Faculty of Chemistry, University of Wrocław, Wrocław, Poland.
J Am Soc Mass Spectrom. 2012 Jun;23(6):1024-8. doi: 10.1007/s13361-012-0359-1. Epub 2012 Mar 9.
Derivatization of peptides as quaternary ammonium salts (QAS) is a known method for sensitive detection by electrospray ionization tandem mass spectrometry. Hydrogens at α-carbon atom in N,N,N-trialkylglycine residue can be easily exchanged by deuterons. The exchange reaction is base-catalyzed and is dramatically slow at lower pH. Introduced deuterons are stable in acidic aqueous solution and are not back-exchanged during LC-MS analysis. Increased ionization efficiency, provided by the fixed positive charge on QAS group, as well as the deuterium labeling, enables the analysis of trace amounts of peptides.
将肽衍生化为季铵盐（QAS）是一种通过电喷雾串联质谱法进行灵敏检测的已知方法。N,N,N-三烷基甘氨酸残基中α-碳原子上的氢可以很容易地被氘取代。交换反应是碱催化的，在较低 pH 值下反应非常缓慢。引入的氘在酸性水溶液中稳定，在 LC-MS 分析过程中不会回交换。QAS 基团固定的正电荷提供了更高的离子化效率，氘标记使得痕量肽的分析成为可能。
