Patent US5093266A successfully refreshed from Google Patents.
US5093266A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sensor system
Assignee: TGC RESEARCH Ltd
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Filing: 1989-02-27
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Granted: 1992-03-03
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Expires: 2009-02-27
Abstract
Abstract A sensor system for determining the pH or carbon dioxide concentration of a liquid medium comprising, in combination, a pH-insensitive fluorescent indicator and a PH-sensitive fluorescent indicator which act in concert or a single fluorescence indicator which emits fluorescent signals of different wavelengths in different carriers, which system(s) produce diverging signals, the ratio of which provides an accurate and stable determination of the parameter being measured. A method for determining pH and CO 2 concentration is also disclosed.
Inventors
- 👤 Matthew J. Leader
- 👤 Tadao Kamiya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 09:27
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/62; G01N21/63; G01N21/64; G01N21/6428; G01N21/643; G01N21/75; G01N21/77; G01N21/7703; G01N21/01; G01N21/03; G01N2021/0385; G01N2021/6417; G01N2021/6421; G01N2021/6434; G01N2021/6439; G01N2021/6441; G01N2021/7706; G01N2021/772; G01N2021/775; G01N2021/7769; G01N2021/7786; G01N21/78; G01N21/80; Y; Y10; Y10T; Y10T436/00; Y10T436/20; Y10T436/204998
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
150 words
A sensor system for determining the pH of a liquid medium which comprises, in combination, a first fluorescent indicator whose fluorescence emission is insensitive to pH and a second fluorescent indicator whose fluorescence emission is highly sensitive to solution pH, which indicator combination is adapted to respond when a source of excitation radiation of wavelength λ o is applied to the system such that said first fluorescent indicator is selectively excited by said excitation radiation to emit pH-insensitive fluorescence emission at wavelength λ 1 , which emission overlaps the excitation radiation spectrum of said second fluorescent indicator, and said second indicator being excited by said emission radiation of wavelength λ 1 and in turn emitting a pH-dependent fluorescence emission of wavelength λ 2 , the ratio of intensities of the radiation of wavelengths λ 1/ λ 2 providing a highly accurate, stable determination of the pH of said liquid medium.
Claim 2
Dependent Claim
150 words
A sensor system for determining the pH of a liquid medium which comprises, in combination, a first fluorescent indicator whose fluorescence emission is insensitive to pH and a second fluorescent indicator whose fluorescence emission is highly sensitive to solution pH, which indicator combination is adapted to respond when a source of excitation radiation of wavelength λ o is applied to the system such that said first fluorescent indicator is selectively excited by said excitation radiation to emit pH-insensitive fluorescence emission at wavelength λ 1 , which emission overlaps the excitation radiation spectrum of said second fluorescent indicator, and said second indicator being excited by said emission radiation of wavelength λ 1 and in turn emitting a pH-dependent fluorescence emission of wavelength λ 2 , the ratio of intensities of the radiation of wavelengths λ 1/ λ 2 providing a highly accurate, stable determination of the pH of said liquid medium.
Claim 3
Dependent Claim
47 words
A sensor system according to claim 1, which includes an optical fiber having a distal end and a proximal end and in which said combination of fluorescent indicators is attached to said distal end and said proximal end is adapted to receive excitation radiation from said source.
Claim 4
Dependent Claim
21 words
A sensor system according to claim 1, in which said first fluorescent indicator is 6,7-dimethoxycoumarin or a pH- insensitive coumarin derivative.
Claim 5
Dependent Claim
18 words
A sensor system according to claim 3, in which said second fluorescent indicator is 8-hydroxy-1,3, 6-pyrenetrisulfonic acid (HPTA).
Claim 6
Independent Claim
176 words
A method for determining the pH of a liquid medium which comprises contacting said medium with a sensor system comprising, in combination, a first fluorescent indicator whose fluorescence emission is insensitive to pH and a second fluorescent indicator whose fluorescence emission is highly sensitive to solution pH, subjecting said sensor system to excitation radiation of a predetermined wavelength λ o , thereby selectively exciting said first fluorescent indicator to emit a pH-insensitive fluorescence emission at a wavelength of λ 1 , which emission overlaps the excitation radiation spectrum of said second fluorescent indicator and thus excites said second indicator to emit a pH-dependent fluorescence emission of wavelength λ 2 , and measuring either (i) the ratio of intensities of the emitted radiation of wavelengths λ 1/ λ 2 , or (ii) the ratio derived from the intensity of the emitted radiation of wavelength λ 1 and the intensity at the isobestic point between the emission curves of said first and second indications, thereby obtaining a highly accurate, stable determination of the pH of said liquid medium.
