An investigation of the Fe3+- sulphonated pyrogallol system in aqueous solutions

Abstract

The electrochemical behaviour of the Fe3+-sulphonated pyrogallol (SP) complex was investigated and its composition and stability constants were determinated at pH 2.30. It was found by voltammetric and spectrophotometric measurements that Fe3+ and SP form a complex of the ML2 type, which is relatively stable during the first 30 minutes. The optimal pH value for complex formation is between 2.30 and 2.80. The relative stability constants determined by voltammetric and spectrophotometric measurements are log b2 = 5.08±0.26 and log b2 = 6.31±0.04, respectively.

Keywords

• cyclic voltammetry
• spectrophotometry
• Fe3+ ions
• complex
• sulphonated pyrogallol