甘草酸钾盐和甘草酸钠盐的电喷雾离子阱质谱研究
Studies on Fragmentation of Potassium Glycyrrhizates and Sodium Glycyrrhizates by Electrospray Ion Trap Mass Spectrometry
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摘要: 用(+)电喷雾离子阱质谱对三元有机弱酸甘草酸的钾盐和钠盐进行了研究。结果显示,甘草酸的一级、二级和三级钾盐或钠盐均可产生很强的质子化分子离子峰;在甘草酸各级钾盐和钠盐的质子化分子离子的二级质谱中,可产生丢失一个葡萄糖醛酸单元的子离子,同时出现双葡萄糖醛酸单元加合相应金属离子的子离子,并且以上子离子均包含与母离子相同数目的相应金属离子。因此,(+)ESI离子阱质谱是区别甘草酸各级钾盐和钠盐的一种有效手段。另外,在甘草酸二钾和甘草酸二钠的(+)ESI-MS一级质谱中,可清楚地观察到一级盐和三级盐的质子化离子,表明甘草酸二盐在水溶液中存在分子间的离子交换Abstract: The fragmentation of potassium and sodium glycyrrhizates was studied by electrospray ion trap mass spectrometry(ESI ITMS). The results indicated that all of the mono , di and tri potassium or sodium glycyrrhizates gave abundant quasi molecular ion M+H + in their (+) ESI ITMS spectra. The daughter ions of losing one glucuronate moiety from the quasi molecular ion and the daughter ion of diglucuronate moiety were exhibited in their ESI MS 2 spectra. All above daughter ions in the MS 2 spectra contained the same number of corresponding metal ions with the parent ion. Therefore, the ESI ion trap mass spectrometry is a useful technique to distinguish mono , di and tri potassium or sodium glycyrrhizates. In addition, quasi molecular ions of mono and tri potassium or sodium glycyrrhizates were displayed in the ESI MS spectra of di potassium or di sodium glycyrrhizate. This indicated the intermolecular exchange of the metal ions in water solutions of the glycyrrhizate disalts.
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