Device and method for sensing the conductivity of a fluid

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

• providing a battery comprising an oxidizing electrode and a reducing electrode that are separated at a distance and connected by a hydrophilic and/or a porous material or an empty receptacle, providing a microfluidic cavity,
• the battery being sensitive, only, to the presence of analytes with ionic charge that determine an electrolytic conductivity of a fluid to be sensed, the fluid acting as battery electrolyte and not as fuel,
• the oxidizing and reducing electrodes being made of a material that oxidizes and reduces itself, and being connected through the fluid,
• an internal resistance of the battery depending on the electrolytic conductivity of the fluid, and
• the battery being activated upon the 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, such that the electrolytic conductivity of the fluid is inferred from a performance of the battery.

A device for sensing the electrolytic conductivity of a fluid, comprising:

• at least one fluid-activated battery comprising an oxidizing electrode and a reducing electrode that are separated at a distance and connected by a hydrophilic and/or a porous material or an empty receptacle, providing a microfluidic cavity for a fluid, said battery being configured to provide electrical energy while the fluid impregnates by capillarity the microfluidic cavity;
• and
• at least one instrument connected to the battery;
• the battery being sensitive, only, to the presence of analytes with ionic charge that determine an electrolytic conductivity of the fluid, the fluid acting as battery electrolyte and not as a fuel;
• the oxidizing and reducing electrodes being made of a material that oxidizes and reduces itself, and being connected through the fluid;
• an internal resistance of the battery depending on the electrolytic conductivity of the fluid;
• and
• the instrument being designed such that its equivalent impedance is configured to make the battery work at a specific operating point that allows determining or discriminating among values of the electrolytic conductivity of the fluid via a Direct Current (DC) mode method, wherein the instrument is further configured for quantifying the electrolytic conductivity of the fluid, thereby inferring the electrolytic conductivity of the fluid from the performance of the battery.