Decoding Voltammograms at the Molecular Frontier: Integration of Voltammetry and Mass Spectrometry

Electrochemical reactions are better understood by gaining insight into the molecular transformations at the electrodes. This paper introduces a straightforward experimental arrangement in which the voltammetry experiment in a standard electrochemical cell integrates with online electrospray-ionization mass-spectrometry. The procedure allows for monitoring of the ions produced at the working electrode. The ionic species sampling is facilitated by a silica capillary embedded in the working electrode and connected directly to the electrospray ionization source. This integration configures real-time monitoring of the ions produced at the working electrode, enhancing our knowledge of the electrochemical process. The methodology is thoroughly described and exemplified by monitoring the reactive intermediates and products that arise during the electrochemical oxidation of carbazole. This design provides an opportunity to study intermediates in electrochemical reactions with advanced mass spectrometry methods such as ion mobility separation or ion spectroscopy.