Cellulose Derivatives

Among derivatized polysaccharides, cellulose triacetate (CTA) is the most used stationary phase for the resolution of racemic compounds by TLC.

The different fit of the two enantiomers into the laminae of the polymer leads to separation of the optical antipodes which is mainly governed by the shape of the solutes (flat molecules showing a better permeation into the cavities) and only to a minor extent by electrostatic interactions involving the functional groups of the molecules. Hence the name 'inclusion chromatography'. In addition, the chiral recognition of CTA depends strongly on its structure and the type of eluent and increases as the crystallinity of the polysaccharide is increased. Microcrystalline cellulose triacetate (MCTA) can be prepared from microcrystalline cellulose with almost complete preservation of microcrystallinity. Usually, the type of eluent and its composition are important for chiral recognition because these produce different swelling of MCTA, which in turns enables the separation of solutes of different sizes and characteristics.

The use of w-hexane-isopropanol mixtures resulted in unsatisfactory separations since extremely elongated spots are generally obtained. Aqueous-alcoholic solutions have the opposite effect, giving rise to round and compact spots.

This CSP is able to resolve a broad range of structurally different racemates. In general, more polar molecules require a higher percentage of water than hydrophobic compounds.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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