Microchip analysis has become an attractive option in CE for clinical applications, not only because these kinds of analysis require usage of complex samples that are often limited in quantity but also because this system could allow clinicians to make quicker treatment and drug therapy decisions.
The use of CE in the microchip format allows high-speed separations of very small samples, and multiple channel systems have great potential for high-throughput analysis. The first report of DNA separation on a microchip device was published by Woolley and Mathies in 1994 (103). Since then, great progress has been made in the design of these devices, going from single-channel to multiple-channel chips, allowing analysis of several DNA samples.
The design of these systems was reviewed by Gao et al. in 2001 (104). A typical microchip device consists of one or several separation channels of 3–10 cm in length and 10–100 μm in diameter. There are also buffer, waste, and sample reservoirs. High voltages of 2–30 kV can be applied to the reservoirs by platinum electrodes because these systems disperse the heat very efficiently.
The small samples used in the CE microchips require extremely sensitive detection techniques. LIF is the most commonly used detection method in CE microchips, although electrochemical, ultraviolet (UV), chemiluminiscence, and indirect fluorescence detection methods have been combined with these systems.