Claim 7
Independent Claim
176 words
A method for determining the pH of a liquid medium which comprises contacting said medium with a sensor system comprising, in combination, a first fluorescent indicator whose fluorescence emission is insensitive to pH and a second fluorescent indicator whose fluorescence emission is highly sensitive to solution pH, subjecting said sensor system to excitation radiation of a predetermined wavelength λ o , thereby selectively exciting said first fluorescent indicator to emit a pH-insensitive fluorescence emission at a wavelength of λ 1 , which emission overlaps the excitation radiation spectrum of said second fluorescent indicator and thus excites said second indicator to emit a pH-dependent fluorescence emission of wavelength λ 2 , and measuring either (i) the ratio of intensities of the emitted radiation of wavelengths λ 1/ λ 2 , or (ii) the ratio derived from the intensity of the emitted radiation of wavelength λ 1 and the intensity at the isobestic point between the emission curves of said first and second indications, thereby obtaining a highly accurate, stable determination of the pH of said liquid medium.
Claim 8
Dependent Claim
56 words
A method according to claim 5, in which the sensor system includes an optical fiber having a distal end and a proximal end, said combination of said first and second fluorescent indicators is attached to the distal end of said optical fiber and said proximal end is adapted to receive excitation radiation from an appropriate source.
Claim 9
Dependent Claim
60 words
A method according to claim 6, in which said excitation radiation is laser radiation of wavelength, λ o , 337 nm, said first fluorescent indicator is 6, 7-dimethoxycoumarin which emits fluorescent radiation of wavelength, λ 1 ,435 nm and said second, pH-sensitive, fluorescent indicator is 8-hydroxy-1, 3, 6-pyrenetrisulfonic acid which emits fluorescent radiation of wavelength, λ 2 , 510 nm.
Claim 10
Dependent Claim
183 words
A sensor system for the determination of the concentration of carbon dioxide in a liquid medium which comprises, in combination, a first fluorescent indicator whose fluorescence emission is insensitive to pH and a second fluorescent indicator whose fluorescent emission is highly sensitive to solution pH, which indicator combination is associated with a bicarbonate solution bounded by a carbon dioxide-permeable membrane, and is adapted to respond when a source of excitation radiation of wavelength λ o is applied to the system such that said first fluorescent indicator is selectively excited by said excitation radiation to emit a pH-insensitive fluorescence emission at wavelength λ 1 , which emission overlaps the excitation radiation spectrum of said second fluorescent indicator, said second indicator being excited by said emission radiation of wavelength λ 1 , and in turn emitting a pH-dependent fluorescence emission of wavelength λ 2 , the ratio of intensities of the radiation of wavelengths λ 1 /λ 2 providing an indication of the solution pH within the membrane and thereby a highly accurate, stable determination of the concentration of carbon dioxide in the liquid medium.
Claim 11
Dependent Claim
183 words
A sensor system for the determination of the concentration of carbon dioxide in a liquid medium which comprises, in combination, a first fluorescent indicator whose fluorescence emission is insensitive to pH and a second fluorescent indicator whose fluorescent emission is highly sensitive to solution pH, which indicator combination is associated with a bicarbonate solution bounded by a carbon dioxide-permeable membrane, and is adapted to respond when a source of excitation radiation of wavelength λ o is applied to the system such that said first fluorescent indicator is selectively excited by said excitation radiation to emit a pH-insensitive fluorescence emission at wavelength λ 1 , which emission overlaps the excitation radiation spectrum of said second fluorescent indicator, said second indicator being excited by said emission radiation of wavelength λ 1 , and in turn emitting a pH-dependent fluorescence emission of wavelength λ 2 , the ratio of intensities of the radiation of wavelengths λ 1 /λ 2 providing an indication of the solution pH within the membrane and thereby a highly accurate, stable determination of the concentration of carbon dioxide in the liquid medium.
