Capillary electrochromatography (CEC) of polar compounds: towards an improved understanding of fundamentals of retention and separation efficiency

Capillary electrochromatography (CEC) has focused complementary fields of research in recent times, since it combines the best features of high-performance liquid chromatography and capillary electrophoresis techniques. Therefore, CEC enables researchers to separate minute sample concentrations. However, the preparation and characterisation of robust capillary columns is vital to ensure high separation resolution and efficiency. This project involved the preparation and characterisation of three different types of chiral capillary columns, two of them were porous layer open tubular (PLOT) columns and the other involved a monolithic stationary phase made by coating or filling fused silica capillaries with immobilised polymers and using chiral compounds or chiral selectors to modify the new stationary phases. Furthermore, a number of optically active analytes including amino acids were analysed using the prepared columns with acetonitrile used as a mobile phase modifier with buffers of different acidity levels and concentrations to optimise the separation conditions. Comparison between the performance of these PLOT and monolithic columns was anticipated to provide a valuable contribution to the selection of the best technique that could be utilised to separate enantiomers including racemic amino acid mixtures.