Master's thesis presents definition of polarization impedance, which is present on contact electrode – tissue and can spoil our mesaruemnt. Known solutions for its reducement are presented and measurements with results are provided. Measurements program was written in LabVIEW. Measurements were conducted on 6 pairs of electrodes, 7 different concentrations of the electrolyte solution, 9 voltage amplitudes and in frequency range of 20 Hz – 100 kHz. Comparison with scientific articles was made and results were presented using mathematical model. With usage of mathematic approximation, polarization impedance impact was completely excluded.
In first chapter, theoretical explanation of electrode polarization impedance is presented, together with suggested solutions for it's reducement.
In second chapter, bioimpedance measurement usage in clinical applications and electroporation processes is presented.
Third chapter presents data of used measurement instrument, measurement system preparation, written program for measurements and choice of appropriate measurement cup.
In fourth chapter, results are shown. Every subchapter analyzes polarization impedance dependency of particular parameter. Parameters are concentration of solution, voltage amplitude, electrode type, electrode thickness, electrode length and measuring cup. Results are shown in graphic form, so it is clear to determine where polarization impedance impact is the lowest. Charts of resistance R, capacitance C and calculated absolute impedance |Z| are shown. For clearer understanding, term of absolute impedance is generally replaced with term of impedance Z during thesis.
In fifth chapter, results are analyzed using mathematical model. Comparison of mathematical model's parameters is made for multiple concentrations of electrolyte solutions and voltage amplitudes. Experiment of mathematical approximation is made to reduce polarization impedance impact from conductivity measurements.
In sixth chapter, thesis findings and limits are presented. Comparisons with scientific articles are made and results of mathematic approximation are commented. Possible improvements and upgrades of thesis are suggested.
In last chapter, conclusions of master's thesis are given.
Thesis finding: polarization impedance is dependent of many parameters and can be successfully excluded from measurement using corect mathematical model.