ABSTRACT
The ability of the modern analytical chemist to detect specific compounds at ng/g or lower levels in such complex matrices as natural waters or animal tissues is due in large part to the development of chromatographic methods. The science of chromatography began early in the twentieth century, with the Russian botanist Mikhail Tswett, who used a column packed with calcium carbonate to separate plant pigments. All chromatographic systems rely on the fact that a substance placed in contact with two immiscible phases, one moving and one stationary, will equilibrate between them. Different combinations of gaseous or liquid phases give rise to the types of chromatography used in analysis, namely gas chromatography, liquid chromatography, thin layer chromatography, and supercritical fluid chromatography. Chromatography has increased the utility of several types of spectroscopy by delivering separate components of a complex sample, one at a time, to the spectrometer.
