Method and arrangement for measuring the concentration of gases

Abstract

A method and an arrangement for measuring the concentration of gases in a sample includes the generation of a monochromatic light beam having predetermined color characteristic. An indicator generates light signals indicative of the concentration of the gases in a sample to be measured and includes a light-transmissive surface positioned to be impinged by the monochromatic light beam, a diffusion membrane adapted to be placed in the proximity of a sample and being permeable to a selected gas component thereof, and an indicating substance positioned to be impinged by the monochromatic light beam penetrating the light-transmissive surface and by the gas component penetrating the diffusion membrane. The indicating substance reacts when illuminated by the incident monochromatic light by emitting a resultant light beam having an emitted component which has a color characteristic different from the predetermined color characteristic of the monochromatic light beam. The resultant light beam is conducted away from the indicating substance through the light-transmissive surface. Finally, the emitted component is discriminated from the resultant light beam so that the change in the color characteristic of the indicating substance can be measured and correlated with the concentration of gases in the sample.

We claim: .[.1. A method of measuring the concentration of gases in a sample comprising the steps of generating a monochromatic light beam having a predetermined color characteristic; generating light signals indicative of the concentration of gases in a sample to be measured by positioning an indicator having a light-transmissive surface positioned to be impinged by said monochromatic light beam, a diffusion membrane adapted to be placed in the proximity of a sample and being selectively permeable to a gas component thereof, and an indicating substance positioned to be impinged by the monochromatic light beam penetrating said light-transmissive surface and by said gas component penetrating said diffusion membrane, said indicating substance reacting when illuminated by said incident monochromatic light beam by emitting a resultant light beam having an emitted component which has a color characteristic different from said predetermined color characteristic; conducting said resultant light beam away from said indicating substance through said light-transmissive surface; and discriminating said emitted component from said resultant light beam so that the change in the color characteristic of said indicating substance can be measured and correlated with the concentration of gases in the sample..]. .[.2. In an arrangement for measuring the concentration of gases in a sample, a combination comprising means for generating a monochromatic light beam having a predetermined color characteristic; indicating means for generating light signals indicative of the concentration of gases in a sample to be measured, including a light-transmissive surface positioned to be impinged by said monochromatic light beam, a diffusion membrane adapted to be placed in proximity of a sample and being permeable to a selected gas component thereof, and an indicating substance positioned to be impinged by said monochromatic light beam penetrating said light-transmissive surface and by said gas component penetrating said diffusion membrane, said indicating substance reacting when illuminated by said incident monocrhomatic light beam by emitting a resultant light beam having an emitted component which has a color characteristic different from said predetermined color characteristic; means for conducting said resultant light beam away from said indicating substance through said light-transmissive surface; and means for discriminating said emitted component from said resultant light beam so that the change in the color characteristic of said indicating substance can be measured and correlated with the concentration of gases in the sample..]. .[.3. The arrangement of claim 2, wherein said indicating substance is sealingly embedded throughout said diffusion 
     
        membrane..]. 4. The arrangement of claim .[.2.]. .Iadd.33.Iaddend.; and further comprising means for controlling the temperature of a sample. .[.5. The arrangement of claim 2, wherein the indicating substance is 
     
     
        β-methyl-umbelliferon..]. 6. The arrangement of claim .[.2.]. .Iadd.33.Iaddend., wherein the indicating substance is Pyrene-butyric 
     
     
        acid. 7. The arrangement of claim .[.2.]. .Iadd.33.Iaddend.; and further comprising additional indicating substances intermixed with said first-mentioned indicating substance. .[.8. The arrangement of claim 2; and further comprising a reflecting wall located behind said membrane..]. .[.9. The arrangement of claim 2; and further comprising an absorption 
     
     
        wall located behind said membrane..]. 10. The arrangement of claim .[.2.]. .Iadd.33.Iaddend., wherein sid discriminating means comprises filtering means for permitting substantially only said emitted light to pass 
     
     
        through. 11. The arrangement of claim .[.2.]. .Iadd.33.Iaddend., wherein said indicating means is comprised of a plurality of particles, each 
     
