Method of making a gas sensor

• US 4,867,919 A
• Filed: 01/26/1989
• Issued: 09/19/1989
• Est. Priority Date: 10/10/1986
• Status: Expired due to Term

• Current Assignee: Terumo Cardiovascular Systems Corporation (Terumo Corporation)
• Original Assignee: 3M Company
• Inventors: Yafuso, Masao, Suzuki, John K.
• Primary Examiner(s): Thurlow, Jeffery
• Assistant Examiner(s): Tentoni, Leo B.
• Application Number:
  US07/302,832
• Time in Patent Office: 236 Days
• Field of Search: 264/1.1, 264/1.5, 264/1.7, 264/78, 264/204, 264/236, 264/347, 8/541, 8/543, 8/599, 8/618, 8/648, 128/634, 250/227, 356/39, 422/58, 422/83, 436/68, 436/133, 436/172, 524/424
• US Class Current: 264/78
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• CPC Class Codes: G01N 2021/6434 Optrodes
• CPC Class Codes: G01N 21/643 non-biological material
• CPC Class Codes: G01N 21/81 Indicating humidity
• CPC Class Codes: G01N 31/223 for investigating presence of specific gases or aerosols G01N31/221, G01N31/222 take precedence; actuation of fire alarm by presence of smoke or gases G08B17/10

Abstract

A method for preparing a gas sensor includes forming a mixture containing an aqueous buffer solution including a dissolved dye, a polymeric precursor of a cross-linked polymeric material, and a cross-linking agent and reacting the polymeric precursor and the cross-linking agent in the mixture to form a gas sensor including micro-compartments of the aqueous buffer solution dispersed in the cross-linked polymeric material.

Claims

1. A method for preparing a gas sensor comprising:

forming a mixture containing an aqueous buffer solution including a dissolved dye, a polymeric precursor of a cross-linked polymeric material, and a cross-linking agent; and

reacting said polymeric precursor and said cross-linking agent in said mixture to form a gas sensor comprising micro-compartments of said aqueous buffer solution dispersed in said cross-linked polymeric material.

2. The method of claim 1 wherein said mixture is an emulsion.

3. The method of claim 1 wherein said aqueous buffer solution further includes an emulsification enhancement agent.

4. The method of claim 1 wherein said cross-linked polymeric material is gas and light permeable, and substantially ion and aqueous impermeable.

5. The method of claim 1 wherein said dye is present in said aqueous buffer solution in a concentration in the range of about 2 millimolar to about 50 millimolar.

6. The method of claim 1 wherein said aqueous buffer solution includes a buffer present in a concentration in the range of about 2 millimolar to about 50 millimolar.

7. The method of claim 1 wherein said mixture includes about 1 gram to about 4 grams of said aqueous buffer solution per 10 grams of said polymeric precursor.

8. The method of claim 1 wherein said mixture includes about 0.5 grams to about 2 grams of said cross-linking agent per 10 grams of said polymeric precursor.

9. The method of claim 1 wherein said mixture further includes a catalyst effective to promote said reaction.

10. The method of claim 3 herein said emulsification enhancement agent is present in an amount in the range of about 10% to about 30% by weight of said aqueous buffer solution.

11. The method of claim 1 wherein said dye is a pH sensitive dye.

12. The method of claim 1 wherein said aqueous buffer solution is a bicarbonate ion based buffer solution.

13. The method of claim 1 wherein said gas sensor is a carbon dioxide sensor.

14. The method of claim 1 wherein said dye is hydroxypyrene 3, 6, 8-trisulfonic acid or a salt thereof.

15. The method of claim 1 wherein said micro-compartments are smaller than 5 microns.

16. The method of claim 1 wherein said dye is present in said mixture in an amount of about 0.01 grams per 2 mls. of said aqueous buffer solution, said aqueous buffer solution is present in said mixture in an amount of about 2 mls. per 10 grams of said polymeric precursor, and said cross-linking agent is present in said mixture in an amount of about 1 gram per 10 grams of said polymeric precursor.

17. The method of claim 16 wherein said aqueous buffer solution further includes about 0.66 grams of an emulsification enhancement agent per 2 mls of said aqueous buffer solution.

18. The method of claim 1 which further comprises placing said mixture on the end of an optic fiber prior to said reacting step.

19. A method for preparing a carbon dioxide sensor comprising:

forming a mixture containing an aqueous buffer solution including a dissolved pH sensitive dye, a polymeric precursor of a cross-linked, light and gas permeable, substantially ion and aqueous impermeable polymeric material, a cross-linking agent and a catalyst; and

reacting said polymeric precursor and said cross-linking agent in said mixture to form a carbon dioxide sensor comprising micro-compartments of said aqueous buffer solution dispersed in said cross-linked polymeric material.

20. The method of claim 19 which further comprises placing said mixture on the end of an optical fiber prior to said reacting step.