# US 9,518,991 B2 · Method and apparatus for analyzing acetone in breath > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,518,991 B2 - Document ID: US9518991B2 - Status: Granted - Kind: B2 - Application number: 14/400,911 - Filed: 2013-05-15 - Published: 2015-05-14 - Granted: 2016-12-13 - Earliest claimed: 2012-05-15 - Assignees: Invoy Technologies, LLC - Applicants: Invoy Technologies, LLC - Inventors: Lubna M. Ahmad; Brent Satterfield; Rhett Martineau - Web page: https://patentgrep.com/patent/US9518991B2 ## CPC - G01N 33/64: involving ketones - A61B 5/082: {Evaluation by breath analysis, e.g. determination of the chemical composition of exhaled breath (A61B5/083, A61B5/091 take precedence)} - A61B 5/097: Devices for facilitating collection of breath or for directing breath into or through measuring devices - G01N 21/783: {for analysing gases} - G01N 33/497: of gaseous biological material, e.g. breath - A61B 5/0059: {using light, e.g. diagnosis by transillumination, diascopy, fluorescence (photoacoustic A61B5/0093; optical measurement of heart rate A61B5/02416; optical measurement of blood flow A61B5/0261; optical measurement of analytes A61B5/1455)} - A61B 2010/0087: {Breath samples} - A61B 2560/0233: Optical standards - G01N 33/4975: {other than oxygen, carbon dioxide or alcohol, e.g. organic vapours} - Y10T 436/202499: Formaldehyde or acetone - 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) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract Methods and devices are provided for analyzing acetone in breath. One such method comprises disposing a reactant in a reaction zone within the breath analysis device, wherein the reactant comprises a primary amine disposed on a surface, and wherein the reaction zone has an optical characteristic that is at a reference level. It also comprises pre-storing a liquid nitroprusside solution within the breath analysis device separately from the reactant. The method further comprises using the breath analysis device to cause the breath to contact the reactant in the reaction zone so that the acetone in the breath reacts with the reactant to form a reaction product and, after the reaction product has been formed, using the breath analysis device to cause the nitroprusside solution to contact and react with the reaction product and to facilitate a change in the optical characteristic of the reaction zone relative to the reference level. ## Claims ### Claim 1 A method for sensing acetone in breath using a breath analysis device, the method comprising: providing a breath analysis device having a reactant in a reaction zone, wherein the reactant comprises a primary amine disposed on a surface, and wherein the reaction zone has an optical characteristic that is at a reference level; a liquid nitroprusside solution disposed within the breath analysis device separately from the reactant; using the breath analysis device to cause the breath to contact the reactant in the reaction zone so that the acetone in the breath reacts with the reactant to form a reaction product; after the reaction product has been formed, using the breath analysis device to cause the nitroprusside solution to contact and react with the reaction product and to facilitate a change in the optical characteristic of the reaction zone relative to the reference level; and using the breath analysis device to detect the change in the optical characteristic to sense the acetone in the breath. ### Claim 2 (depends on 1) A method as recited in claim 1 wherein causing the nitroprusside solution to contact the reaction product has an optical characteristic that is at a second reference level, and further wherein causing the nitroprusside solution to react with the reaction product facilitates a change in the optical characteristic of the reaction zone relative to the second reference level. ### Claim 3 (depends on 1) A method as recited in claim 1, wherein the surface comprises a silica gel. ### Claim 4 (depends on 1) A method as recited in claim 1, wherein the surface comprises a plurality of silica gel beads. ### Claim 5 (depends on 4) The method as recited in claim 4, wherein the silica gel beads have a size distribution between 270 and 100 mesh. ### Claim 6 (depends on 1) A method as recited in claim 1, wherein the providing a breath analysis device having a reactant in the reaction zone step comprises providing a device in which the reactant is maintained in an alkaline environment. ### Claim 7 (depends on 1) A method as recited in claim 1, wherein the providing a breath analysis device having a reactant in the reaction zone step comprises providing a device in which the reactant is maintained in the absence of volatile acid. ### Claim 8 (depends on 1) A method as recited in claim 1, wherein the providing a breath analysis device having a reactant in the reaction zone step comprises providing a device in which the primary