     
        comprising said indicating substance and said diffusion membrane. 12. The arrangement of claim .[.2.]. .Iadd.33.Iaddend.; and further comprising additional indicating means adjacent said first-mentioned indicating means, said additional indicating means having a diffusion membrane selectively permeable to another gas component and an indicating substance 
     
     
        which reacts with the latter. 13. The arrangement of claim 12, wherein the diffusion membrane of said first-mentioned indicating means is substantially permeable to oxygen; and wherein the diffusion membrane of said additional indicating means is substantially permeable to 
     
     
        carbondioxide. 14. The arrangement of claim .[.2.]. .Iadd.33.Iaddend.; wherein said means for generating said monochromatic light beam includes a light-conductive cable for directing said monochromatic light beam towards said indicating means; and wherein said conducting means comprises another light-conductive cable for directing said resultant light beam away from 
     
     
        said indicating means. 15. The arrangement of claim 14; and further comprising additional indicating means located adjacent said first-mentioned indicating means; and wherein said monochromatic light beam comprises two monochromatic components, each being directed by said 
     
     
        one light-conductive cable towards said respective indicating means. 16. The arrangement of claim 15, and wherein both said indicating means respectively emit emitted light components, each being conducted by said other light-conductive cable towards said discrimination means so that 
     
     
        each emitted light component is individually measured. 17. The arrangement of claim .[.2.]. .Iadd.33.Iaddend.; and further comprising a portable housing containing said means for generating a monochromatic light beam and said discrimination means for transporting the measuring arrangement 
     
     
        to a sample. 18. The arrangement of claim 17, wherein said indicating 
     
     
        means is interchangeably mounted in said housing. 19. The arrangement of claim 17; and further comprising additional measuring electrodes mounted 
     
     
        in said housing. 20. The arrangement of claim .[.2.]. .Iadd.34.Iaddend., wherein said light-transmissive surface is planar and constitutes an upper layer, and wherein said indicating substance is generally located in a 
     
     
        plane intermediate said upper layer and said diffusion membrane. 21. The arrangement of claim .[.20.]. .Iadd.34.Iaddend., wherein said indicating substance is arranged in a dichroic layer having one side which absorbs said monochromatic light beam. .[.22. The arrangement of claim 20, wherein said membrane has a reflective layer on its side facing said indicating substance..]. .[.23. The arrangement of claim 20 wherein said membrane has 
     
     
        an absorbing layer on its side facing said indicating substance..]. 24. The arrangement of claim .[.2.]. .Iadd.33.Iaddend., wherein said means for generating a monochromatic light beam includes means for modifying the latter into a plurality of separate monochromatic components, each monochromatic component being directed towards said indicating substance. 
     
     
         5. The arrangement of claim 24, wherein said modifying means comprises a plurality of monochromatic filters, each positioned to be impinged by said 
     
     
        monochromatic light beam. 26. The arrangement of claim 24, wherein said conducting means comprises a plurality of light-reflective elements, each 
     
     
        positioned to be impinged by said emitted light component. 27. The arrangement of claim 26, wherein said discriminating means processes each 
     
     
        of said emitted light components. .Iadd.28.  A method of measuring at least the pH value of a sample comprising the steps of generating a light beam having a predetermined color characteristic; generating light signals indicative of the pH value of a sample to be measured by positioning an indicator having a light-transmissive surface positioned to be impinged by said light beam, a diffusion membrane adapted to be placed in the proximity of a sample and being selectively permeable to a component of the sample which will allow a pH measurement of the sample to be made, and a pH indicating substance which is capable of fluorescing positioned to be impinged by the light beam penetrating said light-transmissive surface and by said component penetrating said diffusion membrane, said pH indicating substance responding when illuminated by said incident light beam by emitting a resultant light beam having a fluorescent emitted component which has a color characteristic different from said predetermined color characteristic and is related to the pH value of the sample; conducting said resultant light beam away from said indicating substance through said light-transmissive surface; and discriminating said emitted component from said resultant light beam so that the change in the color characteristic of said indicating substance can be measured and correlated with the pH 
     
