Method and arrangement of measuring acidity for other chemical or physical property of a gas

• US 20080227215A1
• Filed: 03/07/2008
• Published: 09/18/2008
• Est. Priority Date: 03/16/2007
• Status: Active Grant

• Current Assignee: Janesko Oy
• Original Assignee: Janesko Oy
• Inventors: Voipio, Ville, Vuokila, Katri
• Granted Patent: US 8,182,748 B2
• Time in Patent Office: Days
• US Class Current: 436/164
• CPC Class Codes: G01N 21/783 for analysing gases
• CPC Class Codes: G01N 21/80 Indicating pH value

Abstract

A method and an arrangement of measuring acidity or other chemical or physical property of a gas. The invention comprises a membrane having optical indicator molecules bound to a microporous matrix arranged to be placed into contact with the gas to be measured, the optical indicator molecules changing their colour in response to the acidity or other chemical or physical property of the gas, a light source, and a detector. The light source is arranged to emit and direct light to the membrane, the light being transmitted through the membrane, whereby a part of the light is absorbed into the optical indicator molecules, and the rest of the light emitted is guided to the detector, where it is measured.

Claims

1. Method of measuring acidity or other chemical or physical property of a gas, the method comprising the following steps,

arranging a membrane having optical indicator molecules bound to a microporous matrix is placed into contact with the gas to be measured, the optical indicator molecules changing their colour in response to the acidity or other chemical or physical property of the gas, and

directing light to the membrane, whereby a part of the light is absorbed into the optical indicator molecules, and measuring the light passed through the membrane.

2. The method according to claim 1, wherein monochromatic light is used.

3. The method according to claim 1, wherein light having more than one wave lengths are used.

4. Arrangement at measurement of acidity or other chemical or physical property of a gas, the arrangement comprising,

a membrane having optical indicator molecules bound to a microporous matrix arranged to be placed into contact with the gas to be measured, the optical indicator molecules changing their colour in response to the acidity or other chemical or physical property of the gas,

a light source, and

a detector,

the light source being arranged to emit and direct light to the membrane, the light being transmitted through the membrane, whereby a part of the light is absorbed into the optical indicator molecules, and the rest of the light emitted is guided to the detector, where it is measured.

5. The arrangement according to claim 4, wherein the light source is arranged to emit monochromatic light.

6. The arrangement according to claim 4, wherein the light source is arranged to emit more than one wavelength.

7. The arrangement according to claim 4, wherein the membrane having optical indicator molecules bound to the microporous matrix is a dye film deposited on a substrate.

8. The arrangement according to claim 7, wherein the membrane having optical indicator molecules bound to microporous matrix is a dye film fabricated by the Sol-Gel method.

9. The arrangement according to claim 7, wherein the dye film deposited on the substrate is covered by a porous mirror formed by at least one layer allowing ions to pass through and reflecting light backwards to the detector.

10. The arrangement according to claim 9, wherein the porous mirror is a dielectric mirror.