Zusammenfassung
Bile acids and sterols in general have long been considered practically inactive for direct redox processes. Herein, a novel way of electrochemical oxidation of primary bile acids is reported, involving an initial acid-induced dehydration step, as confirmed by capillary electrophoresis-mass spectrometry, thereby extending the electrochemical activity of the steroid core. Oxidation potentials were ...
Zusammenfassung
Bile acids and sterols in general have long been considered practically inactive for direct redox processes. Herein, a novel way of electrochemical oxidation of primary bile acids is reported, involving an initial acid-induced dehydration step, as confirmed by capillary electrophoresis-mass spectrometry, thereby extending the electrochemical activity of the steroid core. Oxidation potentials were found to be ca + 1.2 V vs. Ag/AgNO3 in acetonitrile on boron doped diamond, glassy carbon, and platinum electrodes in a mixed acetonitrile-aqueous medium employing perchloric acid as a chemical reagent, and as a supporting electrolyte for the voltammetric measurements. The chemical step proved to be effective only for primary bile acids, possessing an axial 7 alpha-hydroxyl group, which is a prerequisite for providing a well-developed voltammetric signal. Preliminary results show that other steroids, e.g., cholesterol, can also be oxidized by employing a similar approach.