电喷雾质谱法中K^+加合离子受Cs^+影响及在牛膝多糖分子 量分布测定中的应用

以测定牛膝多糖的分子量分布为例，研究了在Cs^+存在情况下，电喷雾(ESI)/飞行时间质谱法(TOF-MS)中出现加合离子(adductions)的规律。实验中发现，牛膝多糖样品中加入适量的Cs^+，可影响其与Na^+，K^+加合离子的相对丰度，使K^+加合离子成为几乎唯一的加合离子形式，并获得了满意结果。另外讨论了Cs^+浓度、喷管电压(nozzlepotential)对这一现象的影响。

Effect of Cs^+ on K^+ adduct ions in electrospray mass spectrometry and its application in measurement of molecular weight distribution for achyranthes bidentata polysaccharides

Relative abundance of adduct ions was studied in measuring molecular weight distribution of achyranthes bidentata polysaccharides using electrospray ionization (ESI)/time-of -flight mass spectrometry (TOF MS) in the presence of Cs^+. The relative abundance of K^+ adduct ions, (C~6H~1~0O~5)~n+H~2O+H^++K^+, was affected by Cs^+ and become an almost unique form of adduct ions at suitable concentrations of Cs^+. This can greatly increase sensitivity and simplify the spectrum. Measuring the molecular weight distribution of achyranthes bidentata polysaccharides thus became easier, and electrospray ionization found a new application. The concentration of Cs^+ and nozzle potential were key factors that affect the relative abundance of K^+ adduct ions.