American Chemical Society
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Porous Teflon Ring-Solid Disk Electrode Arrangement for Differential Mass Spectrometry Measurements in the Presence of Convective Flow Generated by a Jet Impinging Electrode in the Wall-Jet Configuration

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journal contribution
posted on 2016-02-20, 19:04 authored by Imre Treufeld, Adriel Jebin Jacob Jebaraj, Jing Xu, Denis Martins de Godoi, Daniel Scherson
A porous Teflon ring|solid disk electrode is herein described specifically designed for acquiring online mass spectrometric measurements under well-defined forced convection created by liquid emerging from a circular nozzle impinging on the disk under wall-jet conditions. Measurements were performed for the oxidation of hydrazine, N2H4, in a deaerated phosphate buffer electrolyte (pH 7) on Au, a process known to yield dinitrogen as the product. The N2+ ion currents, measured by the mass spectrometer, i(N2+), as well as the corresponding polarization curves recorded simultaneously displayed very similar s-like shapes when plotted as a function of the potential applied to the Au disk. In fact, the limiting currents observed both electrochemically and spectrometrically were found to be proportional to [N2H4]. However, the limiting values of i(N2+) did not increase monotonically with the flow rate, νf, reaching instead a maximum and then decreasing to values independent of νf. This behavior has been attributed in part to hindrances in the mass transport of gases through the porous materials.