| chromatography, gas | Fractionation of a vaporised sample as a consequence of partition between a mobile gaseous phase and a stationary phase held in a column. Two types are gas-solid chromatography, where the fixed phase is a solid, and gas-liquid, in which the stationary phase is a nonvolatile liquid supported on an inert solid matrix. (12 Dec 1998) |
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| chromatography, gel | Chromatography on non-ionic gels without regard to the mechanism of solute discrimination. (12 Dec 1998) |
| chromatography, high pressure liquid | Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed. (12 Dec 1998) |
| chromatography, ion exchange | Separation technique in which the stationary phase consists of ion exchange resins. The resins contain loosely held small ions that easily exchange places with other small ions of like charge present in solutions washed over the resins. (12 Dec 1998) |
| chromatography, liquid | Chromatographic techniques in which the mobile phase is a liquid. (12 Dec 1998) |
| chromatography paper | Used in paper chromatography. Synonym: high quality filter paper. Congo red paper, paper impregnated with Congo red; used as a pH indicator, changing from blue-violet at 3.0 to red at 5.0. Filter paper, an unsized paper used in pharmacy and chemistry for filtering solutions; many varieties are used for paper chromatography. (05 Mar 2000) |
| chromatography, thin layer | Chromatography on thin layers of adsorbents rather than in columns. The adsorbent can be alumina, silica gel, silicates, charcoals, or cellulose. (12 Dec 1998) |
| column chromatography | A form of partition, adsorption, ion exchange, or affinity chromatography in which one phase is liquid (aqueous) flowing down a column packed with the second phase, a solid; the dissolved substances form a partition between the solid and liquid phases depending on the chemical and physical conditions of each phase; the more strongly adsorbed solutes reach the bottom of the column later than the less strongly adsorbed ones. (05 Mar 2000) |
| high-performance liquid chromatography | <investigation> A lab technique, a type of column chromatography, which uses a combination of several separation techniques to separate substances at higher resolution. Extremely sharp peaks on the elution profile can be produced with high-performance liquid chromatography (HPLC). (09 Oct 1997) |
| high-pressure liquid chromatography | <investigation> A lab technique, a type of column chromatography, which uses a combination of several separation techniques to separate substances at higher resolution. Extremely sharp peaks on the elution profile can be produced with high-performance liquid chromatography (HPLC). (09 Oct 1997) |
| ion exchange chromatography | <procedure> Separation of molecules by absorption and desorption from charged polymers. An important technique for protein purification. For small molecules the support is usually polystyrene, but for macromolecules, cellulose, acrylamide or agarose supports give less non-specific absorption and denaturation. Typical charged residues are CM carboxymethyl) or DEAE (diethylaminoethyl). (27 Oct 1998) |
| thin layer chromatography | <technique> Chromatography using a thin layer of powdered medium on an inert sheet to support the stationary phase. Faster than paper chromatography, gives higher resolution and requires smaller samples. (18 Nov 1997) |
| thin-layer chromatography | Chromatography through a thin layer of cellulose or similar inert material supported on a glass or plastic plate. (05 Mar 2000) |
| two-dimensional chromatography | Paper chromatography in which a spot, located originally in one corner of a sheet, is developed in one direction along one side of the sheet, after which the sheet is rotated 90 |
| liquid-liquid chromatography | Chromatography in which both the moving phase and the stationary (or reverse-moving) phase are liquids, as in countercurrent distribution. (05 Mar 2000) |