Measurement of the concentration gradient-induced optical beam deflection in the vicinity of a microelectrode

• Published in: BUNSEKI KAGAKU Vol. 47; no. 6; pp. 381 - 385
• Main Authors: WU, Xing-Zheng, YAMAGUCHI, Mamoru, NAGAOSA, Yukio
• Format: Journal Article
• Language: English; Japanese
• Published: Tokyo The Japan Society for Analytical Chemistry 1998; Japan Science and Technology Agency
• Subjects: concentration gradient; electrochemical reaction; microelectrode; optical beam deflection
• ISSN: 0525-1931
• DOI: 10.2116/bunsekikagaku.47.381

A measurement of the concentration gradient-induced optical beam deflection (OBD) in the vicinity of a microelectrode has been attempted. Platinum wires with diameters of 50 μm and 0.5 mm were used as a working microelectrode and a counter electrode, respectively. The reference electrode was a Ag/AgCl electrode. A ferricyanide/ferrocyanide redox reaction was used as a model electrochemical reaction. The applied potential of the Pt microelectrode was controlled using a polarographic analyzer. A probe beam from a diode laser was passed through the vicinity of the Pt microelectrode. Its deflection signal was detected by a position sensor consisting of a knife edge and a photodiode. Two kinds of potential sweeps were carried out. One was a potential step mode, the other was a triangle (cyclic voltammetry) one. Data for a simultaneous measurement of the current and OBD signals indicate that the present OBD method can be used for studying the concentration gradients in the vicinity of a microelectrode.