Influence of hydrophilic additives on the signal intensity in electrospray ionization of flavonoid glycosides
Influence of hydrophilic additives on the signal intensity in electrospray ionization of flavonoid glycosides
复制标题
亲水添加剂对黄酮苷电喷雾电离信号强度的影响
DOI：
10.1002/rcm.8914
复制
发表时间：
2020
期刊：
影响因子：
--
通讯作者：
M. Takayama
中科院分区：
文献类型：
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作者：
A. Kegashima;A. Motoyama;M. Takayama
研究了亲水添加剂甘氨酸、葡萄糖和甘油对黄酮类苷和非还原性双糖电喷雾电离信号强度的影响。过量的甘氨酸由于其较强的水化能力，对ESI溶液信号强度的影响大于葡萄糖和甘油。方法在选定的离子监测模式和扫描模式下，对所制备的过量添加剂添加后的ESI信号响应进行评价。所有的质谱数据都是在负离子模式下获得的，因为负离子模式是推荐的糖类化合物。结果在黄酮类苷和海藻糖的ESI溶液中加入甘氨酸可增强信号强度，而葡萄糖和甘油的加入对信号强度影响不大。芦丁的信号强度高于柚皮苷和橙皮苷，这与它们在ESI溶液中的溶解度有关。海藻糖分子与甘氨酸分子特异性相互作用形成1:1的海藻糖-甘氨酸复合物，而类黄酮苷不产生这种复合物离子。结论添加甘氨酸后，糖的ESI信号增强可能是由于其较强的水合能力，两性离子甘氨酸分子的去质子化羧基氧与水氢原子强相互作用，产生较强的水合焓。因此，甘氨酸分子使分析物免于与ESI液滴中的水分子溶剂化。
RationaleThe influence of hydrophilic additives glycine, glucose, and glycerol on electrospray ionization (ESI) signal intensity of flavonoid glycosides and a nonreducing disaccharide is examined. The addition of excess glycine to the ESI solution would affect signal intensity more than glucose and glycerol due to its strong hydration capability.MethodsThe ESI signal response upon the addition of excess additives prepared was estimated in both selected ion monitoring and scan mode. All the mass spectrometry data were acquired in negative ion mode, because negative ion mode is recommended for saccharide compounds.ResultsThe addition of glycine to the ESI solution of flavonoid glycosides and trehalose enhanced signal intensity, whereas the addition of glucose and glycerol had little effect. The signal intensity of rutin was higher than that of naringin and hesperidin, in accordance with their solubility in ESI solution. Trehalose molecules specifically interacted with glycine molecules to form a 1:1 trehalose–glycine complex, whereas the flavonoid glycosides did not produce such complex ions.ConclusionsThe ESI signal enhancement of the saccharides with the additive glycine can be explained by its strong hydration capability, with the deprotonated carboxylic oxygens of zwitterionic glycine molecules strongly interacting with water hydrogen atoms resulting in strong hydration enthalpy. Consequently, glycine molecules set the analytes free from solvation with water molecules in the ESI droplets.