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to find the right solvent strength by rapid trial-and-error approach. Usually the right
solvent strength is determined by preliminary TLC separations of the sample of
interest. Solvent mixtures, particularly binary solvents are used more often than
pure solvents. There are several advantages to the use of binary solvents as for
example, solvents strength changes continuously with composition. The following
table shows the elutropic series of solvents:
Requirements of sample: The sample should be organic-soluble, of .1
intermediate molecular weight, and non-ionic. .2
Adsorption chromatography, particularly LSC is unique among other liquid
chromatographic methods in providing maximum differentiation among isomeric
mixtures. However, LSC is not noted for its ability to separate homologues, or
other mixtures differing in the extent of aliphatic substitution.
Partition chromatography .3
Liquid-liquid chromatography, which is sometimes called liquid-partition
chromatography. It involves one liquid as the moving phase (sometimes called the
carrier), while another liquid (the stationary phase) is usually dispensed onto a
finely divided inert support.
The liquid stationary phase is either immiscible with the moving phase, or it is
chemically bonded to the inert support. The process of partition chromatography is
similar to simple batch extraction between two immiscible liquids in a separating
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