ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Voltammetry of resazurin at a mercury electrode

Semiha Çakir and Emine Yilmaz Arslan

Department of Chemistry, Faculty of Arts & Science, Gazi University, 06500 Teknikokullar-Ankara, Turkey

E-mail: scakir@gazi.edu.tr

Received: 4 May 2009  Revised: 12 October 2009  Accepted: 19 October 2009

Abstract: Electrochemical behavior of resazurin on HMDE in Britton-Robinson (B-R) buffers (pH 2.0–10.0) was studied using the square-wave voltammetry (SWV), square-wave adsorptive stripping voltammetry (SWAdSV), and cyclic voltammetry (CV) techniques. The voltammogram of resazurin in B-R buffer at pH < 4.0 exhibited two cathodic reduction peaks. The voltammetric peaks were obtained at −0.144 V (reversible) and −1.250 V (irreversible) at pH 3.2, and correspond to the reduction of resorufin to dihydroresorufin and to the catalytic hydrogen wave, respectively. At pH > 4.0, a new irreversible cathodic reduction peak, assigned to the protonation of N-oxide on the phenoxazin ring, was observed. Electrochemical parameters (I _p/E _p, I _p/v, I _p/pH, I _p/t _acc) of the compound were determined. From the voltammetric data, electrochemical reduction mechanisms for all peaks have been suggested. Maximum peak current for the reversible peak was obtained at pH 4.1. A linear relationship between the current and concentration was determined, and also the lowest detection limit was found as 3.25 × 10⁻⁸ mol L⁻¹ and 1.98 × 10⁻¹⁰ mol L⁻¹ for SWV and SWAdSV, respectively.

Keywords: resazurin - resorufin - square-wave voltammetry - cyclic voltammetry - HMDE

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-010-0007-9

Chemical Papers 64 (3) 386–394 (2010)