| gel exclusion chromatography | <investigation> A lab technique, a type of column chromatography, used to separate the components of a mixture by molecular size and to collect the molecules which are larger than a certain size. It is similar to gel filtration, small molecules are slowed or trapped by the pores in the gel beads filling the column, while large molecules, too large to fit into the pores, slide past the beads and get to the bottom of the column first. at this point, the large molecules are collected. Gel exclusion refers to the maximum size of molecule which will fit into the gel bead pores, and this lab technique is used to collect the molecules in the mixture which are larger than, or excluded from, the pores. (09 Oct 1997) |
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| gel filtration chromatography | See: gel filtration. (05 Mar 2000) |
| partition chromatography | The separation of similar substances by repeated divisions between two immiscible liquids, so that the substances, in effect, cross the partition between the liquids in opposite directions; where one of the liquids is bound as a film on filter paper, the process is termed paper partition chromatography or paper chromatography. (05 Mar 2000) |
| reversed phase chromatography | A form of partitionary chromatography in which the stationary phase is more polar than the mobile phase. (05 Mar 2000) |
| chromatography | <investigation> Techniques for separating molecules based on differential absorption and elution. Term for separation methods involving flow of a fluid carrier over a nonmobile absorbing phase. (18 Nov 1997) |
| chromatography, affinity | A chromatographic technique that utilises the ability of biological molecules to bind to certain ligands specifically and reversibly. It is used in protein biochemistry. (12 Dec 1998) |
| chromatography, agarose | A method of gel filtration chromatography using agarose, the non-ionic component of agar, for the separation of compounds with molecular weights up to several million. (12 Dec 1998) |
| chromatography, deae-cellulose | A type of ion exchange chromatography using diethylaminoethyl cellulose (deae-cellulose) as a positively charged resin. (12 Dec 1998) |
| 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) |
| 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, 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) |