Application of the mixed-potential theory to the interpretation of the potential response of a PVC membrane ion-selective electrode for desipramine.

Toshiyuki Osakai, Maya Imoto, Yoshitsugu Sato, Toru Sakaki

Department of Chemistry, Graduate School of Science, Kobe University, Kobe, Japan. osakai@kobe-u.ac.jp

Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2012

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The potential response of an ion-exchanger type PVC ion-selective electrode (ISE) for a drug ion, desipramine(+) (DES(+)), was analyzed by a mixed-potential (MP) theory proposed previously. The transfer of DES(+) and its analogous ions, imipramine(+) (IMP(+)) and neostigmine(+) (NEO(+)), at a micro Ο-nitrophenyl octyl ether/water interface was studied by ion-transfer voltammetry; also, the standard ion-transfer potentials (Δ(O)(W)φ(j)(o)) of the ions were then determined. The application of MP theory with the Δ(O)(W)φ(j)(o) values successfully explained the under-Nernstian response of DES(+)-ISE due to interference from IMP(+) or NEO(+). In this study, a universal method based on numerical calculations was developed for evaluating MP associated with plural interfering ions, which was impossible in the previous method based on analytical equations. Using the universal method, we could well predict the detection limit of DES(+)-ISE theoretically. The MP theory is promising for the sophisticated design of ISEs, which is not due to conventional "trial-and-error" procedures.

Citation

Toshiyuki Osakai, Maya Imoto, Yoshitsugu Sato, Toru Sakaki. Application of the mixed-potential theory to the interpretation of the potential response of a PVC membrane ion-selective electrode for desipramine. Analytical sciences : the international journal of the Japan Society for Analytical Chemistry. 2012;28(6):565-70