Electrochemically-Driven Micropump for Fluid Flow and Delivery: Toward a Novel Micropump Design for Miniaturized Liquid Chromatographic and Flow Injection Analyses

This paper describes the development of a prototype fluid pumping system for incorporation into a miniaturized flow injection analyzer. The strategy couples the well-established capabilities of reagent-based flow injection analyses (FIA) with our novel concepts for the design of a miniaturized, low-power pumping system, i.e., an electrochemically-driven micropump. The basis of pump actuation relies on the electrochemically-induced surface tension changes at the electrolyte/mercury interface, resulting in a “piston-like” pumping process devoid of mechanically moving parts. We present herein the results from the preliminary performance tests of a miniaturized fluid flow system with the micropump. As described, the flow rates and pumping displacement volumes have been studied as a function of the amplitude and the frequency of the applied voltage waveform. Flow rates in the range of 5 to 1000 μL/min, displacement volumes as high as 10 μL per actuation cycle, and waveform frequencies up to 50 Hz have been demonstrated using a capillary column design for the flow system with ball-style check valves. Results using an optical detection format are presented as a concept demonstration of the integrated analysis system for a redox reaction. The long range objective is to demonstrate that our pumping system can serve as a cornerstone for the advancement of field deployable FIA and liquid chromatographic (LC) instrumentation that meets the chemical monitoring needs for space exploration as well as in the environmental and industrial arenas.