Ultramicroelectrode study without deliberately added electrolyte: Application to the analysis of liquid-liquid extraction processes in dichloromethane

A platinum ultramicroelectrode was used for the in situ study of partition reactions of Bu4NI and Et4NPic between phosphate buffer, pH 7.5, and dichloromethane, without adding supporting electrolyte. Extraction and dissociation constants are determined by voltammetry in the organic phase and compared with those determined by UV-visible spectrophotometry. The results show the significance of the migration effect in the determination of the extracted species by electrochemistry.