Analytical Sciences

Electropolymerization of Azure A and pH Sensing Using Poly(azure A)-modified Electrodes

Kyoko SUGIYAMA,* Kazuhiro WATANABE,* Sachiko KOMATSU,* Kentaro YOSHIDA,** Tetsuya ONO,** Tsutomu FUJIMURA,* Yoshitomo KASHIWAGI,** and Katsuhiko SATO*,***

*Faculty of Pharmaceutical Science, Tohoku Medical and Pharmaceutical University, 4-4-1 Komatsushima, Aoba, Sendai, Miyagi 981-8558, Japan
**School of Pharmaceutical Sciences, Ohu University, 31-1 Misumido, Tomita-machi, Koriyama, Fukushima 963-8611, Japan
***Department of Creative Engineering, National Institute of Technology, Tsuruoka College, 104 Sawada, Inooka, Tsuruoka, Yamagata 997-8511, Japan

A modified electrode was developed by immobilizing poly(azure A) (pAA) onto the surface of a glassy carbon electrode via the electropolymerization of azure A (AA). The pAA immobilized on the electrode exhibited redox response during cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The redox reaction obeyed the Nernst equation because of the involvement of H⁺ ions. In addition, the peak potential was shifted according to the solution pH. The shifts of the oxidation peak potential could be more easily observed using DPV than when using CV, indicating that the developed electrode could be useful as a pH sensor. This pH measurement method can be successfully applied in the pH range of 1 to 10 and can be successfully repeated more than 50 times.

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