The development of two rapid scanning spectrometer systems for use as liquid chromatographic detector systems will be discussed. The first involves a minimum configuration involving a microprocessor and a linear photodiode array acting as a rapid scanning single beam UV/VIS detector. The instrument can monitor up to eight wave single-wave lengths. It plots the absorption at the selected wave lengths as a function of time on a standard X/Y plotter. It can take a complete spectrum about every five seconds — the time being limited mainly by the low slow speed of the recorder. The second system was designed around a large minicomputer system and is intended for pattern recognition work focusing on metabolite characterization, isolation, and identification. It is capable of taking 20 spectra/second in a dual-beam mode. Examples of the systems in practical applications will be shown, and a detailed analysis of the instruments design features will be presented.