSN: 0893-228X; 1520-5010
• DOI: 10.1021/tx000022z

The development of procedures for retrospective detection and quantitation of exposure to phosgene, based on adducts to hemoglobin and albumin, is described. Upon incubation of human blood with [14C]phosgene (0−750 μM), a significant part of radioactivity (0−13%) became associated with globin and albumin. Upon Pronase digestion of globin, one of the adducts was identified as the pentapeptide OC-(V-L)-S-P-A, representing amino acid residues 1−5 of α-globin, with a hydantoin function between N-terminal valine and leucine. 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 intramolecular bridging of lysine residues 195 and 199. The adducted tryptic fragment could be sensitively analyzed by means of micro-LC/tandem MS with multiple-reaction monitoring (MRM), enabling the detection in human blood of an in vitro exposure level of ≥1 μM phosgene.