Determination of Selenium(IV) by a Photooxidized 3,3'-Diaminobenzidine/Perfluorinated Polymer Mercury Film Electrode

摘要

A new, and easily fabricated, chemically modified elec-Irode for the determination of selenium(lV) was examined by cathodic square-wave stripping voltammetry. This new electrode consisted of an anion-exchange perfluorinated polymer (Tosfiex) coated thin mercury film electrode containing photooxidized 3,3’-diaminobenzidine (ODAB). The coating solution of Tosfiex and ODAB was spin-coated on a glassy carbon electrode followed by electroplating of a thin film of mercury. During the preconcentration, ODAB was reduced electrochemically and selenium was accumulated simultaneously onto the electrode by inter-acting with the reduced ODAB. After a 5-min preconcen-tration period, linear response was observed from 0.5 to 50 ppb selenium, and the detection limit was 0.1 ppb. The proposed method does not require a darkened room, which was required in many of the previous methods involving 3,3’-diaxninobenzidine. In addition, the resis-tance to interference from surface-active compounds was improved by incorporating Tosfiex in the film.