Electrochemistry (EC) coupled to mass spectrometry (MS) in the last years has been proven to serve as a promising tool in the field of metabolism research. In conventional animal based metabolism studies, the identification of especially short living, reactive intermediates is difficult due to their binding to cell components such as proteins. With EC/MS as a purely instrumental approach, most oxidative metabolism reactions can be simulated. This way, it is possible to study the phase I metabolism of xenobiotics including the identification of reactive intermediates. By extending the setup and adding a solution of a biomolecule like a peptide, protein or DNA immediately after EC oxidation, the phase II metabolism can be studied and toxicity assessment can be performed as well.