Electrochemical Filter To Remove Oxygen Interference Locally, Rapidly, and Temporarily for Sensing Applications

Abstract

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Local removal of oxygen for NAD(P)+ detection in aerated solutions

“…In accordance to the higher reduction current (in absolute value) on the two Pt-layer electrode, O2 removal was more efficient than with a single Pt grid, as revealed by the less significant residual currents, lower than 0.4 µA at 0.6 V. After degassing the solution under N2 bubbling (blue curve), the current recorded on GCE (with oxygen filter WE2 on OFF position) was very similar to that obtained in aerated solution with the 2-grid layer (with oxygen filter WE2 in the ON position), which demonstrates the efficiency of the electrochemical scrubber for oxygen removal. According to a simple modeling of the electrochemical filter, the amount of residual oxygen can be rapidly lowered to less than 1 % of its initial concentration in less than few minutes [27]. This result is very promising in view to conducting experiments sensitive to the presence of oxygen, such as the electrochemical detection of NAD(P) + .…”

“…The second drawback is related to pH modification in the small volume of solution that is between the filter and the sensor surface. Measuring this local pH is not trivial and we have considered this question in a recent report based on simple calculations: it came out that a pH shift could be contained by using a small buffer concentration [27].…”

“…It was obtained by diazonium electrografting of aminobipyridine followed by complexation of RhCp*Cl. It was covered by an electrochemical filter that allowed for local elimination of oxygen, according to an idea that we reported very recently [27]. The effectiveness of oxygen removal was first checked in a background electrolyte solution and then in the presence of NAD(P) + to evaluate its interest for reductive cofactor regeneration in aerated solutions.…”

Electroanalytical metal sensor with built-in oxygen filter

“…However, this procedure provokes a significant loss of the detection level since the measurable peak is inversely proportional to the stripping current. A novel solution of removing the oxygen by an electrochemical oxygen filter for the purpose of omitting the nitrogen purging step has been introduced recently [18,19]. This approach provided a rapid and reliable way of locally removing the oxygen near the sensor surface.…”

“…The application of a given potential at the platinum grid induces the oxygen reduction locally, in the vicinity of the sensor. This approach was successfully studied on the model analyte, paraquat [19] and detection of NAD(P) + in a biosensing application [18].…”