# US 2020/0400596 A1 · Device and method for sensing the conductivity of a fluid

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- Number: US 2020/0400596 A1
- Document ID: US20200400596A1
- Status: Published application
- Kind: A1
- Application number: 16/979,114
- Filed: 2019-03-11
- Published: 2020-12-24
- Earliest claimed: 2018-03-12
- Assignees: Consejo Superior de Investigaciones Cientificas; Institució Catalana De Recerca I Estudis AvançAts (Icrea)
- Applicants: Consejo Superior De Investigaciones CientíFicas; Institució Catalana De Recerca I Estudis AvançAts
- Inventors: Laura ORTEGA TAÑÁ; Anna LLORELLA BUSTINS; Juan Pablo ESQUIVEL BOJORQUEZ; Neus SABATÉ VIZCARRA
- Web page: https://patentgrep.com/patent/US20200400596A1

## CPC

- G01N 27/06: of a liquid (involving electrolysis G01N27/26)
- G01N 27/07: Construction of measuring vessels; Electrodes therefor
- G01R 31/389: Measuring internal impedance, internal conductance or related variables
- H01M 6/32: activated through external addition of electrolyte or of electrolyte components
- H01M 10/484: {for measuring electrolyte level, electrolyte density or electrolyte conductivity}
- Y02E 60/50: Fuel cells
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A device and a method for sensing the electrolytic conductivity of a fluid are disclosed. The device comprises a battery (1) having an oxidizing electrode (2) and a reducing electrode (3) connected by a hydrophilic and/or a porous material or an empty receptacle (4) providing a microfluidic cavity for a fluid (10), said battery (1) being activated upon the addition of said fluid (10) therein and providing electrical energy while the fluid (10) impregnates by capillarity said microfluidic cavity; and at least one instrument (5) connected to the battery (1). The instrument (5) has an equivalent impedance that makes the battery (1) work at a specific operating point allowing determining or discriminating among values of electrolytic conductivity of the fluid (10) and includes means for quantifying the electrolytic conductivity of the fluid (10), thereby inferring the conductivity of the fluid (10) from the performance of the battery (1).

## Claims

### Claim at position 1

-13. (canceled)

### Claim 14

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.

### Claim 15 (depends on 14)

The method of claim 14, further comprising adjusting a battery response by:
adding one or more chemical species to the battery, before or after the fluid is added to the battery, to shift the electrolytic conductivity range in which the battery operates; or
adding salts before or after the fluid is added to the battery to increase the electrolytic conductivity of the fluid to achieve a selected sensitivity range; or
adding an enzyme, bacteria or inorganic catalyst to the fluid before its addition to the battery or to the hydrophilic and/or porous material or empty receptacle in order the enzyme or metal catalyst reacting with a particular substance present in the fluid causing a change in the electrolytic conductivity;
adding a given amount of titrant to the hydrophilic and/or porous material or an empty receptacle to determine a specific ion or molecule concentration of the fluid; or
adding and ion-selective membrane.

### Claim 16

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.

### Claim 17 (depends on 16)

The device of claim 16, wherein the battery is a paper-based battery.

### Claim 18 (depends on 16)

The device of claim 16, wherein the fluid is a water-based fluid comprising plain water, river water, a beverage including juice or milk, an ink or a biological fluid including saliva, urine, blood, sperm, plasma, serum, mucus, tears, feces or sweat, or a non-aqueous liquid including an ionic liquid.

### Claim 19 (depends on 16)

The device of claim 16, wherein the instrument further comprises one or more electronic modules configured to perform power management functions, signal control and processing functions of an electrical signal captured from the battery or telecommunication functions.

### Claim 20 (depends on 19)

The device of claim 19, wherein the instrument further comprises at least one of: a memory to store a result of said quantification, a communication unit to transmit said result to an external device, an indicator comprising an audible and/or a visual indicator including a buzzer, a screen, a display or an alarm to indicate the result.

### Claim 21 (depends on 16)

The device of claim 16, wherein the instrument is configured to be solely powered by an amount of electrical energy provided by the battery or is configured to be solely powered by an external power source or by an amount of electrical energy provided by the battery and amount of energy from an external power source.

### Claim 22 (depends on 16)

The device of claim 16, wherein the oxidizing electrode and the reducing electrode of the battery are arranged side by side, face to face or in an interdigitated configuration.

### Claim 23 (depends on 16)

The device of claim 16, further comprising several batteries connected in series to increase an output voltage or in parallel to increase an output current.

### Claim 24 (depends on 16)

The device of claim 16, wherein the hydrophilic and/or porous material or empty receptacle comprises an enzyme, bacteria or inorganic catalyst configured to react with a particular substance present in the fluid that causes a change in the electrolytic conductivity of the fluid.

### Claim 25 (depends on 16)

The device of claim 16, further comprising an ion selective membrane.