Method of measuring the concentration of a substance in a sample solution
First Claim
1. A method for the absolute measurement of the concentration of a substance in a predetermined volume of a sample solution comprising;
- (a) providing an apparatus comprising first and second electrode structures and an enzyme channel between said first and second electrode structures containing an enzyme for catalyzing a reaction of a substance contained in a predetermined volume of a sample solution;
(b) providing a mixture of an excess of a mediator and said sample solution, presenting said mixture to the first electrode structure and applying a voltage to said first electrode structure effective to oxidize said mediator and electrochemically remove any interferent species present in said sample solution;
(c) passing the mixture through the enzyme channel effective to catalyze a reaction of all of said sample substance such that a quantity of said mediator is reduced;
(d) presenting the mixture to the second electrode structure and applying a voltage to said second electrode structure effective to completely re-oxidize all of said quantity of reduced mediator;
(e) measuring the current flowing through said second electrode structure required to completely re-oxidize all of said quantity of reduced mediator;
(f) integrating said current to provide a measurement of the quantity of charge required to completely re-oxidize all of said quantity of reduced mediator, and,calculating the concentration of the sample substance in said sample solution from said measurement.
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Abstract
An apparatus is provided for measuring the concentration of a substance in a sample solution. The apparatus comprises first electrode means, second electrode means and an enzyme channel between the first and second electrode means. The enzyme channel contains an enzyme for catalyzing a reaction of the substance whose concentration is to be measured. In use, a known volume of the sample solution is presented to the first electrode means in a test solution including an excess of a mediator, one of reduction or oxidation of the mediator being coupled to the reaction of the substance. The first electrode means is arranged to ensure that the mediator is respectively completely oxidized or reduced, and also to remove any interferent species. The test solution is then passed through the enzyme channel so as to permit reaction of all of the substance present in the solution, whereby a quantity of the mediator is respectively reduced or oxidized. The test solution is then presented to the second electrode means which are arranged to respectively oxidize or reduce the quantity of mediator which had been respectively reduced or oxidized. This produces a quantity of charge through the second electrode means which is measured by means for measuring said quantity of charge.
266 Citations
6 Claims
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1. A method for the absolute measurement of the concentration of a substance in a predetermined volume of a sample solution comprising;
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(a) providing an apparatus comprising first and second electrode structures and an enzyme channel between said first and second electrode structures containing an enzyme for catalyzing a reaction of a substance contained in a predetermined volume of a sample solution; (b) providing a mixture of an excess of a mediator and said sample solution, presenting said mixture to the first electrode structure and applying a voltage to said first electrode structure effective to oxidize said mediator and electrochemically remove any interferent species present in said sample solution; (c) passing the mixture through the enzyme channel effective to catalyze a reaction of all of said sample substance such that a quantity of said mediator is reduced; (d) presenting the mixture to the second electrode structure and applying a voltage to said second electrode structure effective to completely re-oxidize all of said quantity of reduced mediator; (e) measuring the current flowing through said second electrode structure required to completely re-oxidize all of said quantity of reduced mediator; (f) integrating said current to provide a measurement of the quantity of charge required to completely re-oxidize all of said quantity of reduced mediator, and, calculating the concentration of the sample substance in said sample solution from said measurement. - View Dependent Claims (2, 3)
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4. A method for the absolute measurement of the concentration of a substance in a predetermined volume of a sample solution comprising;
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(a) providing an apparatus comprising first and second electrode structures and an enzyme channel between said first and second electrode structures containing an enzyme for catalyzing a reaction of a substance contained in a predetermined volume of a sample solution; (b) providing a mixture of an excess of a mediator and said sample solution, presenting said mixture to the first electrode structure and applying a voltage to said first electrode structure effective to reduce said mediator and electrochemically remove any interferent species present in said sample solution; (c) passing the mixture through the enzyme channel effective to catalyze a reaction of all of said sample substance such that a quantity of said mediator is oxidized; (d) presenting the mixture to the second electrode structure and applying a voltage to said second electrode structure effective to completely re-reduce all of said quantity of oxidized mediator; (e) measuring the current flowing through said second electrode structure required to completely re-reduce all of said quantity of oxidized mediator; (f) integrating said current to provide a measurement of the quantity of charge required to completely re-reduce all of said quantity of oxidized mediator, and, calculating the concentration of the sample substance in said sample solution from said measurement. - View Dependent Claims (5, 6)
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Specification