# US 12,111,278 B2 · Portable impedance based chemical sensor

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- Number: US 12,111,278 B2
- Document ID: US12111278B2
- Status: Granted
- Kind: B2
- Application number: 16/398,825
- Filed: 2019-04-30
- Published: 2020-08-06
- Granted: 2024-10-08
- Earliest claimed: 2019-01-31
- Assignees: The Board of Trustees of The University of Alabama; The U.S. Army, Edgewood Chemical and Biological Center
- Applicants: The Board of Trustees of the University of Alabama; The U.S. Army, Edgewood Chemical and Biological Center
- Inventors: Adam Hauser; Jennifer Rose Soliz; Smriti Ranjit
- Web page: https://patentgrep.com/patent/US12111278B2

## CPC

- G01N 27/221: {by investigating the dielectric properties (using microwaves G01N22/00; measuring loss factors or dielectric constants per se G01R27/26)}
- G01N 27/026: {Dielectric impedance spectroscopy (electrochemical impedance spectroscopy for measuring corrosion G01N17/02)}
- G01N 29/226: {Handheld or portable devices}
- G01N 33/0034: {comprising neural networks or related mathematical techniques}
- G01N 33/0036: {specially adapted to detect a particular component (physical analysis of gaseous biological material G01N33/497)}
- G01N 2027/222: {for analysing gases}
- 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 apparatus for sensing a target analyte includes a sensing material of a baseline composition. The sensing material is in electrical communication with an alternating energy input across the sensing material at a first frequency. The sensing material is configured to be placed within an environment such that an exposed state is in communication with a concentration of a target analyte proximate the sensing material, and wherein the target analyte changes at least one compositional property of the baseline composition. An impedance detection device is connected to a sensing circuit and receives an output from the sensing material, the output exhibiting a respective impedance value of the sensing material corresponding to the input for the first frequency. The respective impedance value is dependent upon the concentration of the target analyte in the environment and the first frequency.

## Claims

### Claim 1

An apparatus for sensing a target analyte, the apparatus comprising:
a sensing material comprising a baseline composition and a dopant that reacts with the target analyte, wherein the dopant corresponds to a selectivity of the sensing material for the target analyte,
wherein the sensing material comprises a metal hydroxide or a mixed metal hydroxide,
wherein the dopant is selected from the group consisting of CoCl2, CoS2, Co(NO3)2, Co(NH3)2, Co(acetate)2, CuS2, CuCl2, Cu(NO3)2, Cu(NH3)2, Cu(acetate)2, Ni(NO3)2, Ni(NH3)2, NiS2, NiCl2, FeCl3, FeS3, Fe(NO3)3, Fe(NH3)3, Ln(NO3)x (Ln=lanthanides), Ln(acetate)x, and combinations thereof;
wherein the sensing material is in electrical communication with an energy source that directs an input of either an AC voltage or an AC current across the sensing material at a first frequency, at least a portion of the sensing material positioned in an exposed state relative to an environment;
wherein the sensing material is configured to be placed within the environment such that the exposed state comprises a concentration of the target analyte proximate the sensing material, and
wherein the sensing material comprises structural features allowing a target analyte to change a composition of the sensing material by reacting with the dopant;
an impedance detection device connected to a sensing circuit and receiving an output from the sensing material, the output exhibiting a respective impedance value of the sensing material corresponding to the input for the first frequency; and
wherein the respective impedance value is dependent upon the dopant, the concentration of the target analyte in the environment and the first frequency.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein a respective structural feature of the sensing material is a thickness of the sensing material in which the dopant material is positioned to react with the target analyte, and wherein changes in the composition of the baseline composition are exhibited in the respective impedance value.

### Claim 3 (depends on 1)

The apparatus of claim 1 wherein said dopant is present at a concentration of 1 to 90 weight percent.

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein said baseline composition comprises a film.

### Claim 5 (depends on 1)

The apparatus of claim 1, wherein the energy source scans a series of AC voltage inputs or AC current inputs at respective frequencies in a frequency spectrum across the sensing material, and wherein the baseline composition of the sensor material comprises a baseline impedance profile, wherein a change in respective impedance values relative to the baseline impedance profile of the sensing material across the frequency spectrum is greater than a threshold impedance change value and indicates presence of the target analyte at the sensing material.

### Claim 6 (depends on 5)

The apparatus of claim 5, wherein the threshold impedance change value is calculated to establish a selectivity of the sensing material for the target analyte in the exposed state of the sensing material.

### Claim 7 (depends on 5)

The apparatus of claim 5, wherein the threshold impedance change value tunes the selectivity of the sensing material in the frequency domain for a concentration range of the respective target analyte.

### Claim 8 (depends on 1)

The apparatus of claim 1, further comprising wherein the sensing material with the baseline composition and the dopant is hydrophobic.

### Claim 9 (depends on 1)

The apparatus of claim 1, further comprising wherein the structural features of the sensing material with the baseline composition and the dopant comprise bond angles that correspond to the selectivity of the target analyte.

### Claim 10 (depends on 1)

The apparatus of claim 1, further comprising wherein the sensing material with the baseline composition and the dopant comprises a dielectric constant that corresponds to the selectivity of the target analyte.

### Claim 11 (depends on 10)

The apparatus of claim 10, wherein the structural features of the sensing material with the baseline composition and the dopant comprise a number of reaction sites within a thickness of the sensing material for the target analyte that determines the respective impedance value.

### Claim 12 (depends on 1)

The apparatus of claim 1, wherein the dopant comprises copper sulfide and the sensing material is hydrophobic.

### Claim 13 (depends on 1)

The apparatus of claim 1, wherein the sensing material with the baseline material and the dopant, comprises a dielectric constant that shifts in the presence of the target analyte.

### Claim 14 (depends on 1)

The apparatus of claim 1, wherein the sensing material, with the baseline material and the dopant, is a non-polar sensing material.

### Claim 15 (depends on 1)

The apparatus of claim 1, wherein the sensing material is an adsorbent material relative to the target analyte.

### Claim 16 (depends on 1)

The apparatus of claim 1, wherein the sensing material comprises graphene oxide.

### Claim 17 (depends on 1)

The apparatus of claim 1, wherein the sensing material is porous.