     
        value of the sample. .Iaddend. .Iadd.29.  A method as defined in claim 28 wherein said sample is blood. .Iaddend. .Iadd.30. A method as defined in claim 28 wherein the pH indicating substance is beta-methyl-umbelliferon. .Iaddend. .Iadd.31. A method of measuring the concentration of carbon dioxide in a sample comprising the steps of generating a light beam having a predetermined color characteristic; generating light signals from which the concentration of carbon dioxide in a sample to be measured can be determined by positioning an indicator having a light-transmissive surface positioned to be impinged by said light beam, a diffusion membrane adapted to be placed in the proximity of a sample and being selectively permeable to at least a carbon dioxide component thereof, and an indicating substance which is capable of fluorescing positioned to be impinged by the light beam penetrating said light-transmissive surface and by said carbon dioxide component penetrating said diffusion membrane, said indicating substance responding when illuminated by said incident light beam by emitting a resultant light beam having a fluorescent emitted component which has a color characteristic different from said predetermined color characteristic and is related to the concentration of carbon dioxide in the sample; conducting said resultant light beam away from said indicating substance through said light-transmissive surface; discriminating said emitted component from said resultant light beam so that the change in the color characteristic of said indicating substance can be ascertained; and correlating the changes in the color characteristic with the concentration 
     
     
        of carbon dioxide in the sample. .Iaddend. .Iadd.32.  A method as defined in claim 31 wherein said indicating substance includes a pH indicating substance. .Iaddend. .Iadd.33. In an arrangement for measuring the concentration of gases in a sample, a combination comprising means for generating a monochromatic light beam having a predetermined color characteristic; indicating means for generating light signals indicative of the concentration of gases in a sample to be measured, including a light transmissive surface positioned to be impinged by said monochromatic light beam, a diffusion membrane of silicone adapted to be placed in proximity of a sample and being permeable to a selected gas component thereof, and an indicating substance sealingly embedded throughout said diffusion membrane and positioned to be impinged by said monochromatic light beam penetrating said light-transmissive surface and by said gas component penetrating said diffusion membrane, said indicating substance reacting when illuminated by said incident monochromatic light beam by emitting a resultant light beam having an emitted component which has a color characteristic different from said predetermined color characteristic; means for conducting said resulting light beam away from said indicating substance through said light transmissive surface; and means for discriminating said emitted component from said resultant light beam so that the change in the color characteristic of said indicating substance can be measured and correlated with the concentration of gases 
     
     
        in the sample. .Iaddend. .Iadd.34.  In an arrangement for measuring the concentration of carbon dioxide in a sample, a combination comprising means for generating a light beam having a predetermined color characteristic; indicating means for generating light signals from which the concentration of carbon dioxide in a sample to be measured can be determined, including a light transmissive surface positioned to be impinged by said light beam, a diffusion membrane adapted to be placed in proximity of a sample and being permeable to at least a carbon dioxide component thereof, and an indicating substance which is capable of fluorescing positioned to be impinged by said light beam penetrating said light-transmissive surface and by said carbon dioxide component penetrating said diffusion membrane, said indicating substance responding when illuminated by said incident light beam by emitting a resultant light beam having a fluorescent emitted component which has a color characteristic different from said predetermined color characteristic and is related to the concentration of carbon dioxide in the sample; means for conducting said resulting light beam away from said indicating substance through said light transmissive surface; means for discriminating said emitted component from said resultant light beam so that the change in the color characteristic of said indicating substance can be ascertained and means for correlating the change in the color characteristic with the concentration of carbon dioxide in the sample. .Iaddend. .Iadd.35. A method as defined in claim 34 wherein said indicating substance includes a 
     
