Cloning instrument preparation

There have been several approaches to overcome the traditionally slow SEC separations, which are caused by the diffusion processes in SEC columns. Most of them are column-related (see High-Speed SEC Columns, Small Particle Technology, and Smaller SEC Column Dimensions ) one utilizes the column void volume (cf. Overlaid Injections ), while another replaces separation with simplified sample preparation (see Flow Injection Analysis ). Cloning existing methods and instrumentation is also reviewed with respect to the potential time gain (see Cloning of SEC Systems ). Benefits and limitations of each method are summarized in Table 1. 

Instrumentational improvements are necessary for the use of microtechniques. For example, during gene cloning work only amounts of 1 to 50 ng of nucleic acids are sometimes available for preparation. This type of work requires special equipment which may be used for preparative as well as for analytical purposes on a microscale. 

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