Portable and inexpensive electrochemical impedance spectroscopy system for characterization of saline solution impedance

Abstract

The developed portable and inexpensive EIS instruments can measure impedance spectra from 0.01 Hz to 100 kHz. The instruments include a programmable current source from 1 μA to 1 μA for adjusting the range of impedance of the sample, which is possibly from 10Ω to 300 kΩ, gain phase detector-based data acquisition, and microcontroller-PC-based software for controlling, collecting, and real-time plotting data in Bode and Nyquist diagram. The EIS system was validated by measuring dummy components' impedance, resulting in less than 2% error. The system can measure the sample's impedance and investigate the electrode-sample interface's double-layer phenomenon with the available frequency range. This phenomenon is experienced in every impedance measurement and can affect the interpretation of the measurement spectrum. Furthermore, the instrument is applied to characterize the impedance of two different saline solutions (KCl and MgCl2) and the double-layer phenomena between electrode-electrolytes.