Problems and achievements in the instrumentation and column technology for chromatography and capillary electrophoresis

Summary

Chromatographic and electrophoretic separation methods are compared with regard to miniaturization in capillaries (“open tubular columns”) and with emphasis on the analytical applicability of such techniques. Instrumental problems of detection and sample introduction which are related to the very low sample capacity of capillary systems are discussed together with the procedures for polymeric coating of capillary surfaces as well as porous, small-particle support materials. Surface coatings are also important in capillary electrophoresis in order to control electroosmotic flow and to suppress adsorptivity for analyte molecules. In the micellar electrokinetic chromatography mode of electrophoresis neutral small molecules can also be separated with advantage. Micropacked columns cause less instrumental problems in SFC and LC because of their higher sample capacity. In CGE using polyacrylamide gel-filled capillaries excellent separations of charged, large biomolecules, especially oligonucleotides, can be achieved.