The history and development of preparative HPLC

Chromatography can be defined as the separation of mixtures by distribution between two or more immiscible phases. Some of these immiscible phases can be gas-liquid, gas-solid, liquid-liquid, liquid-solid, gas-liquid-solid and liquid-liquid-solid. Strictly speaking, a simple liquid-liquid extraction is in fact a chromatographic process. Similarly, distillation is a chromatographic process that involves separation of liquids by condensation of their respective vapours at different points in a column. 

Chromatography was originally developed to isolate coloured pigments from plants. Hence, from Greek origins we get chromato, colour and graph, to record . 

Fortunately for us, some very clever scientists have seen the wood for the trees and have taken these simple observations and developed them into complex, highly efficient, methods of purification. 

The first column based separations performed in a true industrial setting can be better demonstrated by the purification of petroleum on Fuller s earth in the 1920s. The 1950s marked the development of simulated moving bed (SMB) chromatography for the separation of sucrose and fructose in the sugar industry. However, these separations are limited low to medium pressure 

Various distribution plates have been designed using anything from simple engineering logict 3,14,15] to computational fluid dynamics (CFD)l16l Layouts vary from complex multilayered plates 171 to single discs, but the most common approach 

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At an early stage in the history of combinatorial synthesis it was apparent that product purity in excess of 80 % is not always attainable. In fact, purities of 30-40 % are quite common for several types of reaction. However, especially for single compounds from compound collections, high-throughput purification systems using HPLC have been developed. The degree of purity is first ascertained by analytical HPLC, and products having a purity below a pre-set threshold are subjected to this fully automated sample purification on a semipreparative or preparative scale. In first technical approaches, samples were... 

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