Page 109 - phytochemistry general program

Fractional crystallization is a method of refining substances based on differences
in solubility. It depends on the differences in solubility of the components of a
mixture in a particular solvent. Derivatives of the particular components are

sometimes employed.

Chromatography .5

Chromatography is the collective term for a set of laboratory techniques for the
separation of mixtures. Its wide applications and clean separation revolutionized
research in the area of phytochemistry. Advances in experimental methods now

occur very quickly and noticeable in almost all areas of chromatography.

Advantages of chromatography .1

As a separation technique, chromatography has several advantages over other .2
methods. Some of these advantages are summarized in the following: .3
.4
Chromatography is almost the only technique which can give 100% pure isolates. .5
Different members of each chemical group can be easily separated even

homologues.

It can be used on an analytical as well as micro- or macro- preparative scales.
Analytical as well as preparative applications are available.

Applicable to almost all chemical compounds: organic, inorganic and even
biomolecules can be handled by chromatography.

One of the most important advantages of chromatography, particularly in the area
of natural products chemistry, is that substances are separated unchanged.

Some chromatographic techniques can be joined with other analytical methods
which lead to more integrated results e.g. GC-MS. 6- Chromatographic techniques

range from simple manual assemblies to highly sophisticated ones.

Discovery of chromatography

Chromatography is a physicochemical method for separation of complex mixtures
was discovered at the very beginning of the twentieth century by Russian–Italian
botanist M. S. Tswett. In 1903, he gave a very detailed description of the newly

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