On-line chiral analysis of benzylmercapturic acid and phenylmercapturic acid in human urine using UPLC-QToF mass spectrometry with the kinetic method

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• 作者：Hua Jin^a ; T. Daniel Thangadurai^a ; Sung-Chan Jo^b ; Dongri Jin^c ; Shengyun Cui^c ; Yong-Ill Lee^a ; ^{yilee@changwon.ac.kr}
• 关键词：Chiral analysis ; d/l-Phenylmercapturic acid ; d/l-Benzylmercapturic acid ; Enantiomeric excess ; Kinetic method
• 刊名：Microchemical Journal
• 出版年：2012
• 期刊代码：64_0026265x
• 类别：ce
• 出版时间：July, 2012
• 卷：103
• 期：Complete
• 页码：170-176
• 文件大小：818 K

摘要

A novel analytical method was developed for chiral analysis utilizing on-line ultra-performance liquid chromatography (UPLC) coupled with a quadrupole time-of-flight mass spectrometry (QToF-MS). This developed method was applied to discriminate and quantify accurately the chiral biomarkers, d/l-phenylmercapturic acid (PMA) and d/l-benzylmercapturic acid (BMA), in urine samples. Initially, UPLC was used to separate achirally the mixture of two biomarkers and then sequential on-line mass spectrometry differentiated successfully the enantiomers of each biomarker. After separating the two molecular species, a mixture of metal ion and reference ligand was added to the eluent of UPLC to produce trimeric M(II)-bound complex ion, [M^II(A)(ref*)₂-H]⁺ (M^II, divalent transition metal ion; A, analyte; ref*, reference ligand). The collision-induced dissociation (CID) of the trimeric complex ion resulted in two dimeric complex ions, [M^II(A)(ref*)-H]⁺ and [M^II(ref*)₂-H]⁺. The ratio of the abundances for the two product ions, the branching ratio, was established for one enantiomer relative to the other, which affects chiral discrimination. The compounds, Cu(II) as a central metal ion and L-Pro as a reference ligand were selected for the optimum distinction of chiral PMA and BMA. Rapid quantitative chiral analysis of PMA and BMA was achieved by constructing calibration curves derived from the kinetic method, related to the ratio of the branching ratios against the enantiomeric composition of their mixture.