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Hyphenation of electrochemistry (EC) and mass spectrometry (MS) is a growing research field with particular importance for bioanalytical applications. It opens the way for studying reaction mechanisms and metabolic pathways of biological compounds and drugs. Electrochemical conversion of sample molecules prior to MS analysis gives rise to short-lived intermediates and products naturally occurring in biological systems, which leads to better understanding of physiological processes. Numerous interesting and attractive studies in this field have been published so far demonstrating potential of EC-MS coupling. The combination with separation system such as liquid chromatography or capillary electrophoresis widens the scope of application providing additional information about compounds of interest. The combination of EC with liquid chromatography has been the most frequently used hyphenated system due to the simplicity of coupling to mass spectrometric detection. In terms of bioanalytical applications capillary electrophoresis offers some advantages and is a complementary technique to liquid chromatography. This review summarizes recent developments in this field from both instrumental and application perspectives. A rather new approach of coupling electrochemistry-capillary electrophoresis-mass spectrometry and its potential for bioanalysis is presented.

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The oxidative behavior of cyclic nucleotides, important intracellular second messengers, was investigated. Guanosine‐3′,5′‐cyclic monophosphate, adenosine‐3′,5′‐cyclic monophosphate and cytidine‐3′,5′‐cyclic monophosphate were subjected to electrochemical oxidation at different pH using boron doped diamond (BDD) and screen‐printed carbon (SPC) electrodes. While oxidation on SPC electrodes proceeds only via direct analyteelectrode electron transfer, BDD involves in addition the action of hydroxyl radicals, formed at the electrode surface. Generated oxidation products were analyzed by liquid chromatography coupled to high resolution mass spectrometry (LC‐MS). As an alternative electrochemically assisted injectioncapillary electrophoresismass spectrometry was used as a means for product generation and identification. The results obtained indicate that experimental conditions as well as the presence of the cyclic phosphate group influence the oxidative pathway of cyclic nucleotides. Simplicity of the experiment and the absence of complex biological matrices are the main advantages of electrochemistry over other techniques, employed for investigation of oxidative stress. Elucidation of oxidation products and reaction mechanism is an important aspect of therapeutic strategies of numerous severe diseases.