Combination of Methods

Abstract

It is sometimes possible to obtain pure compounds after a single chromatographic step (e.g. preparative LC; Hostettmann et al. 1977 or RLCC ; Schübel and Stöckigt 1984) but more often than not, a combination of methods is required. This fact becomes self-explanatory when one considers, for example, that the isolation of natural products from plant sources may involve the search for one compound out of an extract containing several thousand components. Of course, the particular separation problem depends on the discipline involved — obtention of a product from a synthetic reaction step may require the separation of only one by-product. As far as such relatively problem-free separations are concerned, however, other less expensive and less time-consuming techniques (crystallisation etc.) would be of first priority.