Automated electrode array for in-channel electrochemical detection

This work presents a low-cost microfluidic device with sensitive, in-channel electrochemical detection capabilities in microfluidic device. This is accomplished using in-channel gold microelectrodes. The detection unit is composed of (i) the working electrodes (WE) with (ii) a common pseudo-reference electrode (RE) in gold and (iii) a counter electrode (CE) made with indium tin oxide (ITO) on a glass substrate. A redox solution ferrocyanide/ferricyanide was flowed through the microfluidic channel in order to test sensing capabilities using cyclic voltammetry (CV). This solution was confined by an electrochemically inactive solution (ultra-pure water) in the same channel. The position of the interface between the redox solution and the confinement solution could be changed via the ratio between their volumetric flow rates. Cyclic voltammetry allowed the detection of electro active species with reduction current of 150 nA.