Design of and electronic system for the implementation of electrochemical measurement techniques: Voltammetry, Impedance Spectroscopy and Potentiometry

Abstract

The present project’s objective is the design of an electronic system for the implementation of electrochemical measurements: Cyclic Voltammetry, Variable Amplitude Pulse Voltammetry, Electrochemical Impedance Spectroscopy (EIS) and Potentiometry. It includes the whole implementation of the voltammetric techniques mentioned above, and provides a really advanced stage of the investigation needed to fully implement EIS and potentiometry techniques. Due to the variety of signals to be generated and measured (sinusoidal, triangular and square waveforms, frequencies from millihertz to megahertz and amplitudes from millivolts to 2 volts), the use of high speed AD and DA converters as well as a high performance digital processing block is required. In this project it has been decided to use a FPGA and AD and DA high speed 14 bits converters. Due to the nature of the electrochemical measurements the connection of the system to the electrodes has been made by using a potentiostat, which allows the control of the applied voltage to the electrodes as well as measure the current that flows through them. The stability problems that the potentiostat presents for certain measuring conditions have been studied and solved. The system incorporates 32 current scales which allow a vast variety of complex matrices. A software application has been developed to collect the measurements data, display them and store them in files for further processing. The validation for the voltammetric techniques is also included with tests made on tensioactive species. The experimental results are consistent with the theory considerations, which allow the validation of these measurement techniques.