Guan Z, Drader J J, Campbell V L, Laude D A
Department of Chemistry and Biochemistry, University of Texas at Austin 78712, USA.
Anal Chem. 1995 Apr 15;67(8):1453-8. doi: 10.1021/ac00104a023.
A single population of multiply charged protein ions formed by electrospray ionization is held in a trapped ion cell and remeasured continuously by Fourier transform ion cyclotron resonance (FTICR) mass spectrometry while undergoing multiple reactions with diethylamine. In a first example, electrosprayed horse myoglobin with an average of 16 attached protons is reacted with base at a pressure of 1.5 x 10(-8) Torr for a period of 60 s. A total of 31 spectra acquired with a duty cycle of 2 s exhibit the charge state-dependent formation of up to three diethylamine adducts and removal of up to nine protons. A realtime measuring experiment is then conducted over a 1 h period to observe charge stripping of electrosprayed myoglobin ions, leaving as few as seven charges. Realtime monitoring is used to evaluate the effect of reagent gas pressure on adduct formation and is used in conjunction with high mass resolution FTICR detection to resolve the isotopic peaks within individual charge states of adduct spectra. The attractive features of real-time reaction monitoring include a dramatic reduction in experiment time and sample consumed while concurrently observing long-lived intermediates and reaction products as they form.
通过电喷雾电离形成的单一组多重带电蛋白质离子群被保存在一个俘获离子池中，并在与二乙胺发生多重反应的过程中，由傅里叶变换离子回旋共振（FTICR）质谱仪连续重新测量。在第一个例子中，平均带有16个附加质子的电喷雾马肌红蛋白在1.5×10⁻⁸托的压力下与碱反应60秒。以2秒的占空比采集的总共31个光谱显示出电荷态依赖性地形成多达三个二乙胺加合物，并去除多达九个质子。然后在1小时内进行实时测量实验，以观察电喷雾肌红蛋白离子的电荷剥离情况，最终只剩下七个电荷。实时监测用于评估反应气压力对加合物形成的影响，并与高质量分辨率FTICR检测结合使用，以解析加合物光谱各个电荷态内的同位素峰。实时反应监测的吸引人之处包括显著减少实验时间和样品消耗，同时在长寿命中间体和反应产物形成时对其进行观察。
