基于极性反转电压策略的高效纳喷雾负离子源研制

High-efficiency ionization method based on polarity-reversing high voltage strategy for nano-electrospray

目的:当溶剂为纯水溶液时,在电喷雾离子化的过程中常常会因为过高的电压而形成电晕放电,从而导致质谱检测分析中的离子电流不稳定和灵敏度下降,尤其是在负离子模式中放电现象更为明显。方法:利用基于极性反转电压策略的纳喷雾离子化方法来形成电喷雾。结果:在负离子模式下,肌红蛋白、细胞色素c和胰岛素被成功的检测到,并且检出质谱图显示三种蛋白的谱峰均是由去质子化的谱峰构成的,这极有利于提高质谱检测的灵敏度。此外,对三种蛋白质的检出限进行检测,发现到最低检出限达到10-9 mol数量级。结论:我们的方法实现在负离子模式下蛋白质的高灵敏度检测,可以为未来的负离子模式下基于质谱的蛋白质组学分析提供支持。

Aims: The corona discharge often formed due to high voltages in the process of electrospray ionization when the solvent is pure aqueous solution. And this results in the instability of ionization and the decrease of sensitivity. Especially in negative polarity, the discharge phenomenon is more obvious. Methods: A polarity-reversing high voltage strategy for the generation of nano-ESI(PR-nESI) was used. Results: Myoglobin, cytochrome c and insulin were detected successfully in negative polarity. And mass spectra showed that the peaks of three proteins were composed of deprotonated ion peaks, which was greatly beneficial to increase the sensitivity of mass spectrometry. Moreover, the detection limit of the three proteins was detected;and it was found that the minimum detection limit reached the order of 10-9 mol. Conclusions: Our method achieved high sensitivity detection of proteins in negative polarity, which could provide support for mass spectrometry based analysis of proteomics in negative polarity in the future.