Sheng Huaming, Williams Peggy E, Tang Weijuan, Zhang Minli, Kenttämaa Hilkka I
Purdue University, Department of Chemistry, West Lafayette, IN 47907, USA.
Analyst. 2014 Sep 7;139(17):4296-302. doi: 10.1039/c4an00677a.
A mass spectrometric method utilizing gas-phase ion/molecule reactions of 2-methoxypropene (MOP) has been developed for the identification of the sulfoxide functionality in protonated analytes in a LQIT mass spectrometer. Protonated sulfoxide analytes react with MOP to yield an abundant addition product (corresponding to 37-99% of the product ions), which is accompanied by a much slower proton transfer. The total efficiency (percent of gas-phase collisions leading to products) of the reaction is moderate (3-14%). A variety of compounds with different functional groups, including sulfone, hydroxylamino, N-oxide, aniline, phenol, keto, ester, amino and hydroxy, were examined to probe the selectivity of this reaction. Most of the protonated compounds with proton affinities lower than that of MOP react mainly via proton transfer to MOP. The formation of adduct-MeOH ions was found to be characteristic for secondary N-hydroxylamines. N-Oxides formed abundant MOP adducts just like sulfoxides, but sulfoxides can be differentiated from N-oxides based on their high reaction efficiencies. The reaction was tested by using the anti-inflammatory drug sulindac (a sulfoxide) and its metabolite sulindac sulfone. The presence of a sulfoxide functionality in the drug but a sulfone functionality in the metabolite was readily demonstrated. The presence of other functionalities in addition to sulfoxide in the analytes was found not to influence the diagnostic reactivity.
已开发出一种利用2-甲氧基丙烯（MOP）的气相离子/分子反应的质谱方法，用于在线性四极杆离子阱（LQIT）质谱仪中鉴定质子化分析物中的亚砜官能团。质子化的亚砜分析物与MOP反应生成大量加成产物（占产物离子的37 - 99%），同时伴随着慢得多的质子转移。该反应的总效率（导致产物的气相碰撞百分比）适中（3 - 14%）。研究了多种具有不同官能团的化合物，包括砜、羟胺、N-氧化物、苯胺、苯酚、酮、酯、氨基和羟基，以探究该反应的选择性。大多数质子亲和力低于MOP的质子化化合物主要通过向MOP的质子转移进行反应。发现加合物 - 甲醇离子的形成是仲N-羟基胺的特征。N-氧化物与亚砜一样形成大量MOP加合物，但亚砜可根据其高反应效率与N-氧化物区分开来。通过使用抗炎药舒林酸（一种亚砜）及其代谢物舒林酸砜对该反应进行了测试。很容易证明药物中存在亚砜官能团，而代谢物中存在砜官能团。还发现分析物中除亚砜外的其他官能团的存在不会影响诊断反应性。
