Investigation on mechanisms for the electrooxidation of some bile pigments by spectroelectrochemistry

The electrooxidation behavior of bilirubin (BR), biliverdin (BV), purpurin (Pu), and choletelin (Ch) in dimethylformamide (DMF) have been investigated by voltammetry, in situ electron spin resonance (ESR) thin‐layer spectroelectrochemistry and especially in situ rapid scan spectrometer. Radical cations and multiple chemical reactions were found to occur during the electrooxidation processes of these bile pigments The proposed oxidation mechanism of BR corresponds to mixed processes of ECECC and ECECEC, while that of BV and Pu are all ECECC.