Abstract
Iodide ion in acidic solution reacted with the copper electrode of a piezoelectric quartz crystal to form copper (I) iodide. As the frequency of the crystal decreased with increasing the weight of the electrode adsorbed the copper (I) iodide, iodide ion could be determined using the piezoelectric quartz crystal. Copper (I) iodide on the electrode could be washed out with ammonium hydroxide solution for the successive experiments. All solutions were placed in a thermostat (25°C) and flowed on the electrode at the rate of 2.2 ml/min. The iodide sample solution was flowed in the cell after the shift in the frequency of the crystal attained a constant rate in the flow of blank solution. The frequency change resulted from the iodide was obtained from the difference between the maximum and minimum frequency obtained before and after the flow of the sample solution. Iodide of (15) × 10-5 M could be determined by the calibration curve prepared by the same method.
