Murmiliuk Anastasiia, Košovan Peter, Janata Miroslav, Procházka Karel, Uhlík Filip, Štěpánek Miroslav
Department of Physical and Macromolecular Chemistry, Charles University, Hlavova 8, 128 43 Prague 2, Czech Republic.
Institute of Macromolecular Chemistry AS CR, Heyrovský square 2, 162 06 Prague 6, Czech Republic.
ACS Macro Lett. 2018 Oct 16;7(10):1243-1247. doi: 10.1021/acsmacrolett.8b00484. Epub 2018 Sep 24.
In recent experiments, the "local pH" near polyelectrolyte chains was determined from the shift in the effective acidity constant of fluorescent pH indicators attached to the macromolecules. This indirect determination raises the question if the analyzed quantity was indeed the "local pH" and what this term actually means. In this study, we combined experiments and simulations to demonstrate that the shift in ionization constant is slightly lower than the difference between the pH and the "local pH". This offset is caused by correlations between fluctuations in chain conformation, small-ion distribution, and fluorophore ionization.
在最近的实验中，通过连接到大分子上的荧光pH指示剂有效酸度常数的变化来测定聚电解质链附近的“局部pH”。这种间接测定引发了一个问题，即所分析的量是否确实是“局部pH”，以及这个术语实际意味着什么。在本研究中，我们结合实验和模拟来证明电离常数的变化略低于pH与“局部pH”之间的差值。这种偏移是由链构象波动、小离子分布和荧光团电离之间的相关性引起的。
