Microfluidic electrochemical device for measuring a volume flow rate

A microfluidic electrochemical device (100) for measuring a volume flow rate (Q) of a fluid, the fluid comprising a solvent, the microfluidic electrochemical device (100) comprising:

• at least one microfluidic channel (11, 11a, 11b, 11c) configured to allow the fluid to flow in a flow direction (13);
• at least one electrochemical cell (14, 14a, 14b, 14c) disposed in the at least one microfluidic channel (11, 11a, 11b, 11c), the electrochemical cell (14, 14a, 14b, 14c) comprising a first working electrode (WE1) and at least one second working electrode (WE2, WE2(1), WE2(2)), with said at least one second working electrode (WE2, WE2(1), WE2(2)) being spaced apart from the first working electrode (WE1) by an inter-electrode distance (La, Lb, Lc, L(1), L(2)) in the flow direction (13), at least one counter-electrode (CE) and at least one reference electrode (REF);
• an electrochemical amperometry measurement system (15) configured to bias the first working electrode (WE1) at a first electrode potential (E1) and the second working electrode (WE2, WE2(1), WE2(2)) at a second electrode potential (E2), so that each of said first and second working electrodes produces an amperometric signal by oxidation reaction or by reduction reaction of the solvent or with at least one chemical species forming a redox couple with the solvent;
• and
• the electrochemical amperometry measurement system (15) being configured to determine the volume flow rate (Q) of the fluid in the microfluidic channel (11, 11a, 11b, 11c) based on the inter-electrode distance (La, Lb, Lc, L(1), L(2)) and a time delay (Δt) between a variation in the amperometric signal produced by the first working electrode (WE1) and a variation in the amperometric signal produced by the second working electrode (WE2, WE2(1), WE2(2)).