Coulometric titrations of electrolytes in water by a solid state ionic device using Nafion and Tosflex membranes

Abstract

A solid state ionic device to titrate electrolytes in water was produced, and the performance of the device was examined. The device named the coulometric titration apparatus is a three-component electrochemical cell like an electrodialyzer. The central component, the analyzing room, is a container of the sample solution. The sample solution, 10 −1 M H 2SO 4, NaOH, Na 2SO 4, or 10 −7–10 −2 M Na 2SO 4, is separated from the cathode and the anode room solutions, 10 −2 M H 2SO 4, NaOH, or Na 2SO 4, by Nafion-117 and Tosflex IE-SF34 membranes working as the anion and the cation blocking electrodes, respectively. The quantity of electricity to extract whole electrolytes in the sample solution is evaluated from the peak area of the titration curve. The sample concentration is successfully determined by the calibration curve method, with the quantity of electricity and the sample volume (6 ml) in the range from 10 −1 to 10 −5 M.