Design and fabrication of a miniaturized electrochemical instrument and its preliminary evaluation

A simple microprocessor controlled mini-electrochemical (EC) instrument integrating with square wave voltammetry (SWV) was designed and fabricated. Direct digital frequency synthesizer (DDFS) was exploited in the circuit design to generate a linear and very low frequency scanning waveform for SWV. An ultra-low bias current, a high performance operational amplifier, a lock-in amplifier, and several noise reduction methods, such as cable selection, PCB cleaning, and guarding, were utilized to achieve the capability of ultra-low current measurement. The initial performance test of this SWV-based EC device was also conducted in different ferricyanide solutions. Compared with commercial electrochemical analyzers, the miniaturized EC instrument presented here has the characteristics of low-cost, small size, ease of use and reduced energy consumption. Due to its flexible design, this SWV-based instrument can easily be extended to meet the requirements of the portable and reliable EC chip device integrating other commonly used EC methods.