title: An improved method for retrospective quantification of sulfur mustard exposure by detection of its albumin adduct using ultra-high pressure liquid chromatography-tandem mass spectrometry.
abstract: Sulfur mustard (HD) adduct to human serum albumin (ALB) at Cys-34 residue has become an important and long-term retrospective biomarker of HD exposure. Here, a novel, sensitive, and convenient approach for retrospective quantification of HD concentration exposed to plasma was established by detection of the HD-ALB adduct using ultra-high pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) with a novel non-isotope internal standard (IS). The HD-ALB adduct was isolated from HD-exposed plasma with blue Sepharose. The adduct was digested with proteinase K to form sulfur-hydroxyethylthioethyl ([S-HETE])-Cys-Pro-Phe tripeptide biomarker. The tripeptide adduct could be directly analyzed by UHPLC-MS/MS without an additional solid phase extraction (SPE), which was considered as a critical procedure in previous methods. The easily available 2-chloroethyl ethylsulfide (2-CEES) as HD surrogate was first reported to be used as IS in place of traditional d8-HD for quantification of HD exposure. Furthermore, 2-CEES was also confirmed to be a good IS alternative for quantification of HD exposure by investigation of product ion spectra for their corresponding tripeptide adducts which exhibited identical MS/MS fragmentation behaviors. The method was found to be linear between 1.00 and 250 ng•mL(-1) HD exposure (R(2)>0.9989) with precision of <4.50% relative standard deviation (%RSD), accuracy range between 96.5% and 114%, and a calculated limit of detection (LOD) of 0.532 ng•mL(-1). The lowest reportable limit (LRL) is 1.00 ng•mL(-1), over seven times lower than that of the previous method. The entire method required only 0.1 mL of plasma sample and took under 7 h without special sample preparation equipment. It is proven to be a sensitive, simple, and rugged method, which is easily applied in international laboratories to improve the capabilities for the analysis of biomedical samples related to verification of the Chemical Weapon Convention (CWC).
authors.affiliation: Laboratory of Analytical Chemistry, Research Institute of Chemical Defence, Beijing, 102205, China.
authors.forename: ChangCai
authors.initials: C
authors.lastname: Liu
authors.forename: LongHui
authors.initials: L
authors.lastname: Liang
authors.forename: Yu
authors.initials: Y
authors.lastname: Xiang
authors.forename: HuiLan
authors.initials: H
authors.lastname: Yu
authors.forename: ShiKun
authors.initials: S
authors.lastname: Zhou
authors.forename: HaiLing
authors.initials: H
authors.lastname: Xi
authors.forename: ShiLei
authors.initials: S
authors.lastname: Liu
authors.forename: JingQuan
authors.initials: J
authors.lastname: Liu
mesh_terms: D001681:Biological Assay; D001774:Blood Chemical Analysis / Q000379:methods*; D002619:Chemical Warfare Agents; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004781:Environmental Exposure / Q000032:analysis*; D006801:Humans; D009151:Mustard Gas / Q000032:analysis*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012709:Serum Albumin / Q000032:analysis*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D002619:Chemical Warfare Agents; D012709:Serum Albumin; D009151:Mustard Gas