Abstract: A method to optimize the amperometric detection in a microsystem consists in limiting the detection to times when the diffusion layer (18-20) of the analyte to detect remains smaller than the microchannel (7) height. The charge detected during the second part of the amperometric measurement (which corresponds to the integral of the measured current over the corresponding time period) can also be considered so as to remove the contribution of the capacitive current and, when applicable, of the current resulting from the reduction or oxidation of the analyte molecules present in a recess above the electrode at the beginning of the detection. A microfluidic amperometric sensor for performing the method comprises at least one microchannel (7) having at least one electrode (15-17), integrated in one wall of the microchannel, and having a characteristic length or radius which is smaller than half the microchannel height.

Abstract: An electrochemical microfluidic device has one or a plurality of microstructures, such as a microchannel, in which an electrically conductive means is integrated to reduce the ohmic resistance within the microstructure and hence to improve electrochemical measurements particularly when large current densities are involved. The electrically conductive means can be connected as a counter-electrode and can be used to re-generate the product of the reaction occurring at the working electrode. A method of fabricating electrochemical microfluidic devices comprising such an electrically conductive means is also disclosed. The invention may particularly be used in all electrochemical sensor applications where detection is performed in small volumes.

Abstract: An electrochemical flow monitoring device comprises a microfluidic system comprising at least one covered microchannel (3) having an inlet (4) and an outlet (5). A pressure difference is applied between the inlet and the outlet of the microfluidic system, for example by changing the relative heights of the inlet (4) and outlet (5), such as to generate a flow of solution within the microchannel (3). The microfluidic system has at least one electrode (8) for monitoring said flow of solution by measuring an electrochemical property of said solution.

Abstract: The present invention relates to a microfluidic electrochemical sensor apparatus and a method for conducting analytical tests with said apparatus for multi-reactant assays. The apparatus of this invention is a multi-layer body made of at least three layers, the first one being a polymer layer (1) comprising a microstructure (5) with at least one integrated microelectrode (4) and conductive tracks (13) for connection to an external electrochemical unit, the second one being a non-porous material serving to cover said microstructure so as to enable microfluidic manipulations and the third one being a porous layer (2) such as a membrane or a glass frit, said porous layer comprising at least one reagent (3) to be solubilized upon contact with a test solution (7) and reacting with an analyte (6) present in said solution to form a product that is transported along said microstructure so as to enable electrochemical detection of said analyte.