Fabrication and optimization of a multielectrode microfluidic electrochemical flow cell for fast and dynamic detection of reaction products

Construction and experimental validation of electrochemical cells with multiple electrodes in a microfluidic channel is described. Details of the fabrication of the electrodes and polydimethylsiloxane channel using soft lithography methods are given. Calibration of the collection efficiencies and transit times between electrodes validate the use of these cells for fast electrochemical detection of soluble species. Mass transit times between two electrodes down to 3 ms with a flow rate of 200 µL min^-1 are demonstrated. We demonstrate that there is an upper limit in the electrode width to channel height ratio depending on the electrolyte conductivity. A recommendation for the maximum electrode width to channel height ratio is presented. The electrode width is recommended to not exceed four times the height of the channel in 0.1 M H₂SO₄. We also demonstrate operating strategies to minimize the impact of oxygen in air, optimization of stepping motor syringe pump parameters, electrolyte switching, and show how to deposit catalyst particles on a channel electrode.

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  Fabrication methods are given for all components of microfluidic flow cells with multiple electrodes
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  Conditions are given for improved operation, including geometry, pumping, and electrical parameters.