Sensor for detection of gas such as hydrogen and method of fabrication

• US 7,897,057 B1
• Filed: 02/28/2007
• Issued: 03/01/2011
• Est. Priority Date: 09/04/2001
• Status: Expired due to Fees

• Current Assignee: Optech Ventures, LLC
• Original Assignee: Optech Ventures, LLC
• Inventors: Goswam, Kisholoy, O'Connor, Paul B.
• Primary Examiner(s): Alanko; Anita K
• Application Number:
  US11/680,546
• Time in Patent Office: 1,462 Days
• Field of Search: 216/57
• US Class Current: 216/24
• CPC Class Codes: C03C 15/00 Surface treatment of glass, not in the form of fibres or filaments, by etching etching or surface-brightening compositions, in general C09K13/00
• CPC Class Codes: G01N 21/7703 using reagent-clad optical fibres or optical waveguides using measurement of total internal reflection or attenuated total reflection G01N21/552; optical fibres or waveguides per se G02B
• CPC Class Codes: G01N 21/783 for analysing gases

Abstract

A gas sensor system and its method of fabrication is disclosed. The sensor system comprises an optrode, light source, and a light detector. In a sensor for hydrogen gas, the optrode is comprised of a porous substrate into which an intimate mixture of reagent and catalyst is incorporated. The mixture reacts with the hydrogen to produce a color/intensity change in relation to the concentration of gas. The optrode further includes a reversing agent, boron, to restore the benchmark conditions of the sensor system in real-time. The method of fabricating the optrode includes the steps of cleaning; etching to achieve the proper porosity; incorporating the reagent, catalyst, and reversing agent using capillary action; and removing excess reagent and catalyst.

Claims

1. A process of manufacturing an optrode for detecting a has, comprising the steps of:

selecting a substrate that is substantially transparent to one or more input wavelengths the substrate including a plurality of interconnected pores;

preparing the substrate to receive an indicator solution;

producing an indicator solution that will optically change in relation to the concentration of gas comprising;

(i) adding a source of reagent;

(ii) adding a source of catalyst;

(iii) adding boron; and

incorporating the indicator solution into the pores of the substrate.

2. A process of manufacturing an optrode for detecting a gas, the method comprising the steps of:

(a) selecting a porous substrate that is substantially transparent to visible light;

the substrate including a plurality of interconnected pores;

(b) preparing the substrate, comprising the steps of;

(i) cleaning the substrate with hydrogen peroxide; and

(ii) etching the substrate with ammonium fluoride solution;

(c) producing an indicator solution, comprising the steps of;

(i) adding a source of reagent;

(ii) adding a source of catalyst;

(iii) adding a boron containing reversing agent; and

(iv) adding a molecular barrier;

(d) incorporating the indicator solution into the pores of the substrate, comprising the steps of;

(i) placing the substrate in contact with the indicator solution to draw the indicator solution into the pores of the substrate;

(ii) drying the substrate;

whereby indicator material is deposited into the pores of the substrate; and

(e) removing loosely-bound indicator material with organic solvent.