Search results
Results From The WOW.Com Content Network
The introduction of paper chromatography was an important analytical technique which gave rise to thin-layer chromatography. [13] Finally, gas-liquid chromatography, a fundamental technique in modern analytical chemistry, was described by Martin with coauthors A. T. James and G. Howard Smith in 1952. [14]
Chromatography is based on the concept of partition coefficient. Any solute partitions between two immiscible solvents. When one make one solvent immobile (by adsorption on a solid support matrix) and another mobile it results in most common applications of chromatography.
Adsorption removes a soluble impurity from a feed stream by trapping it on the surface of a solid material, such as activated carbon, that forms strong non-covalent chemical bonds with the impurity. Chromatography employs continuous adsorption and desorption on a packed bed of a solid to purify multiple components of a single feed stream. In a ...
A corresponding partition coefficient for ionizable compounds, abbreviated log P I, is derived for cases where there are dominant ionized forms of the molecule, such that one must consider partition of all forms, ionized and un-ionized, between the two phases (as well as the interaction of the two equilibria, partition and ionization).
Gas chromatography (GC) is a common type of chromatography used in analytical chemistry for separating and analyzing compounds that can be vaporized without decomposition. Typical uses of GC include testing the purity of a particular substance, or separating the different components of a mixture. [ 1 ]
Brunauer, Emmett and Teller's model of multilayer adsorption is a random distribution of molecules on the material surface. Adsorption is the adhesion [1] of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. [2] This process creates a film of the adsorbate on the surface of the adsorbent.
This is a different process from adsorption, since molecules undergoing absorption are taken up by the volume, not by the surface (as in the case for adsorption). A more common definition is that "Absorption is a chemical or physical phenomenon in which the molecules, atoms and ions of the substance getting absorbed enter into the bulk phase ...
Reversed-phase liquid chromatography (RP-LC) is a mode of liquid chromatography in which non-polar stationary phase and polar mobile phases are used for the separation of organic compounds. [ 1 ] [ 2 ] [ 3 ] The vast majority of separations and analyses using high-performance liquid chromatography (HPLC) in recent years are done using the ...