An equilibrium partitioning model for predicting response to host-guest complexation in electrospray ionization mass spectrometry.
An equilibrium partitioning model for predicting response to host-guest complexation in electrospray ionization mass spectrometry.
复制标题
用于预测电喷雾电离质谱中主客体络合响应的平衡分配模型。
作者：
C. L. Sherman;J. Brodbelt
虽然电喷雾电离质谱（ESI- ms）已经成为一种分析多种类型的主客体络合的强大技术，但问题仍然是ESI产生的离子丰度如何准确地反映溶液中平衡态物种的真实分布。为了更好地理解这种关系，我们开发了一个平衡分配模型来解释各种相互作用，这些相互作用决定了在ESI过程中有多少特定的主客体复合物从溶液转移到气相。通过评估络合反应的同时平衡以及ESI液滴表面和内部的物种分配，可以估计产生的离子丰度。通过ESI四极离子阱质谱仪对18-冠-6与碱金属阳离子配合物的分析，对这一新模型的预测进行了评估和实验验证，并确定单独的结合常数可能不能准确预测所观察到的ESI- ms对不同主客体配合物的响应。
While electrospray ionization mass spectrometry (ESI-MS) has become a powerful technique for analyzing many types of host-guest complexation, questions remain as to just how accurately ion abundances generated by ESI reflect the true distribution of species at equilibrium in solution. To better understand this relationship, an equilibrium partitioning model was developed to explain the various interactions that dictate how much of a particular host-guest complex is transferred from solution into the gas phase in the ESI process. By evaluating the simultaneous equilibria of the complexation reaction and the partitioning of species between the surface and interior of the ESI droplets, one can estimate the ion abundances generated. The predictions of this new model were evaluated and experimentally confirmed through the analysis of the complexes of 18-crown-6 with alkali metal cations in an ESI quadrupole ion trap mass spectrometer, and it was determined that binding constants alone may not give accurate predictions about the observed ESI-MS response to different host-guest complexes.