I'm not sure that I fully understand your question, but the reason that oxygen is often removed from solution before performing cyclic voltammetry (CV) is that the electrochemical reduction of oxygen could interfere with the reaction of interest. In your case, if oxygen is required as a reagent for the enzymatic reaction to proceed, then deaeration is not necessary. It can sometimes be confusing because in electrochemistry, oxygen is not always necessary for an oxidation reaction to occur, e.g., Cu = Cu+ + e-. In other cases, oxygen can be obtained from sources other than molecular oxygen, e.g., water.

Dear Richard A Durst

Thank you very much for your response.

The reaction is an O-dealkylation reaction (oxidation) of an organic molecule performed by an enzyme, in which electrons are given by another molecule and the oxygen is involved. With the CV, I am trying to perform the reaction without the molecule that provides the electrons and instead I would supply current from a potentiostat, but still oxygen is involved. It is necessary to pump oxygen int he solution or can I assumed that the oxygen dissolved in the solution is enough?

On the other hand, If I obtain an oxidation peak with the CV and want to perform the reaction in continuous mode, do I have to fix the voltage or the current of that peak?

People also have recommended that I could use differential pulse voltammetry, what information can be obtained here that is not provided by CV?

Thank you very much.

If you are trying to use EC to perform a reaction, you would probably want to use some sort of controlled potential voltammetry rather than a transient technique such as CV. As you suggest, you can use the CV to elucidate the optimum conditions for the reaction, but not for carrying out the reaction over time. The main advantage of DPV over CV is sensitivity and for your work, I don't think sensitivity should be an issue. Finally, the question of the amount of oxygen depends on the amount of substrate that you are converting in the reaction. It would be a simple matter to bubble air into the solution if the oxygen depletion is a problem.

Thank you very much Richard A Durst for your kind response.

So, what technique do I have to apply to perform the reaction over time? and under which current or potential value from CV?

Briefly, one would first use CV to obtain the optimum conditions for the electrolysis, i.e., potential, solvent, supporting electrolyte, other reagents, etc. After obtaining the best conditions for the reaction, one would then perform a three-electrode, controlled-potential electrolysis to affect the reaction of interest. For details on these methods, I refer you to any of the many excellent texts on electrochemistry.