The effect of infrared radiation on the potentiometric behaviour of gold-wire electrodes

Abstract

Gold-wire and infrared-irradiated gold-wire electrodes have been used in potentiometric titrations in conjunction with the saturated calomel electrode or molybdenum-wire reference electrode. The step heights obtained in pH titrations by using the gold electrode are less than those obtained with other pH electrodes. In iron(II)-potassium dichromate titrations, the performance of the gold electrode is comparable with that of the platinum electrode, whereas in iron(II)-potassium permanganate titrations, a double step is obtained with reductant and oxidant solutions of 10^–5 and 10^–4N, respectively.

When the infrared-irradiated electrode is used in pH titrations, the curve height increases by 200 mV. A similar increase is also obtained for iron(II)-potassium dichromate titrations, but not for iron(II)-potassium permanganate titrations. However, the asymmetry in the permanganate titration vanishes, giving rise to a single curve. The reasons for this behaviour are discussed.