What protein charging (and supercharging) reveal about the mechanism of electrospray ionization.
What protein charging (and supercharging) reveal about the mechanism of electrospray ionization.
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DOI：
10.1007/s13361-014-0965-1
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发表时间：
2014-10
影响因子：
3.2
通讯作者：
Loo, Joseph A.
中科院分区：
文献类型：
--
作者：
Loo, Rachel R. Ogorzalek;Lakshmanan, Rajeswari;Loo, Joseph A.
了解电喷雾电离的充电机制是克服离子抑制或有限的动态范围等缺点和解释增压等现象的核心。为此，我们探索积累的观察揭示了电喷雾的机制。我们引入了电喷雾电离（和其他电离方法）的中间区域的想法，以解释溶液电荷态分布（CSD）与ESI-MS观察到的电荷态分布（后者携带更多电荷）不相关的事实，气相反应可以减少，但不会增加充电的程度。该区域包含属性，例如，碱度介于溶液和气相之间。假设液滴物种在高电场内的扩散导致描述离子发射的方程类似于来自平衡分配模型的方程。该方程成功地预测了许多趋势，包括CSD转移到较高的m/z的浓缩分析物和转移到较低的m/z的喷雾采用较小的发射器开口直径。从这个角度来看，可以制定一个单一的机制来解释如何促进分析物充电（“增压”），如m-NBA，环丁砜，和3-硝基苯甲腈试剂增加分析物电荷从“变性”和“天然”溶剂系统。这表明，添加剂的布朗斯台德碱度是负相关的，他们的能力，以转移CSD到较低的m/z在正ESI，作为布朗斯台德酸度为负ESI。因为增压剂减少了分析物溶液的电离，多余的喷雾电荷被赋予了携带较少相反电荷的蒸发离子。布朗斯台德碱度（或酸度）决定了有多少ESI电荷损失到试剂中（无法蒸发分析物）。
Understanding the charging mechanism of electrospray ionization is central to overcoming shortcomings such as ion suppression or limited dynamic range and explaining phenomena such as supercharging. Towards that end, we explore what accumulated observations reveal about the mechanism of electrospray. We introduce the idea of an intermediate region for electrospray ionization (and other ionization methods) to account for the facts that solution charge state distributions (CSDs) do not correlate to those observed by ESI– MS (the latter bear more charge) and that gas phase reactions can reduce, but not increase the extent of charging. This region incorporates properties, e.g., basicities, intermediate between solution and gas phase. Assuming that droplet species polarize within the high electric field leads to equations describing ion emission resembling those from the equilibrium partitioning model. The equations predict many trends successfully, including CSD shifts to higher m/z for concentrated analytes and shifts to lower m/z for sprays employing smaller emitter opening diameters. From this view, a single mechanism can be formulated to explain how reagents that promote analyte charging (“supercharging”) such as m–NBA, sulfolane, and 3–nitrobenzonitrile increase analyte charge from “denaturing” and “native” solvent systems. It is suggested that additives’ Brønsted basicities are inversely correlated to their ability to shift CSDs to lower m/z in positive ESI, as are Brønsted acidities for negative ESI. Because supercharging agents reduce an analyte's solution ionization, excess spray charge is bestowed on evaporating ions carryingfewer opposing charges. Brønsted basicity (or acidity) determines how much ESI charge is lost to the agent (unavailable to evaporating analyte).
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DOI：
10.1007/s13361-011-0319-1
发表时间：
2012-03-01
影响因子：
3.2
作者：
Douglass, Kevin Aart;Venter, Andre R.
通讯作者：
Venter, Andre R.
影响因子：
2.9
作者：
Grimm, Ronald L.;Beauchamp, J. L.
通讯作者：
Beauchamp, J. L.
影响因子：
7.4
作者：
Ferguson, Carly N.;Benchaar, Sabrina A.;Miao, Zhixin;Loo, Joseph A.;Chen, Hao
通讯作者：
Chen, Hao
影响因子：
7.4
作者：
Hedges, Jason B.;Vahidi, Siavash;Konermann, Lars
通讯作者：
Konermann, Lars
影响因子：
2
作者：
Gabelica, V;Vreuls, C;De Pauw, E
通讯作者：
De Pauw, E