Formation of Diastereomers by Using a Pre Column Derivatization

In this method, the racemate is reacted with an optically pure compound leading to formation of diastereomers. Owing to their different physioco-chemical properties, diastereomers can be resolved by using classical achiral mobile and stationary phases. This method can only be applied to molecules bearing reactive functions such as amines, acids and alcohols. For preparative purposes, partial racemization can occur when recovering the initial enantiomer. This problem represents the major limitation of this method. Moreover, this method has some disadvantages: (1) the chiral reagent must be optically pure, or its optical purity has to be well known (otherwise, poor accuracy will be achieved); (2) the derivatizing reaction must be quick and quantitative; and (3) the chromatographic behaviour of the derived dia-stereomers should be suitable (easy separation, good stability under the chromatographic conditions, ease of recovery with absence of racemization during the step leading to the initial enantiomers).

This was the method of choice before the development of chiral stationary phases (CSPs). It is still applied, but usually in order to improve detection limits. The method is not commonly used with SFC although (S)-trolox methyl ether has been used to derivatize chiral alcohols for attempted separation by GC and SFC with achiral systems. Using this derivatizing method, several compounds were successfully resolved by SFC but GC failed because of thermal decomposition of the ester derivatives.

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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