Survey of albumin purification methods for the analysis of albumin-organic toxicant adducts by liquid chromatography-electrospray ionization-tandem mass spectrometry

HSA has been shown to react with many organic toxicants to form adducts that are useful biomarkers for exposure. Albumin isolation is an important first step for the analysis of these protein-toxicant adducts. We tested several approaches to isolate albumin from serum treated with an electrophilic organic toxicant known to form adducts with albumin, i.e., sulfur mustard agent (HD) (2,2'-dichloroethyl sulfide), in order to evaluate these techniques as purification methods. To select the most efficient isolation strategy, methods were evaluated using gel electrophoresis, total protein quantitation, and peptide-adduct identification by MS. Results suggest that the albumin-rich fractions obtained can be used to identify exposure by quantitating the albumin adducts to electrophilic organic toxicants such as HD. The HiTrap Blue HP albumin isolation system appears to display the most promising results for purifying albumin to detect HD-adducts, exhibiting high purification efficiency, satisfactory albumin recovery, promising specificity, and a higher loading capacity for serum.