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. (C) 2007 Elsevier B.V. All rights reserved.