# US 7,608,180 B2 · Amperometric sensor

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 7,608,180 B2
- Document ID: US7608180B2
- Status: Granted
- Kind: B2
- Application number: 11/312,486
- Filed: 2005-12-21
- Published: 2006-05-11
- Granted: 2009-10-27
- Earliest claimed: 1999-06-29
- Assignees: Drew Scientific Holdings, Inc.
- Inventors: Kim King Tong Lau; Jonathan Mark Slater
- Web page: https://patentgrep.com/patent/US7608180B2

## CPC

- C01C 3/12: Simple or complex iron cyanides
- C01B 15/01: Hydrogen peroxide
- C07C 211/63: having quaternised nitrogen atoms bound to acyclic carbon atoms
- C12Q 1/004: {mediator-assisted}
- C12Q 1/006: {for glucose}
- G01N 27/3271: {Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood (amperometry per se G01N27/49; aspects concerning the enzyme reagent C12Q1/001)}
- C01C: AMMONIA; CYANOGEN; COMPOUNDS THEREOF ({metal hydrides, monoborane, diborane or addition complexes thereof C01B6/00}; salts of oxyacids of halogens C01B11/00; peroxides, salts of peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium or tellurium C01B19/00; azides C01B21/08; {compounds other than ammonia or cyanogen, containing nitrogen, non-metals and optionally metals C01B21/082}; metal imides or amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; compounds containing silicon C01B33/00; compounds containing boron C01B35/00)
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C12Q: MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS (immunoassay G01N33/53); COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES
- 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 amperometric sensor suitable for determining the concentration of hydrogen peroxide in a sample, the sensor comprising a ferricyanide compound which, in reduced form, functions as a mediator specific to hydrogen peroxide.

## Claims

### Claim 1

A method for determining the concentration of H2O2 in a sample containing H2O2, which method comprises:
providing a sensor comprising 2 or 3 electrodes, one of the electrodes being coated with a ferricyanide compound which in reduced form functions as a mediator selective for hydrogen peroxide, wherein the ferricyanide compound has a low solubility in an aqueous phase,
applying a potential of about −400 mV to the sensor, such that the oxidised form of the mediator is reduced to the reduced form,
contacting the sensor with the sample, such that the H2O2 oxidises the reduced form of the mediator to the oxidised form,
maintaining the applied potential of about −400 mV such that the oxidised form of the mediator generating a current,
measuring the generated current.

### Claim 2 (depends on 1)

A method according to claim 1, wherein the ferricyanide compound is of general formula:
X3Fe(CN)6
in which the groups X are the same or different and at least one X is a non-metallic ion.

### Claim 3 (depends on 2)

A method according to claim 2, in which each X is a quaternary ammonium ion of formula (R1) (R2) (R3) (R4) N+ in which R1 to R4 are the same or different alkyl groups containing from 1 to 20 carbon atoms, provided that at least one of R1 to R4 contains at least 4 carbon atoms.

### Claim 4 (depends on 3)

A method according to claim 3, wherein the ferricyanide compound is tetrahexylammonium ferricyanide, tetrakisdecylammonium ferricyanide, tetradecyltrimethylammonium ferricyanide, hexadecyltrimethylammonium ferricyanide or trimethylhexylammonium ferricyanide.

### Claim 5 (depends on 2)

A method according to claim 2, wherein each X is a nitrogen-containing heterocyclic cation.

### Claim 6 (depends on 5)

A method according to claim 5, wherein each X is a pyridinium ion.

### Claim 7 (depends on 2)

A method according to claim 2, wherein each X is a phosphonium ion of formula (R5) (R6) (R7) (R8) P+ in which R5 to R8 are the same or different alkyl groups containing from 1 to 20 carbon atoms, provided that at least one group R5 to R8 contains at least 4 carbon atoms.

### Claim 8 (depends on 1)

A method according to claim 1, in which the ferricyanide compound is bound to a polymer.

### Claim 9 (depends on 8)

A method according to claim 8, wherein the polymer is a polyacrylamide.

