View your list of saved words. (You can log in using Facebook.)
Definition of CHROMATOGRAPHY
: a process in which a chemical mixture carried by a liquid or gas is separated into components as a result of differential distribution of the solutes as they flow around or over a stationary liquid or solid phase
Method first described in 1901 by Mikhail S. Tsvet for separating mixed chemical substances. Tsvet's neglected work, rediscovered in the 1930s, uses the different affinities of substances in a solution in a mobile phase (a moving stream of gas or liquid) for adsorption onto a stationary phase (a fine-grained solid, a sheet of filtering material, or a thin film of a liquid on a solid surface). Choices of materials for these phases allow enormous versatility for separating substances including biological fluids (e.g., amino acids, steroids, carbohydrates, pigments), chemical mixtures, and forensic samples. In the original technique, an organic solvent flowed through a column of powdered alumina (seealuminum), sodium carbonate, or even powdered sugar to separate mixed plant pigments. Among current adaptations are paper chromatography (PC), thin-layer chromatography (TLC), liquid chromatography (LC, including high-performance liquid chromatography, or HPLC), and gas chromatography (GC). Some remain laboratory techniques, but others (especially HPLC) can be used on an industrial scale. They require different methods for detecting and identifying the separated components, including colorimetry, spectrophotometry, mass spectrometry, and measurement of fluorescence, ionization potential, or thermal conductivity. A.J.P. Martin shared a 1952 Nobel Prize for developing LC and PC, and in his Nobel lecture announced the development (with his cowinner R.L.M. Synge and other colleagues) of GC.