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The greater the separation factor value is over 1.0, the better the separation, until about 2.0 beyond which an HPLC method is probably not needed for separation. Resolution equations relate the three factors such that high efficiency and separation factors improve the resolution of component peaks in an HPLC separation.
The separation is based on the differential partitioning between the mobile and the stationary phases. Subtle differences in a compound's partition coefficient result in differential retention on the stationary phase and thus affect the separation. [1] Chromatography may be preparative or analytical.
It is a common observation that when oil and water are poured into the same container, they separate into two phases or layers, because they are immiscible.In general, aqueous (or water-based) solutions, being polar, are immiscible with non-polar organic solvents (cooking oil, chloroform, toluene, hexane etc.) and form a two-phase system.
This work was published in 1941 as "a new form of chromatogram employing two liquid phases." [8] The article describes both the theory in terms of the partition coefficient of a compound, and the application of the process to the separation of amino acids on a water-impregnated silica column eluted with a water:chloroform:n-butanol solvent mixture.
Ion chromatography (or ion-exchange chromatography) is a form of chromatography that separates ions and ionizable polar molecules based on their affinity to the ion exchanger. [1] It works on almost any kind of charged molecule —including small inorganic anions, [ 2 ] large proteins , [ 3 ] small nucleotides , [ 4 ] and amino acids .
In liquid chromatography, the mobile phase velocity is taken as the exit velocity, that is, the ratio of the flow rate in ml/second to the cross-sectional area of the ‘column-exit flow path.’ For a packed column, the cross-sectional area of the column exit flow path is usually taken as 0.6 times the cross-sectional area of the column.
Weak affinity chromatography [29] (WAC) is an affinity chromatography technique for affinity screening in drug development. [ 30 ] [ 31 ] WAC is an affinity-based liquid chromatographic technique that separates chemical compounds based on their different weak affinities to an immobilized target.
A separation process is a method that converts a mixture or a solution of chemical substances into two or more distinct product mixtures, [1] a scientific process of separating two or more substances in order to obtain purity. At least one product mixture from the separation is enriched in one or more of the source mixture's constituents.