Chromatography is a separations method that relies on differences in partitioning behavior between a flowing mobile phase and a stationary phase to separate the the components in a mixture.
A column (or other support for TLC, see below) holds the stationary phase and the mobile phase carries the sample through it. Sample components that partition strongly into the stationary phase spend a greater amount of time in the column and are separated from components that stay predominantly in the mobile phase and pass through the column faster.
Gas chromatography is a method for separating the components of a solution and measuring their relative quantities. It is a useful technique for chemicals that do not decompose at high temperatures and when a very small quantity of sample (micrograms) is available. The use of gas chromatography is limited by the decomposition temperature of the components of the mixture and the composition of the column. Most columns cannot withstand temperatures greater than 250-350 °C.
Chromatography is a versatile technique used to separate compounds in a mixture. It relies on differences in interaction of molecules with a solvent system (the mobile phase) and a solid or gel known as the stationary phase.
Research with thin-layer and column chromatography showed that separations are much more effective when the stationary phase is a very thin layer on the surface of very small and very uniform spherical beads. However, resistance to flow of the mobile phase is very much higher, and in order to get a useful flow of a liquid mobile phase, e. g., 1 - 3 milliliters/minute, pressures of around 15 Mpa (about 2,000 psi) must be applied to the mobile phase.
Chromatography is a sophisticated method of separating mixtures of two or more compounds. The separation is accomplished by the distribution of the mixture between two phases: one that is stationary and one that is moving. Chromatography works on the principle that different compounds will have different solubilities and adsorption to the two phases between which they are to be partitioned.
An easy-to-understand explanation of how chromatography works, the different types, and what they're used for.
Angela Stubbs's insight:
Most of us have got our papers wet at some time or another, but have you ever noticed what happens to the ink as the water spreads? It doesn't always smudge and blur, as you might expect. Sometimes it splits up into weird colored streaks that creep across the page. When that happens, you're seeing chromatography in action.
Chromatography is the science of separating mixtures from complex to simple. It is a collective term for a set of laboratory techniques as well as equipments used by scientists. Chromatography techniques are either preparative or analytical.
An introduction to chromatography using thin layer chromatography as an example. Even if you aren't interested in thin layer chromatography directly, it would still pay you to read this page first before going on to the one(s) you are interested in.