     
        pH indicating substance. .Iaddend. .Iadd.36.  In an arrangement for measuring at least one of the characteristics of a sample wherein the sample characteristics consist essentially of the pH value and the concentration of gases in the sample, a combination comprising means for generating a light beam having a predetermined color characteristic; indicating means for generating light signals indicative of the sample characteristic to be measured, including a light transmissive surface positioned to be impinged by said light beam, a selectively permeable diffusion membrane of silicone adapted to be placed in proximity of a sample and being permeable to a component thereof, and an indicating substance in said diffusion membrane and positioned to be impinged by said light beam penetrating said light-transmissive surface and by said component penetrating said diffusion membrane, said indicating substance being capable of fluorescing and reacting when illuminated by said incident light beam by emitting a resultant light beam having a fluorescent emitted component which has a color characteristic different from said predetermined color characteristic; means for conducting said resultant light beam away from said indicating substance through said light transmissive surface; and means for discriminating said emitted component from said resultant light beam so that the change in the color characteristic of said indicating substance can be measured and correlated 
     
     
        with the sample characteristic to be measured. .Iaddend. .Iadd.37.  An arrangement as defined in claim 36 wherein the indicating substance is mixed with the membrane. .Iaddend. .Iadd.38. An arrangement as defined in claim 36 including an absorption surface facing said indicating substance and being between the indicating substance and the sample. .Iaddend. .Iadd.39. An arrangement as defined in claim 36 including a reflective surface facing said indicating substance and being between the indicating substance and the sample. .Iaddend. .Iadd.40. An arrangement as defined in claim 36 wherein said indicating substance is sealingly embedded throughout said diffusion membrane. .Iaddend. .Iadd.41. An arrangement as defined in claim 40 wherein the membrane includes a polymer and said polymer is mixed with the indicating substance. .Iaddend. .Iadd.42. An arrangement as defined in claim 36 wherein said membrane is permeable to a component of the sample which will allow a pH measurement of the blood to be made and said indicating substance is a pH indicating substance. 
     
     
        .Iaddend. .Iadd.43.  An arrangement as defined in claim 42 wherein said indicating substance is sealingly embedded throughout said diffusion membrane and said membrane includes a polymer and said polymer is mixed with the indicating substance. .Iaddend. .Iadd.44. An arrangement as defined in claim 36 wherein said membrane is permeable to at least a carbon dioxide component of the sample and said predetermined color characteristic is related to the concentration of carbon dioxide in the sample. .Iaddend. .Iadd.45. An arrangement as defined in claim 44 wherein said indicating substance is sealingly embedded throughout said diffusion membrane and said membrane includes a polymer and said polymer is mixed 
     
     
        with the indicating substance. .Iaddend. .Iadd.46.  In an arrangement for measuring the concentration of gases in a sample, a combination comprising means for generating a monochromatic light beam having a predetermined color characteristic; indicating means for generating light signals indicative of the concentration of gases in a sample to be measured, including a light transmissive surface positioned to be impinged by said monochromatic light beam, a diffusion membrane adapted to be placed in proximity of a sample and being permeable to a selected gas component thereof, and an indicating substance sealingly embedded throughout said diffusion membrane and positioned to be impinged by said monochromatic light beam penetrating said light-transmissive surface and by said gas component penetrating said diffusion membrane, said indicating substance reacting when illuminated by said incident monochromatic light beam by emitting a resultant light beam having an emitted component which has a color characteristic different from said predetermined color characteristic; means for conducting said resulting light beam away from said indicating substance through said light transmissive surface; and means for discriminating said emitted component from said resultant light beam so that the change in the color characteristic of said indicating substance can be measured and correlated with the concentration of gases in the sample, said indicating substance being betamethyl-umbelliferone. 
     
     
        .Iaddend. .Iadd.47.  In an apparatus for measuring at least one of the characteristics of blood within a body wherein the sample characteristics consist essentially of the pH value and the concentration of gases in the blood, a combination comprising: means for generating a light beam having a predetermined color characteristic;   a catheter receivable in a vein or artery and having a distal end, said catheter including indicating means for generating light signals indicative of the sample characteristic to be measured and a light-conductive cable means having an input end for conducting the light beam from the input end to the indicating means;   said indicating means including a light-transmissive surface positioned to be impinged by said light beam, a diffusion membrane permeable to a selected component of the blood, and an indicating substance which fluoresces positioned to be impinged by said light beam penetrating said light-transmissive surface and by said component penetrating said diffusion membrane, each of said light-transmissive surface, diffusion membrane and indicating substance being near said distal end of said catheter, said indicating substance being in said diffusion membrane and responding when illuminated by said incident light beam by emitting a resultant light beam having a fluorescent emitted component which has a predetermined color characteristic different from said predetermined color characteristic, said catheter including light conductive cable means for conducting said resulting light beam away from said indicating substance; and   means for discriminating said emitted component from said resultant light beam received from said last-mentioned light conductive cable means so that the change in the predetermined color characteristic of said indicating substance can be measured and correlated with the sample characteristic to be measured. .Iaddend. .Iadd.48. An apparatus as defined in claim 47 wherein the membrane includes a polymer and said polymer is   
     
