FIELD: physics.
SUBSTANCE: invention can be used for determining amount of analysed substance in a liquid sample and can be used in medical conditions such as diabetes, since a patient with symptoms of such a disease requires regular self-checking of glucose concentration level in the blood. An electrochemical sensor for determining concentration of analysed substance in a liquid sample has a channel for receiving the liquid sample, first and second terminals, each of which can be electrically connected to an electric current sensor, a working electrode placed along the said channel for receiving the liquid sample, electrically connected to the first terminal; a counter electrode is electrically connected to the second terminal and has a low-resistance section, lying along the said channel below the working electrode, and a high-resistance section, lying along the said channel above the working electrode, a resistor is electrically connected to the high-resistance section of the counter electrode and the second terminal, a reagent is placed on the working electrode for reaction with the analysed substance and for generation of electrons, which are transferred to the working electrode. When a voltage profile is applied to the first and second terminals when there is electrical connection only between the high-resistance section of the counter electrode and the working electrode, the first current profile forms on the first and second terminals. When the same voltage profile is applied the first and second terminals when there is electrical connection between the low-resistance and high-resistance sections of the counter electrode and the working electrode, a second current profile, different from the first, forms on the first and second terminals.
EFFECT: invention allows for use of small volumes of samples (less than 10 mcm) for analysis.
33 cl, 4 dwg
