Initial Velocities of Hydrated Ions Under an Electropotential Field, Their Molar Masses, and Total Hydration Numbers

The inner hydration shell, where water is electrostricted, has always been the main area of study. But it appears that the bulk water, which is affected by the ion electric field, is not given the same degree of attention. This largely theoretical study aims to develop equation-based models that can be used to calculate the initial velocities of ions when an electrical potential gradient is applied, as well as the total number of water molecules pulled to the ions and their molar masses (including the mass of the electrostricted water). Theoretical and computational approaches were employed to analyze literature-based data. The initial velocity was approximately 3.8 exp. (–8) m/s for cobalt ions and 26 exp. (–8) m/s for oxonium ions. The equivalent total hydration number ranged from 4 for oxonium ions to 60 for cobalt ions. Initial velocities ranged from 1.65 exp. (–8) m/s for epinephrine to 2.88 exp. (–8) m/s for glycinate, and the corresponding total hydration number ranged from 38 for glycinate to 64 for epinephrine. The molar masses of the hydrated ions ranged from 765 g/mol for glycinate to 1,333 g/mol for epinephrine and from 85.81 g/mol for oxonium ions to 1,137.8 g/mol for cobalt ions. The trajectory and biological function of biomolecules can be impacted by their hydrated mass. The lowest and highest velocities are associated with the highest and lowest total hydration numbers per unit charge. Future research could focus on determining the electrophoretic mobilities of all physiologically active biomolecules at physiological pH and body temperature.