电喷雾质谱法研究氨基酸的质谱碎裂及其与人参皂苷Rb3的相互作用

用串联质谱法研究了18种常见氨基酸在正离子和负离子模式下的质谱碎裂规律. 结果表明, 在正离子模式下的分子离子峰强度比在负离子模式下的高一个数量级, 氨基酸α-C上的羧基和氨基容易脱掉. 在正离子和负离子模式下都有两种裂解机理. 用电喷雾软电离技术研究了人参皂苷Rb3与18种氨基酸的非共价相互作用, 并采用直接计算的方法得出这些非共价复合物的解离常数. 结果表明, 在水介质中,与其它氨基酸相比, 酸性氨基酸和碱性氨基酸与人参皂苷结合更稳定.

Studies on Fragmentation Pathways of Amino Acids and Their Interactions with Ginsenoside Rb3 by Spectrospray Ionization Mass Spectrometry

Electrospray ionization tandem mass spectrometry(MS/MS) was applied to study fragmentation pathways of 18 kinds of α-amino acids in positive and negative ion mode. The groups —NH2 and —COOH which joined to α-C were found to be more inclined to be fragmented, but not the side chain. The peak intensities of molecular ions in positive ion mode are stronger than those in negative mode. Electrospray ionization mass spectrometry was applied to study the noncovalent interaction of ginsenoside Rb3 and 18 kinds of amino acids. The dissociation constants were calculated directly based on the peak intensities. It is indicated from the experimental results that the complexes of acidic or alkaline amino acids and ginsenosides are more stable than those of other amino acids.