Combination of Methods

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