FIELD: chemistry.
SUBSTANCE: group of inventions relates to detection of analytes in biological fluids. Method of determining capacitance of an electrochemical biosensor test cell of a test strip comprises steps of: depositing a fluid sample in electrochemical test cell; applying an oscillating signal of a predetermined frequency to electrochemical test cell; determining a phase angle between an output signal and oscillating signal from electrochemical test cell; measuring an amplitude of output signal from electrochemical test cell with confirmation of first sampling time interval for measurement of output signal based on predetermined sampling rate at output signal cycle with predetermined frequency and produce output signal sampling from cell with a second time sampling interval, different from first time sampling interval so that amplitude of each selected output signal is measured at end of each of second time sampling interval instead of first time interval; converting measured amplitude into a complex impedance of electrochemical test cell based on oscillating signal, phase angle and electrical resistance between test cell and connectors; and deriving a capacitance of electrochemical test cell based on complex impedance and predetermined frequency of electrochemical test cell, with evaluation of output signal to determine duration of time interval between each step change of output signal and installation of first time sampling interval, which is equal to time duration. Invention also discloses a method and a system for evaluating state of electrochemical test strip.
EFFECT: higher accuracy and efficiency of analysis.
29 cl, 11 dwg, 1 tbl
