The direct, in situ, measurement of the flow velocity inside microfluidic devices via electrochemical coupling between two parallel microband electrodes

The extensive development of microfluidic "chips" for the quantitative targeting of analytes necessitates novel protocols and methodologies for the intra muros determination of the solution flow rate. Herein, an electrochemical detection strategy is employed via a series of microelectrodes spatially positioned within a channel microsystem. The transport of a reversible redox species (redox marker) at paired microband electrodes operating in "generator-collector" mode was investigated inside a linear microchannel in the presence and absence of a gravity pressure driven flow. This "generator-collector" assembly enables the characterization of diffusional transport of the redox marker in the absence of flow, and procures, concomitantly, a facile way to estimate, in real time, the mean velocity rate of the fluid in the presence of solution flow.