Electrochemical Sulfite‐Ion Sensor Using Sm₂CuO₄‐Based Layered Perovskite‐Type Oxide Thick Film

Abstract

Sm 2−x Ce x BO 4 (x = 0, 0.1; B = Fe, Cu) thick films were prepared by an electrophoretic deposition method and applied as sulfite-ion (SO 3 2− ) sensors. Among the oxides, Sm 1.9 Ce 0.1 CuO 4 showed good amperometric response to sulfite ions in the ion concentration range between 1.0 × 10 −5 and 1.0 × 10 −4 M at 30 • C. The applied potential to the electrode should be one of the key factors of high selectivity, and the relatively low potential of +0.2 V versus Ag/AgCl was found to be optimal for the detection of sulfite ions. Good sulfite-ion sensing should be enabled by Cu + in Sm 1.9 Ce 0.1 CuO 4 where SO 3 2− is easily adsorbed.