### Claim 10 (depends on 8)

A method according to claim 8, wherein the ferricyanide compound is bound to the polymer via one of groups R1 to R4 of a quaternary ammonium ion of formula
(R1)(R2)(R3)(R4)N+
or via one of groups R5 to R8 of a quaternary phosphonium ion of formula
(R5)(R6)(R7)(R8)P+
or via a nitrogen-containing heterocyclic cation.

### Claim 11 (depends on 8)

A method according to claim 8, wherein the ferricyanide compound is polypyridinium ammonium ferricyanide or poly(acrylamide-co-diethyldimethyl ammonium)ferricyanide.

### Claim 12 (depends on 1)

A method according to claim 1, wherein the solubility of the ferricyanide compound in water is from 2,000 to 20,000 mg/l.

### Claim 13

A method for determining the concentration of an analyte in a sample, which analyte is capable of producing H2O2 when contacted with an analyte, the method comprising:
contacting the sample with an enzyme such that the analyte in the sample reacts with the enzyme to produce H2O2
providing a sensor comprising 2 or 3 electrodes, one of the electrodes being coated with a ferricyanide compound which in reduced form functions as a mediator selective for hydrogen peroxide, wherein the ferricyanide compound has a low solubility in an aqueous phase,
applying a potential of about −400 mV to the sensor, such that the oxidised form of the mediator is reduced to the reduced form,
contacting the sensor with the sample, such that the H2O2 oxidises the reduced form of the mediator to the oxidised form,
maintaining the applied potential of about −400 mV such that the oxidised form of the mediator generating a current,
measuring the generated current.

### Claim 14 (depends on 13)

A method according to claim 13, wherein the enzyme is provided on an electrode.

### Claim 15 (depends on 13)

A method according to claim 13, wherein the analyte is glucose and the enzyme is glucose oxidase.

### Claim 16 (depends on 13)

A method according to claim 13, wherein the ferricyanide compound is of general formula:
X3Fe(CN)6
in which the groups X are the same or different and at least one X is a non-metallic ion.

### Claim 17 (depends on 16)

A method according to claim 16, in which each X is a quaternary ammonium ion of formula (R1) (R2) (R3) (R4) N+ in which R1 to R4 are the same or different alkyl groups containing from 1 to 20 carbon atoms, provided that at least one of R1 to R4 contains at least 4 carbon atoms.

### Claim 18 (depends on 17)

A method according to claim 17, wherein the ferricyanide compound is tetrahexylammonium ferricyanide, tetrakisdecylammonium ferricyanide, tetradecyltrimethylammonium ferricyanide, hexadecyltrimethylammonium ferricyanide or trimethylhexylammonium ferricyanide.

### Claim 19 (depends on 16)

A method according to claim 16, wherein each X is a nitrogen-containing heterocyclic cation.

### Claim 20 (depends on 19)

A method according to claim 19, wherein each X is a pyridinium ion.

### Claim 21 (depends on 16)

A method according to claim 16, wherein each X is a phosphonium ion of formula (R5) (R6) (R7) (R8) P+ in which R5 to R8 are the same or different alkyl groups containing from 1 to 20 carbon atoms, provided that at least one group R5 to R8 contains at least 4 carbon atoms.

### Claim 22 (depends on 13)

A method according to claim 13, in which the ferricyanide compound is bound to a polymer.

### Claim 23 (depends on 22)

A method according to claim 22, wherein the polymer is a polyacrylamide.

### Claim 24 (depends on 22)

A method according to claim 22, wherein the ferricyanide compound is bound to the polymer via one of groups R1 to R4 of a quaternary ammonium ion of formula
(R1)(R2)(R3)(R4)N+
or via one of groups R5 to R8 of a quaternary phosphonium ion of formula
(R5)(R6)(R7)(R8)P+
or via a nitrogen-containing heterocyclic cation.

### Claim 25 (depends on 22)

A method according to claim 22, wherein the ferricyanide compound is polypyridinium ammonium ferricyanide or poly(acrylamide-co-diethyldimethyl ammonium)ferricyanide.

### Claim 26 (depends on 13)

A method according to claim 13, wherein the solubility of the ferricyanide compound in water is from 2,000 to 20,000 mg/l.