Quantification of N-(3-chloro-2-hydroxypropyl)valine in human haemoglobin as a biomarker of epichlorohydrin exposure by gas chromatography-tandem mass spectrometry with stable-isotope dilution.
Epichlorohydrin (ECH) is an important industrial intermediate for the production of polymers and surface coatings. Animal experiments support the classification of ECH as a carcinogen, and a significant contribution to the cancer risk of ECH exposed humans has to be considered. Upon uptake, epichlorohydrin reacts with nucleophilic moieties of N- and S-containing macromolecules to form stable adducts, e.g. with haemoglobin. In this article, we describe a GC-tandem MS method for the quantitative analysis of the primary ECH adduct to the N-terminal amino acid of human haemoglobin, i.e. of N-(3-chloro-2-hydroxypropyl)valine (CHPV), using a globin labelled with d(5)-ECH as the internal standard. Incubation of erythrocyte lysate from human blood with ECH or d(5)-ECH yielded two reaction products, with CHPV being the major component. The GC-tandem MS method is based on a modified Edman degradation procedure with subsequent O-acetylation. The limits of detection and quantification of this method are 10 and 25 pmol/g globin, respectively. Intra- and inter-assay imprecision of the method was about 12 and 15%, respectively, and the mean recovery was 105 and 96% at the levels of 25 and 100 pmol of CHPV per g globin, respectively. The present study reports for the first time on the analysis of CHPV as a haemoglobin adduct of ECH using GC-tandem MS and a stable-isotope labelled internal standard. By this method we quantified haemoglobin adducts of ECH in the blood of subjects potentially exposed to ECH after a freight train accident. Our study points to CHPV in human haemoglobin as a possible biomarker for epichlorohydrin exposure.
Bader
Michael
M
Institute for Occupational Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany. bader.michael@mh-hannover.de
Rosenberger
Wolfgang
W
Gutzki
Frank-Mathias
FM
Tsikas
Dimitrios
D
D000107:Acetylation; D015415:Biomarkers / Q000737:chemistry*; D002138:Calibration; D004811:Epichlorohydrin / Q000633:toxicity*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006454:Hemoglobins / Q000737:chemistry*; D006801:Humans; D007554:Isotopes; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods*
D015415:Biomarkers; D006454:Hemoglobins; D007554:Isotopes; D004811:Epichlorohydrin