Claim 12
Dependent Claim
51 words
A sensor system according to claim 8, which includes an optical fiber having a distal end and a proximal end and in which said combination of fluorescent indicators, bicarbonate solution and membrane is attached to said distal end and said proximal end is adapted to receive excitation radiation from said source.
Claim 13
Dependent Claim
21 words
A sensor system according to claim 9, in which said first fluorescent indicator is 6, 7-dimethoxycoumarin or a pH-insensitive coumarin derivative.
Claim 14
Dependent Claim
18 words
A sensor system according to claim 10, in which said second fluorescent indicator is 8-hydroxy-1, 3, 6-pyrenetrisulfonic acid.
Claim 15
Dependent Claim
44 words
A sensor system according to claim 11, in which said first fluorescent indicator is bonded directly to said optical fiber and said second fluorescent indicator is suspended in a gel of carboxymethyl cellulose containing said bicarbonate solution and bounded by a silicone rubber membrane.
Claim 16
Independent Claim
207 words
A method for determining the concentration of carbon dioxide in a liquid medium which comprises contacting said medium with a sensor system comprising, in combination, a first fluorescent indicator whose fluorescence emission is insensitive to pH and a second fluorescent indicator whose fluorescence emission is highly sensitive to solution pH, which indicators are associated with a bicarbonate solution bounded by a carbon dioxide-permeable membrane, subjecting said sensor system to excitation radiation of a predetermined wavelength λ o , thereby selectively exciting said first fluorescent indicator to emit a pH-insensitive fluorescence emission at a wavelength of λ 1 , which emission overlaps the excitation radiation spectrum of said second fluorescent indicator and thus excites said second indicator to emit a pH-dependent fluorescent emission of wavelength λ 2 , and measuring either (i) the ratio of intensities of the emitted radiation of wavelengths λ 1 /λ 2 , or (ii) the ratio derived from the intensity of the emitted radiation of wavelength λ 1 and the intensity at the isobestic point between the emission curves of said first and second indications, thereby obtaining an indication of the solution pH within the membrane and thus a highly accurate, stable determination of the concentration of carbon dioxide in the liquid medium.
Claim 17
Independent Claim
207 words
A method for determining the concentration of carbon dioxide in a liquid medium which comprises contacting said medium with a sensor system comprising, in combination, a first fluorescent indicator whose fluorescence emission is insensitive to pH and a second fluorescent indicator whose fluorescence emission is highly sensitive to solution pH, which indicators are associated with a bicarbonate solution bounded by a carbon dioxide-permeable membrane, subjecting said sensor system to excitation radiation of a predetermined wavelength λ o , thereby selectively exciting said first fluorescent indicator to emit a pH-insensitive fluorescence emission at a wavelength of λ 1 , which emission overlaps the excitation radiation spectrum of said second fluorescent indicator and thus excites said second indicator to emit a pH-dependent fluorescent emission of wavelength λ 2 , and measuring either (i) the ratio of intensities of the emitted radiation of wavelengths λ 1 /λ 2 , or (ii) the ratio derived from the intensity of the emitted radiation of wavelength λ 1 and the intensity at the isobestic point between the emission curves of said first and second indications, thereby obtaining an indication of the solution pH within the membrane and thus a highly accurate, stable determination of the concentration of carbon dioxide in the liquid medium.
Claim 18
Dependent Claim
67 words
A method according to claim 13, in which the sensor system includes an optical fiber having a distal end and a proximal end, said combination of said first and second indicators, bicarbonate solution and membrane is attached to said distal end and said excitation radiation is transmitted, from a source adjacent to said proximal end, through said optical fiber from said proximal end to said distal end.
Claim 19
Dependent Claim
59 words
A method according to claim 14, in which said excitation radiation is laser radiation of wavelength, λ o , 337 nm, said first fluorescent indicator is 6,7-dimethoxycoumarin which emits fluorescent radiation wavelength, λ 1 , 435 nm and said second, pH-sensitive, fluorescent indicator is 8-hydroxy-1, 3, 6-pyrenetrisulfonic acid which emits fluorescent radiation of wavelength, λ 2 , 510 nm.
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