The miniaturization of analytical instrumentation has been a driving force in analytical chemistry for several decades. Miniaturization brings about many advantages for chemical analysis, including decreased analysis time, sample consumption, and reagent consumption; increased sample throughput; and the ability to analyze very small samples. Miniaturized analytical systems are less expensive to manufacture, and therefore cost less. An additional benefit of miniaturization is the ability to include more functions on a single device, with the objective of integrating a chemical laboratory on a chip (lab-on-a-chip). One outcome of lab-on-a-chip technology will be portable devices for point-of-care medical diagnostics, environmental monitoring, and the detection of chemical and biological warfare agents in real time.