# US 2021/0333231 A1 · pH MEASUREMENT OF AN AQUEOUS SAMPLE

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- Number: US 2021/0333231 A1
- Document ID: US20210333231A1
- Status: Published application
- Kind: A1
- Application number: 16/860,715
- Filed: 2020-04-28
- Published: 2021-10-28
- Earliest claimed: 2020-04-28
- Assignees: Hach Lange GmbH; University of Warwick
- Applicants: Hach Lange GmbH; University of Warwick
- Inventors: Zoë Duncan; Mark Edward Newton
- Web page: https://patentgrep.com/patent/US20210333231A1

## CPC

- G01N 27/302: {pH sensitive, e.g. quinhydron, antimony or hydrogen electrodes (ion selective electrodes G01N27/333, glass electrodes G01N27/36)}
- G01N 27/308: {at least partially made of carbon}
- G01N 27/4167: {pH (electrodes therefor G01N27/302, G01N27/36)}
- G01N 33/18: Water
- G01N 33/1886: {using probes, e.g. submersible probes, buoys}
- G01N 27/4168: {Oxidation-reduction potential, e.g. for chlorination of water (water analysis G01N33/18)}
- 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)

## Abstract

An embodiment provides a device for measuring pH in an aqueous sample, including: a primary electrode comprising a boron doped diamond-based electrode and a primary carbon region comprising a pH sensitive sp2 carbon region, wherein the primary carbon region comprises a portion of the surface area of a face of the primary electrode; a secondary electrode comprising a boron doped diamond-based electrode and a secondary carbon region, wherein the secondary carbon region comprises a portion of the surface area of a face of the secondary electrode, the portion of the surface area of a face of the secondary electrode being less than the portion of the surface area of a face of the primary electrode; at least one reference electrode; at least one auxiliary electrode; and a memory storing instructions executable by a processor to identify a pH of an aqueous sample by measuring an electrical potential between the at least one reference electrode and at least one of: the primary electrode and the secondary electrode. Other aspects are described and claimed.

## Claims

### Claim 1

A device for measuring pH in an aqueous sample, comprising:
a primary electrode comprising a boron doped diamond-based electrode and a primary carbon region comprising a pH sensitive sp2 carbon region, wherein the primary carbon region comprises a portion of the surface area of a face of the primary electrode;
a secondary electrode comprising a boron doped diamond-based electrode and a secondary carbon region, wherein the secondary carbon region comprises a portion of the surface area of a face of the secondary electrode, the portion of the surface area of a face of the secondary electrode being less than the portion of the surface area of a face of the primary electrode;
at least one reference electrode;
at least one auxiliary electrode; and
a memory storing instructions executable by a processor to identify a pH of an aqueous sample by measuring an electrical potential between the at least one reference electrode and at least one of: the primary electrode and the secondary electrode.

### Claim 2 (depends on 1)

The device of claim 1, wherein the primary carbon region comprises a plurality of pH sensitive carbon regions.

### Claim 3 (depends on 1)

The device of claim 1, wherein the portion of the surface area of a face of the secondary electrode is zero.

### Claim 4 (depends on 1)

The device of claim 1, wherein each of the primary carbon region and the secondary carbon region is a laser micromachined area.

### Claim 5 (depends on 1)

The device of claim 1, wherein each of the primary carbon region and the secondary carbon region comprises oxidized carbon structures.

### Claim 6 (depends on 5)

The device of claim 5, wherein the oxidized carbon structures further comprise quinone-like groups.

### Claim 7 (depends on 1)

The device of claim 1, wherein the measured electrical potential between the at least one reference electrode and the primary electrode corresponds to a pH value.

### Claim 8 (depends on 1)

The device of claim 1, wherein the measured electrical potential between the at least one reference electrode and the secondary electrode corresponds to an electrochemical signal comprising an interference signal.

### Claim 9 (depends on 1)

The device of claim 1, wherein the identification of the pH value is determined by subtracting a potential from the secondary electrode from a potential from the primary electrode.

### Claim 10 (depends on 1)

The device of claim 1, wherein the aqueous sample comprises a heavy metal.

### Claim 11

A method for measuring pH in an aqueous sample with a carbon region electrode, comprising:
introducing an aqueous sample into a measurement device, wherein the measurement device comprises:
a primary electrode comprising a boron doped diamond-based electrode and a primary carbon region with a primary carbon region surface area, wherein the primary carbon region comprises a pH sensitive sp2 carbon region;
a secondary electrode comprising a boron doped diamond-based electrode and a secondary carbon region with a secondary carbon region surface area less than the primary carbon region surface area;
at least one reference electrode;
at least one auxiliary electrode; and
identifying a pH of an aqueous sample by measuring an electrical potential between the at least one reference electrode and at least one of: the primary electrode and the secondary electrode.

### Claim 12 (depends on 11)

The method of claim 11, wherein the primary carbon region comprises a plurality of pH sensitive carbon regions.

### Claim 13 (depends on 11)

The method of claim 11, wherein the portion of the surface area of a face of the secondary electrode is zero.

### Claim 14 (depends on 11)

The method of claim 11, wherein each of the primary carbon region and the secondary carbon region is a laser micromachined area.

### Claim 15 (depends on 11)

The method of claim 11, wherein each of the primary carbon region and the secondary carbon region comprises oxidized carbon structures.

### Claim 16 (depends on 15)

The method of claim 15, wherein the oxidized carbon structures further comprise quinone-like groups.

### Claim 17 (depends on 11)

The method of claim 11, wherein the measured electrical potential between the at least one reference electrode and the primary electrode corresponds to a pH value.

### Claim 18 (depends on 11)

The method of claim 11, wherein the measured electrical potential between the at least one reference electrode and the secondary electrode corresponds to an electrochemical signal comprising an interference signal.

### Claim 19 (depends on 11)

The method of claim 11, wherein the identification of the pH value is determined by subtracting a potential from the secondary electrode from a potential from the primary electrode.

### Claim 20

A system for measuring pH in an aqueous sample, comprising:
a storage device having code stored therewith, the code being executable by the processor and comprising:
code that introduces an aqueous sample into a measurement device, wherein the measurement device comprises:
a primary electrode comprising a boron doped diamond-based electrode and a primary carbon region with a primary carbon region surface area, wherein the primary carbon region comprises a pH sensitive sp2 carbon region;
a secondary electrode comprising a boron doped diamond-based electrode and a secondary carbon region with a secondary carbon region surface area less than the primary carbon region surface area;
at least one reference electrode;
at least one auxiliary electrode; and
code that identifies a pH of an aqueous sample by measuring an electrical potential between the at least one reference electrode and at least one of: the primary electrode and the secondary electrode.