Device and method for sensing the conductivity of a fluid

A method for sensing an electrolytic conductivity of a fluid, the method comprising the steps of:

• providing a battery comprising an oxidizing electrode and a reducing electrode that are separated at a distance and connected by one of a hydrophilic material, a porous material, a combination of the hydrophilic material and the porous material, or an empty receptacle, thereby providing a microfluidic cavity,
• a battery performance being sensitive to a presence of analytes with ionic charge that determine an electrolytic conductivity of the fluid to be sensed, the fluid acting as a battery electrolyte and not as fuel,
• the oxidizing electrode comprising a first material that undergoes oxidation and the reducing electrode comprising a second material that undergoes reduction, the oxidizing electrode and the reducing electrode being indirectly in contact via the fluid,
• an internal resistance of the battery depending on the electrolytic conductivity of the fluid, and
• the battery being activated upon an addition of the fluid to the microfluidic cavity;
• providing, by the battery, electrical energy while the fluid impregnates by capillarity the microfluidic cavity;
• and
• connecting at least one instrument to the battery, the instrument being designed such that its equivalent impedance makes the battery work at a specific operating point allowing determining or discriminating among values of the electrolytic conductivity of the fluid via a Direct Current (DC) mode method,
• wherein the instrument further quantifies the electrolytic conductivity of the fluid from the electrical energy provided by the battery,
• wherein the electrolytic conductivity of the fluid is inferred from the battery performance.