Method for measuring the concentration or change in concentration of a redox-active substance and corresponding device
First Claim
1. A method for measuring at least one of a concentration and change in concentration of a redox-active substance as a mediator in a molecular-biological detection system, in which as a result of application of suitable potentials to a working electrode, at least one of a reduction process and an oxidation process takes place as a redox reaction, the method comprising:
- measuring an oxidation current to obtain a measuring phase;
measuring a reduction current to obtain a relaxation phase;
pulsing the potential of the working electrode, and alternately forming the measuring phases and the relaxation phases;
selecting measuring-phase pulse lengths so that, at the end of the pulse, a capacitive current is small in comparison with a Faraday current; and
selecting relaxation-phase pulse lengths so that, at the end of the pulse, a concentration gradient is relaxed such that at a beginning of a following measuring phase, the change in concentration of the mediator, brought about by the measurement of the mediator, is reversible.
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Abstract
In order to follow the change in concentration of a redox-active substance, potential suitable for a reducing process or oxidation process are applied to the working electrode of a measuring device. The potential of the working electrode is pulsed and measuring phases and relaxation phases are alternately produced, the pulse lengths of the measuring phase and relaxation phase being predetermined in a suitable manner. In this manner, a rapid relaxation of the concentration gradient is forced electrochemically so that the measurement can be carried out on simple transducer arrays. The device includes a transducer array in addition to a suitable potentiostat. The transducer array may include a planar metal substrate on which at least one flexible insulator having a firm connection between the metal surface and the insulator surface is located. The array is generated by suitably structuring the substrate.
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Citations
16 Claims
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1. A method for measuring at least one of a concentration and change in concentration of a redox-active substance as a mediator in a molecular-biological detection system, in which as a result of application of suitable potentials to a working electrode, at least one of a reduction process and an oxidation process takes place as a redox reaction, the method comprising:
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measuring an oxidation current to obtain a measuring phase; measuring a reduction current to obtain a relaxation phase; pulsing the potential of the working electrode, and alternately forming the measuring phases and the relaxation phases; selecting measuring-phase pulse lengths so that, at the end of the pulse, a capacitive current is small in comparison with a Faraday current; and selecting relaxation-phase pulse lengths so that, at the end of the pulse, a concentration gradient is relaxed such that at a beginning of a following measuring phase, the change in concentration of the mediator, brought about by the measurement of the mediator, is reversible. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification