Electrochemical Oxidation of Sulfasalazine at a Glassy Carbon Electrode

• Published in: Electroanalysis (New York, N.Y.) Vol. 26; no. 5; pp. 924 - 930
• Main Authors: Buoro, Rafael M., Diculescu, Victor C., Lopes, Ilanna C., Serrano, Silvia H. P., Oliveira-Brett, Ana Maria
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.05.2014; WILEY‐VCH Verlag
• Subjects: Differential pulse voltammetry; Diffusion; Electrochemical oxidation; Electrodes; Electrolytes; Glassy carbon; Glassy carbon electrode; Oxidation; Oxidation mechanism; Spectra; Sulfasalazine; UV-vis spectrophotometry
• ISSN: 1040-0397; 1521-4109
• DOI: 10.1002/elan.201400053

Sulfasalazine (SSZ) is a pharmaceutical compound used for the treatment of rheumatoid arthritis. The electrochemical oxidation of SSZ at a glassy carbon electrode was studied by cyclic, differential pulse and square wave voltammetry in a wide pH range. For electrolytes with pH<11.0, the oxidation is an irreversible, diffusion‐control, pH‐dependent process that involves the transfer of one electron and one proton from the hydroxyl group of the salicylic moiety. For pH>11.0 the oxidation is pH‐independent, and a pKa≈11 was determined. The formation of a quinone‐like oxidation product that undergoes two electrons and two protons reversible redox reaction was observed. Also, UV‐vis spectra of SSZ were recorded as a function of supporting electrolytes pH. An electrochemical oxidation mechanism was proposed.