In this work we elucidated to what extend auxiliary electrochemical working electrodes can be used to determine by electrochemical methods the impact of aCGDE on (i) the structural properties of an auxiliary electrode and (ii) in how far such electrodes can be used as a probe to detect products formed during and after aCGDE. In both cases it was not yet possible to determine these properties during aCGDE. We suggested that changes in the electrode potential of the electrochemical electrodes might be responsible for this observation. This issue has to be addressed more specifically in a more detailed study where the electrode and electrochemical cell geometries are more defined. After the aCGDE we were able to detect qualitatively the presence of H 2 O 2 which was sug-gested to be formed during aCGDE. The concentration in the electrolyte depends on the distance from the electrode as well as on the waiting time after electrolysis. This proof of concept study demonstrates that an electrochemical probe can indeed be used to determine the H 2 O 2 concentration operando and also locally in the electrolyte, which is so far not accessible with other techniques. Overall, such information is crucial for further studies aiming at a more detailed understanding of product formation during aCGDE, the composition of the plasma, the structure formation processes at the plasma electrode or the reaction of these intermediates with species in the electrolyte.