     
        mixed with the indicating substance. .Iaddend. .Iadd.49.  An apparatus as defined in claim 47 wherein the membrane includes silicone. .Iaddend. .Iadd.50. In an apparatus for measuring at least one of the characteristics of blood within a body wherein the sample characteristics consist essentially of the pH value and the concentration of gases in the blood, a combination comprising: means for generating a light beam having a predetermined color characteristic;   a catheter receivable in a vein or artery and having a distal end, said catheter including indicating means for generating light signals indicative of the sample characteristic to be measured and a light-conductive cable means having an input end for conducting the light beam from the input end to the indicating means;   said indicating means including a light-transmissive surface positioned to be impinged by said light beam, a diffusion membrane permeable to a selected component of the blood, and an indicating substance which fluoresces positioned to be impinged by said light beam penetrating said light-transmissive surface and by said component penetrating said diffusion membrane, each of said light-transmissive surface, diffusion membrane and indicating substance being near said distal end of said catheter, said indicating substance responding when illuminated by said incident light beam by emitting a resultant light beam having a fluorescent emitted component which has a predetermined color characteristic different from said predetermined color characteristic, said catheter including light conductive cable means for conducting said resulting light beam away from said indicating substance; and   means for discriminating said emitted component from said resultant light beam received from said last-mentioned light conductive cable means so that the change in the predetermined color characteristic of said indicating substance can be measured and correlated with the sample characteristic to be measured. .Iaddend. .Iadd.51. An apparatus for measuring at least one of the characteristics of blood within a body wherein the sample characteristics consist essentially of the pH value and the concentration of gases in the blood, the apparatus is adapted to receive a light beam having a predetermined color characteristic and is coupled to provide an optical signal to discriminating means, said apparatus comprising:   indicating means for generating light signals indicative of the sample characteristic to be measured;   a light-conductive cable means having an input end for receiving the light beam and conducting the light beam to the indicating means;   said indicating means including a light-transmissive surface positioned to be impinged by said light beam, a diffusion membrane permeable to a selected component of the blood, an indicating substance which fluoresces positioned to be impinged by said light beam penetrating said light-transmissive surface and by said component penetrating said diffusion membrane, said apparatus being receivable in a vein or artery and having a distal end, each of said light-transmissive surface, diffusion membrane and indicating substance being near said distal end of said apparatus, said indicating substance responding when illuminated by said incident light beam by emitting a resultant light beam having a fluorescent emitted component which has a color characteristic different from said predetermined color characteristic; and   1ight conductive cable means for conducting said resulting light beam away from said indicating substance to the light discriminating means whereby the light discriminating means can discriminate said emitted component from said resultant light beam so that the change in the color characteristic of said indicating substance can be measured and correlated with the sample characteristic to be measured. .Iaddend. .Iadd.52. An apparatus as defined in claim 51 wherein said membrane is permeable to a component of the blood which will allow a pH measurement of the blood to be made and said indicating substance is a pH indicating substance. .Iaddend. .Iadd.53. An apparatus as defined in claim 51 wherein said membrane is permeable to at least a carbon dioxide component of the blood and said predetermined color characteristic is related to the concentration of carbon dioxide in the blood. .Iaddend. .Iadd.54. An apparatus as defined in claim 51 including an absorption surface facing said indicating substance and being between the indicating substance and the blood. .Iaddend. .Iadd.55. An apparatus as defined in claim 51 including a reflective surface facing said indicating substance and being between the indicating substance and the blood. .Iaddend.