EFFECT OF ELECTROLYTE ENVIRONMENT ON DIVALENT TARTRATE ION MOBILITY

Abstract

The variation of the electrophoretic mobility, uT, of divalent tartrate ion with changing electrolyte environment has been studied. Mobilities were determined from boundary velocity measurements at 1.00 °C in the Tiselius electrophoresis apparatus. The solutions used, which were adjusted to pH 8.3–8.5, were principally either 0.04667 M C2T or 0.01 M C2T–0.11 M CA, where C+, T=, and A− are, respectively, a univalent cation, divalent tartrate ion, and a univalent anion. Relative viscosities, ηrcl, of a number of these solutions were also obtained. For a given anion environment, the variation of uT with changing cation is characterized by a minimum at sodium and a maximum at tetramethylammonium for a series of six alkali metal and tetraalkylammonium ions. For the alkali metal cations and for tetrapropylammonium ion, uT undergoes a distinct decrease when the solution is changed from 0.04667 M C2T to 0.01 M C2T–0.11 M CCl. For all solutions containing an anion A−, uT decreases with increasing hydrocarbon content of A− for a given cation. Possible ion association, obstruction, and ion–solvent interaction effects are considered.