Optical detection of oxygen
First Claim
1. Apparatus for detecting the presence of gaseous oxygen and measuring the amount present, comprising:
- a) means for producing substantially monochromatic excitation light;
b) a sensing element comprised of;
(1) a polar substrate having free hydroxyl groups at its surface;
(2) a luminophor compound, which is a conjugated aromatic carbonyl compound, deposited on the surface of said substrate wherein said luminophore compound is N-methylacridone; and
,(3) a halogenated hydrocarbon compound deposited on the surface of said substrate at locations adjacent to said carbonyl compound, wherein the halogenated hydrocarbon compound contains at least one halogen selected from the group consisting of chlorine, bromine, and iodine;
c) means for exposing said sensing element to said excitation light;
d) means for collecting light emitted by said carbonyl compound;
e) means for filtering said collected light to remove scattered excitation light and stray light which is collected along with said emitted light;
f) means for measuring the intensity of said filtered light;
g) means for exposing said sensing element to a sample environment comprising gaseous oxygen;
h) means for exposing said sensing element to calibration environments; and
,i) means for determining oxygen concentration in said sample environment by comparing light intensity measured while the sensing element is exposed to said sample environment to light intensities measured while the sensing element is exposed to said calibration environments.
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Abstract
This invention is a method and apparatus for detecting the presence of gaseous oxygen and measuring the amount present. In the practice of the invention, luminescence from a luminophor compound is quenched by oxygen. The luminiphor is a conjugated aromatic carbonyl. The intensity of the emitted light is related to the concentration of oxygen in the atmosphere surrounding the conjugated aromatic carbonyl compound. The luminophor compound is located on a polar substrate having free hydroxyl groups at its surface and also having at its surface, in locations adjacent to the luminophor compound, a halogenated hydrocarbon compound containing at least one halogen selected from a group consisting of chlorine, bromine, and iodine. In a preferred embodiment, the invention comprises an oxygen sensor utilizing a fiber-optic light guide to conduct excitation light to a substrate comprised of activated silica gel particles having methylene chloride and N-methylacridone co-deposited on them. A fiber-optic light guide is used to conduct emitted light away from the substrate.
41 Citations
17 Claims
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1. Apparatus for detecting the presence of gaseous oxygen and measuring the amount present, comprising:
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a) means for producing substantially monochromatic excitation light; b) a sensing element comprised of; (1) a polar substrate having free hydroxyl groups at its surface; (2) a luminophor compound, which is a conjugated aromatic carbonyl compound, deposited on the surface of said substrate wherein said luminophore compound is N-methylacridone; and
,(3) a halogenated hydrocarbon compound deposited on the surface of said substrate at locations adjacent to said carbonyl compound, wherein the halogenated hydrocarbon compound contains at least one halogen selected from the group consisting of chlorine, bromine, and iodine; c) means for exposing said sensing element to said excitation light; d) means for collecting light emitted by said carbonyl compound; e) means for filtering said collected light to remove scattered excitation light and stray light which is collected along with said emitted light; f) means for measuring the intensity of said filtered light; g) means for exposing said sensing element to a sample environment comprising gaseous oxygen; h) means for exposing said sensing element to calibration environments; and
,i) means for determining oxygen concentration in said sample environment by comparing light intensity measured while the sensing element is exposed to said sample environment to light intensities measured while the sensing element is exposed to said calibration environments. - View Dependent Claims (2, 3, 4)
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5. A sensor for gaseous oxygen comprised of:
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a) a polar substrate having free hydroxyl groups at its surface; b) a luminophor compound, which is a conjugated aromatic carbonyl compound, deposited on the surface of said substrate wherein said luminophore compound is N-methylacridone; c) a halogenated hydrocarbon compound deposited on the surface of said substrate at locations adjacent to said carbonyl compound, wherein the halogenated hydrocarbon compound contains at least one halogen selected from the group consisting of chlorine, bromine, and iodine; d) at least one fiber-optic light guide for conducting excitation light to said substrate; and
,e) at least one fiber-optic light guide for conducting light emitted by said carbonyl compound away from said substrate. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
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13. A method for detecting the presence of gaseous oxygen and measuring the amount present comprising:
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a) exciting a luminophor compound with substantially monochromatic light having wavelengths effective for absorption by said luminophor, wherein the luminophor is located on a polar substrate having free hydroxyl groups, wherein a halogenated hydrocarbon compound containing at least one halogen selected from the group consisting of chlorine, bromine, and iodine is located on the substrate at locations adjacent to the luminophor, and wherein the luminophor is N-methylacridone; b) collecting light emitted by the luminophor at wavelengths different from those of said excitation light; c) measuring the intensities of said collected light when said luminophor is located in a calibration environment comprising gaseous oxygen of at least two different concentrations, thus providing at least two intensity measurements; d) measuring the intensity of said collected light when said luminophor is located in a sample environment comprising gaseous oxygen; and
,e) determining the oxygen concentration of said sample environment by comparing said sample environment intensity to said calibration environment intensities. - View Dependent Claims (14, 15, 16, 17)
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Specification