Development of new methods for miniaturized separation techniques

Abstract: The aim of this study has been to develop and investigate separation methods for miniaturized systems. Micro liquid chromatography was coupled on-line with a mass spectrometer equipped with an electrospray ionization source for the separation and characterization of flavonoids in Citrus juices. Capillary electrophoresis was utilized for the separation of four different types of fatty acid isomers. In the micellar electrokinetic chromatography mode the performance of a number of buffer systems with different additives was examined. For the composition of the basic buffers ingredients multivariate methods were employed. In order to improve electrophoretic separations of analytes that easily adsorb onto the capillary wall, e.g. proteins, a new coating method was developed.The coated capillaries were tested for a broad range of applications and a new method for fingerprinting peptide digest of a bacterial protein was developed.The main conclusions are that miniaturized systems offer a lot of benefits due to extremely low volume requirement of buffer components as well as samples. These advantages make it possible to use more expensive buffer ingredients and lower the consumption of solvents dramatically. Low sample consumption is desirable in a lot of areas e.g. in the field of analytical biotechnology. Moreover, separation and detection parameters were improved in miniaturized systems.