amine is quenched with a non-volatile acid. ### Claim 9 (depends on 1) A method as recited in claim 1, wherein the providing a breath analysis device having a reactant in the reaction zone step comprises providing a device in which the primary amine is quenched with sulfuric acid. ### Claim 10 (depends on 1) A method as recited in claim 1, wherein the liquid nitroprusside solution within the breath analysis device consists essentially of a non-alkaline solution. ### Claim 11 (depends on 1) A method as recited in claim 1, wherein the liquid nitroprusside solution does not include a substance with a base dissociation constant less than 6. ### Claim 12 (depends on 1) A method as recited in claim 1, comprising quenching the liquid nitroprusside solution so that the liquid nitroprusside solution has a pH of less than 8. ### Claim 13 (depends on 1) A method as recited in claim 1, comprising, quenching the liquid nitroprusside solution so that the liquid nitroprusside solution has a pH of less than 7. ### Claim 14 (depends on 1) A method as recited in claim 1 wherein the liquid nitroprusside solution is stored in the absence of ambient light. ### Claim 15 A method for sensing acetone in breath using a breath analysis device, the method comprising: providing a breath analysis device comprising a reactant in a reaction zone within the breath analysis device, wherein the reactant comprises a primary amine disposed on a surface, and wherein the reaction zone has an optical characteristic that is at a reference level; and a liquid nitroprusside solution in the breath analysis device in a non-alkaline environment; using the breath analysis device to cause the breath to contact the reactant in the reaction zone so that the acetone in the breath reacts with the primary amine to form a reaction product; after the reaction product has been formed, using the breath analysis device to cause the nitroprusside to contact and react with the reaction product and to facilitate a change in the optical characteristic of the reaction zone relative to the reference level; and using the breath analysis device to detect the change in the optical characteristic and to sense the acetone in the breath. ### Claim 16 (depends on 15) A method as recited in claim 15, comprising quenching the primary amine on the surface with a non-volatile acid so that the primary amine on the surface has a pH that is less than 8. ### Claim 17 (depends on 15) A method as recited in claim 15, comprising quenching the primary amine on the surface with a non-volatile acid so that the primary amine on the surface has a pH that is less than 7. ### Claim 18 (depends on 16) A method as recited in claim 16, wherein the non-volatile acid comprises sulfuric acid. ### Claim 19 (depends on 15) A method as recited in claim 15, comprising pre-storing the nitroprusside separately from the reactant prior to the causing of the nitroprusside to contact the primary amine reaction product step. ### Claim 20 (depends on 19) A method as recited in claim 19, wherein the pre-storing of the nitroprusside separately from the reactant comprises using a gas-tight barrier. ### Claim 21 (depends on 15) A method as recited in claim 15, wherein the nitroprusside solution is stored in the absence of a substance with a base dissociation constant less than 6. ### Claim 22 (depends on 15) A method as recited in claim 15, wherein the nitroprusside is quenched with a non-volatile acid. ### Claim 23 (depends on 22) A method as recited in claim 22, wherein the non-volatile acid comprises sulfuric acid. ### Claim 24 (depends on 15) A method as recited in claim 15, wherein the nitroprusside solution is quenched with a non-volatile acid so that the environment has a pH is below 8. ### Claim 25 (depends on 15) A method as recited in claim 15, wherein the nitroprusside is quenched with a non-volatile acid so that the environment has a pH is below 7. ### Claim 26 (depends on 15) A method as recited in claim 15, wherein: the surface upon which the primary amine is disposed comprises a first surface; the nitroprusside is disposed on a second surface other than the first surface; the first and second surfaces are intermingled prior to the causing of the nitroprusside to contact the reaction product; and the causing of the nitroprusside to contact and react with the reaction product comprises dispensing a liquid developer solution to contact the first and second surfaces. ### Claim 27 (depends on 15) A method as recited in claim 15, wherein: the nitroprusside is coupled to the reactant prior to the causing of the nitroprusside to contact the primary amine product; the reactant and the nitroprusside are disposed in the non-alkaline environment; and the causing of the nitroprusside to contact and react with the reaction product comprises dispensing a liquid developer solution to contact the nitroprusside and the reaction product.