Kane R S, Glink P T, Chapman R G, McDonald J C, Jensen P K, Gao H, Pasa-Tolić L, Smith R D, Whitesides G M
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
Anal Chem. 2001 Aug 15;73(16):4028-36. doi: 10.1021/ac010173m.
This paper describes the use of capillary electrophoresis (CE), and coupled CE and mass spectrometric techniques, to measure the values of the pKa of the amino groups of the aminoglycoside antibiotic amikacin and of its acetylated derivatives. These values of pKa (8.4, 6.7, 9.7, 8.4) were determined by measuring the electrophoretic mobilities of the molecules as a function of pH; they are within 0.7 unit of certain values reported in the literature (by 13C and 15N NMR spectroscopies) but resolved ambiguities left by these earlier studies. The range of values of pKa of amino groups also indicates the complex dependence of the acidity of a functional group (and thus the extent of ionization at a specified value of pH) on the molecular environment of that group.
本文描述了使用毛细管电泳（CE）以及联用CE和质谱技术来测量氨基糖苷类抗生素阿米卡星及其乙酰化衍生物氨基的pKa值。这些pKa值（8.4、6.7、9.7、8.4）是通过测量分子的电泳迁移率随pH的变化来确定的；它们与文献中（通过13C和15N核磁共振光谱法）报道的某些值相差在0.7个单位以内，但解决了这些早期研究留下的模糊问题。氨基的pKa值范围还表明了官能团酸度（以及在特定pH值下的电离程度）对该基团分子环境的复杂依赖性。
