Multi-purpose voltametric analyzer
First Claim
1. Apparatus for measuring the concentration of a substance in a solution wherein the concentration of the substance in solution can be directly correlated with the depletion of oxygen in an enzymatically catalyzed reaction of the substance, said apparatus comprising:
- (a) an enzyme sensor comprising;
(i) an oxygen detector having two electrodes enclosed in a probe and having a sensitive area on the probe tip, said oxygen detector effectively producing a detector output current signal representative of the dissolved oxygen contacting said sensitive area;
(ii) a layer of at least one oxidase enzyme held against said sensitive area on the probe tip, wherein said oxidase enzyme effectively catalyzing the reaction of the substance with oxygen;
(b) electronic signal conditioning circuitry connected to said oxygen detector comprising;
(i) circuit means, having an input and an output, for converting a current signal to a voltage signal;
(ii) means for conducting said detector output current signal to the input of said circuit means wherein said detector output current signal is converted to a detector voltage signal;
(iii) means for establishing a first measurement signal at the output of said circuit means wherein said first measurement signal is representative of the concentration of dissolved oxygen contacting said sensitive area in the absence of the enzymatically catalyzed reaction of the substance with oxygen;
(iv) means for establishing an offset correction current for said detector output current which nulls said first measurement signal; and
(v) means for establishing a second measurement signal at the output of said circuit means wherein said second measurement signal is representative of the concentration of dissolved oxygen contacting said sensitive area in the presence of the enzymatically catalyzed reaction of the substance with oxygen and is thereby representative of the concentration of the substance in the solution.
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Accused Products
Abstract
An instrument for measuring the concentration of a wide variety of important chemical and biochemical substances is provided which comprises an enzyme based voltametric sensor, and electronic circuitry for conditioning an output signal from the sensor. The instrument includes one or more aqueous oxidase enzymes mechanically coupled to a polarographic cell oxygen detector wherein the concentration of a substance is inferred from measurement of the depletion of oxygen resulting from an oxidation reaction catalyzed by the oxidase enzyme. The electronic circuitry includes current to voltage conversion, nulling an unneeded base current signal, and temperature compensation.
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Citations
9 Claims
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1. Apparatus for measuring the concentration of a substance in a solution wherein the concentration of the substance in solution can be directly correlated with the depletion of oxygen in an enzymatically catalyzed reaction of the substance, said apparatus comprising:
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(a) an enzyme sensor comprising; (i) an oxygen detector having two electrodes enclosed in a probe and having a sensitive area on the probe tip, said oxygen detector effectively producing a detector output current signal representative of the dissolved oxygen contacting said sensitive area; (ii) a layer of at least one oxidase enzyme held against said sensitive area on the probe tip, wherein said oxidase enzyme effectively catalyzing the reaction of the substance with oxygen; (b) electronic signal conditioning circuitry connected to said oxygen detector comprising; (i) circuit means, having an input and an output, for converting a current signal to a voltage signal; (ii) means for conducting said detector output current signal to the input of said circuit means wherein said detector output current signal is converted to a detector voltage signal; (iii) means for establishing a first measurement signal at the output of said circuit means wherein said first measurement signal is representative of the concentration of dissolved oxygen contacting said sensitive area in the absence of the enzymatically catalyzed reaction of the substance with oxygen; (iv) means for establishing an offset correction current for said detector output current which nulls said first measurement signal; and (v) means for establishing a second measurement signal at the output of said circuit means wherein said second measurement signal is representative of the concentration of dissolved oxygen contacting said sensitive area in the presence of the enzymatically catalyzed reaction of the substance with oxygen and is thereby representative of the concentration of the substance in the solution. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for obtaining an analysis of the concentration of a substance in a solution wherein the concentration of the substance can be directly correlated with the depletion of oxygen in an enzymatically catalyzed reaction of the substance and wherein an oxygen detector having two electrodes enclosed in a probe and having a layer of at least one oxidaze enzyme held against a sensitive area on the probe tip, generates a detector output current signal, and wherein electronic signal conditioning circuit means having an input and an output is connected to said oxygen detector and converts said detector output current signal to a voltage signal, said method comprising the steps of:
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establishing a first measurement signal at said output of said signal conditioning circuit means wherein said first measurement signal is representative of the concentration of dissolved oxygen contacting said sensitive area in the absence of a catalytic reaction of the substance with oxygen; establishing an offset correction current for said detector output current which nulls said first measurement signal; and establishing a second measurement signal at the output of said signal conditioning circuit means after nulling said first measurement signal wherein said second measurement signal is representative of the concentration of dissolved oxygen contacting said sensitive area in the presence of a catalytic reaction of the substance with oxygen and is thereby representative of the concentration of the substances in a solution. - View Dependent Claims (8, 9)
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Specification