Development of a low-cost microfluidic capillary-electrophoresis system coupled with flow-injection and sequential-injection sample introduction (review)

Microfabrication techniques used for the production of MEMS (micro electro-mechanical systems) have been successfully used to produce highly efficient microfluidic capillary electrophoresis chip systems. A limitation of this approach are the difficulties associated with the creation of the micrometer-sized structures in glass or other substrates, which currently involve specialized and expensive lithographic and etching processes. A further limitation is that hitherto most microfluidic chips are not designed for continuous introduction of a series of different samples. which limits the overall throughput of such systems. This article reviews the development of a microfluidic system for rapid CE separations, produced at a low cost of less than a dollar each, using equipment and materials readily available in the ordinary laboratory. Applications of the system, after coupling to flow-injection and/or sequential-injection sample introduction, for the determination of FITC- labeled amino acids by laser-induced fluorescence, trace metals by chemiluminescence, carbohydrates by amperometry, and inorganic and organic anions by indirect UV absorbance are exemplified to illustrate the performance and versatility of the microfluidic system.