mz8b00484_si_001.pdf (1.04 MB)
Local pH and Effective pK of a Polyelectrolyte Chain: Two Names for One Quantity?
journal contribution
posted on 2018-09-21, 21:18 authored by Anastasiia Murmiliuk, Peter Košovan, Miroslav Janata, Karel Procházka, Filip Uhlík, Miroslav ŠtěpánekIn 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.