Amino acid analysis by capillary electrophoresis electrospray ionization mass spectrometry
Amino acid analysis by capillary electrophoresis electrospray ionization mass spectrometry
复制标题
DOI：
10.1021/ac990976y
复制
发表时间：
2000-03-15
影响因子：
7.4
通讯作者：
Heiger, DN
中科院分区：
文献类型：
--
作者：
Soga, T;Heiger, DN
建立了一种基于毛细管电泳-电喷雾电离质谱（CE-ESI-MS）测定未衍生化氨基酸的方法。为了同时分析游离氨基酸，使用低酸性pH条件来赋予全氨基酸正电荷。电解质及其浓度的选择影响氨基酸的分离度和峰形，并选择1 M甲酸作为最佳电解质。同时，鞘液组成对灵敏度有显著影响，当使用50%（v/v）甲醇-水中的5 mM乙酸铵时获得最高灵敏度。质子化的氨基酸大致分离CE和选择性检测的四极杆质谱仪与鞘现在电喷雾电离接口。在优化条件下，在17 min内对蛋白质中常见的19种游离氨基酸和几种生理氨基酸进行了测定。碱性氨基酸的检测限在0.3 - 1.1 μ mol/L之间，酸性和低分子量氨基酸的检测限小于6.0 μ mol/L，进样压力为50 mbar，持续3 s（3 nL），噪声比。该方法简便、快速、选择性好，适用于酱料中游离氨基酸的分析。
A method for the determination of underivatized amino acids based on capillary electrophoresis coupled to electrospray ionization mass spectrometry (CE-ESI-MS) is described. To analyze free amino acids simultaneously a low acidic pH condition was used to confer positive charge on whole amino acids. The choice of the electrolyte and its concentration influenced resolution and peak, shape of the the amino acids, and 1 M formic acid was selected as the optimal electrolyte. Meanwhile, the sheath liquid composition had a significant effect on sensitivity and the highest sensitivity was obtained when 5 mM ammonium acetate in 50% (v/v) methanol-water was used. Protonated amino acids were roughly separated by CE and selectively detected by a quadrupole mass spectrometer with a sheath now electrospray ionization interface. Under the optimized conditions, 19 free amino acids normally found in proteins and several physiological amino acids were well determined in less than 17 min. The detection limits for basic amino acids were between 0.3 and 1.1 mu mol/L and for acidic and low molecular weight amino acids were less than 6.0 mu mol/L with pressure injection of 50 mbar for 3 s (3 nL) at a signal-to-noise ratio of. This method is simple, rapid, and selective compared with conventional techniques and could be readily applied to the analysis of free amino acids in soy sauce.