Chiral Stationary Phases and Chiral Coated Phases

Few chiral phases are used in TLC; one of the main reasons for this is that chiral stationary phases with very high UV background can only be used only with fluorescent or coloured solutes. For example, amino-modified ready-to-use layers bonded or coated with Pirkle-type selectors, such as N-(3,5-dinitrobenzoyl)-l-leucine or R( — )-a-phenylglycine, are pale yellow and strongly adsorb UV light. Another reason is the high price of most CSPs.

The most widely used CSPs or CCPs are polysac-charides and their derivatives and silanized silica gel impregnated with an optically active copper (ii) complex of derivatized hydroxyproline. The use of silica gel impregnated with chiral polar selectors, such as d-galacturonic acid, ( + )-tartaric acid, (—)-brucine, l-aspartic acid or a complex of copper (ii) with l-proline, should also be mentioned.

In CSPs, owing to the nature of the polymeric structure, the simultaneous participation of several chiral sites or several polymeric chains is conceivable. In CCPs, the chiral sites are distributed at the surface or in the network of the achiral matrix relatively far away from each other and only a bimolecular interaction is generally possible with the optical antipodes to be separated.

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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