Liquid chromatography, general considerations

High Pressure Liquid Chromatography. This modem version of the classical column chromatography technique is also used successfully for separation and quantitative analysis of dyes. It is generally faster than thin-layer or paper chromatography however, it requires considerably more expensive equipment. Visible and uv photometers or spectrophotometers are used to quantify the amounts of substances present. 

At present moment, no generally feasible method exists for the large-scale production of optically pure products. Although for the separation of virtually every racemic mixture an analytical method is available (gas chromatography, liquid chromatography or capillary electrophoresis), this is not the case for the separation of racemic mixtures on an industrial scale. The most widely applied method for the separation of racemic mixtures is diastereomeric salt crystallization [1]. However, this usually requires many steps, making the process complicated and inducing considerable losses of valuable product. In order to avoid the problems associated with diastereomeric salt crystallization, membrane-based processes may be considered as a viable alternative. 

Taking the above considerations into account Nikolov proposed a general model to describe retention in gas-liquid chromatography given by equation (2.1)... 

High-Performance Liquid Chromatography 7.2.2.1 General Considerations 7.2.2.1.1 Historical... 

The primary focus of this chapter in on general approaches and considerations toward development of high-performance liquid chromatography (HPLC) methods for separation of pharmaceutical compounds, which may be applied within the various functions in the drug development continuum. It is very important to understand the aim of analysis and the requirements for a particular method to be developed. The aim of analysis of each HPLC method may vary for each developmental area in the drug development process and specific examples are given in Section 8.2. 

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