METHOD OF DETERMINING CONCENTRATION OF HYDROGEN IONS Russian patent published in 2012 - IPC G01N27/416 

FIELD: physics.

SUBSTANCE: in the method of determining concentration of hydrogen ions by using electrodes with high internal resistance to measure electrical parameters of the analysed medium based on the steady-state potential of the measured signal, which corresponds to the physical and chemical composition of the medium, which is generated from the dynamic potential difference between measuring and comparative electrodes of the measuring cell by accumulating ions on the measuring electrode, and recording a first time interval from the moment the measured signal equals the lower threshold value up to when it reaches the upper threshold value, a third threshold is additionally introduced between the upper and lower thresholds and a second time interval is recorded from the beginning of measurement until reaching the third threshold value, the level of which is determined in the range from the lower to the upper threshold based on minimum relative error between the analysed and modelled curves; the real value of the third threshold is the voltage amplitude which corresponds to minimum error; the steady-state potential value from which concentration of hydrogen ions is determined is determined from the multiple of the first time interval relative the second time interval.

EFFECT: high accuracy of determination owing to lower dynamic and systematic error.

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