Method of sensing with emission quenching sensors
First Claim
1. A method for sensing the concentration of an analyte in a medium comprising the steps of:
- exposing a sensing element to said medium, said sensing element comprising an emissive indicator configured for exposure to a quencher, said quencher comprising said analyte or a substance related to said analyte by a known relationship, and wherein said emissive indicator has a bimolecular quenching rate constant kq for said quencher and one or more fluoresence liftimes τ
o above a lowest lifetime τ
oL ;
exposing said sensing element to an excitation signal at a radial frequency ω
thereby causing said sensing element to emit an analyte concentration dependent signal or signals having a concentration dependent parameter which varies as a function of analyte concentration;
detecting said emitted signal(s) and providing detected signal(s);
univariantly processing at least one of said detected signals to derive the concentration dependent parameter thereby determining the concentration of said analyte in said medium, wherein said sensing element and said excitation signal are configured so as to provide an operating condition where the quantity {[(kq [Q])2 +ω
2 ]τ
o2 } is greater than 4 times the quantity {1+2kq τ
o [Q]} for all analyte concentrations within the operating range of interest and for all lifetimes τ
o greater than τ
oL, where [Q] is the concentration of said quencher in said sensing element.
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Abstract
The present invention relates to a sensing instrument and method for measuring the concentration of an analyte. The sensing instrument includes: a sensing element including at least a first emissive indicator characterized by a bimolecular quenching rate constant kq, one or more fluorescence lifetimes τo above a lowest lifetime τoL, and capable of emitting analyte concentration dependent signals when exposed to an excitation signal in the presence of quencher; an excitation system which provides an amplitude modulated excitation signal at one or more radial modulation frequencies ω; a detector; and a processor. The processor univariantly processes the detected signals and provides output signals representative of analyte concentration. The sensing element and/or excitation system are configured to enable the instrument to operate sufficiently within the condition [(kq [Q])2 +ω2 ]τo2 >>1+2kq τo [Q] such that a slope of the relationship between the concentration dependent parameter and analyte concentration is independent of τo variability and/or heterogeneity for all analyte concentrations within the operating range and for all lifetimes τ o greater than τoL.
58 Citations
32 Claims
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1. A method for sensing the concentration of an analyte in a medium comprising the steps of:
-
exposing a sensing element to said medium, said sensing element comprising an emissive indicator configured for exposure to a quencher, said quencher comprising said analyte or a substance related to said analyte by a known relationship, and wherein said emissive indicator has a bimolecular quenching rate constant kq for said quencher and one or more fluoresence liftimes τ
o above a lowest lifetime τ
oL ;exposing said sensing element to an excitation signal at a radial frequency ω
thereby causing said sensing element to emit an analyte concentration dependent signal or signals having a concentration dependent parameter which varies as a function of analyte concentration;detecting said emitted signal(s) and providing detected signal(s); univariantly processing at least one of said detected signals to derive the concentration dependent parameter thereby determining the concentration of said analyte in said medium, wherein said sensing element and said excitation signal are configured so as to provide an operating condition where the quantity {[(kq [Q])2 +ω
2 ]τ
o2 } is greater than 4 times the quantity {1+2kq τ
o [Q]} for all analyte concentrations within the operating range of interest and for all lifetimes τ
o greater than τ
oL, where [Q] is the concentration of said quencher in said sensing element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for sensing the concentration of an analyte in a medium comprising the steps of:
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exposing a sensing element to said medium, said sensing element comprising a matrix material and an emissive indicator, wherein said matrix material is permeable to a quencher comprising said analyte or a substance related to said analyte by a known relationship, and wherein said emissive indicator has a bimolecular quenching rate constant kq for said quencher, one or more fluoresence liftimes τ
o above a lowest lifetime τ
oL ;exposing said sensing element to a first excitation signal at a radial frequency ω
thereby causing said sensing element to emit an analyte concentration dependent signal or signals having a concentration dependent parameter which varies as a function of analyte concentration;detecting said emitted signal(s) and providing detected signal(s); processing univariantly at least one of said detected signals to derive the concentration dependent parameter thereby determining the concentration of said analyte in said medium, wherein said sensing element and said excitation signal are configured so as to provide an operating condition wherein the quantity {[(kq [Q])2 +ω
2 ]τ
o2 } is sufficiently greater than the quantity {1+2kq τ
o [Q]} such that a slope of the relationship between the concentration dependent parameter and quencher concentration is independent of τ
o variability for all analyte concentrations within the operating range of interest and for all lifetimes τ
o greater than τ
oL, where [Q] is the concentration of said quencher in said matrix. - View Dependent Claims (18, 19, 20)
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21. A method for sensing the concentration of oxygen in a medium comprising the steps of:
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exposing a sensing element to said medium, said sensing element comprising an emissive indicator configured for exposure to oxygen and an oxygen permeable matrix, wherein said emissive indicator has a bimolecular quenching rate constant kq for oxygen and one or more fluoresence liftimes τ
o above a lowest lifetime τ
oL, and wherein said matrix has an oxygen solubility constant a;exposing said sensing element to an excitation signal at a radial frequency ω
thereby causing said sensing element to emit an oxygen concentration dependent signal or signals having a concentration dependent parameter which varies as a function of oxygen concentration;detecting said emitted signal(s) and providing detected signal(s); univariantly processing at least one of said detected signals to derive the concentration dependent parameter thereby determining the concentration of oxygen in said medium, wherein said sensing element and said excitation signal are configured so as to provide an operating condition where the quantity {[(akq Po2)2 +ω
2 ]τ
o2 } is greater than 4 times the quantity {1+2akq τ
o Po2 } for all oxygen partial pressures within the operating range of 40 to 200 mm Hg and for all lifetimes τ
o greater than τ
oL. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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Specification