Hydrophilic interaction capillary electrochromatography for the separation of polar compounds

The authors used hydrophillic interaction capillary electrochromatography (CEC) to separate polar compounds. Their system had a capillary column, packed with a hydrophillic, strong cation-exchange material of poly(2-sulfoethyl aspartamide)-silica and a hydrophobic mobile phase, which typically contained 80% acetonitrile. The elution order of polar compounds in hydrophilic interaction CEC is similar to that obtained by normal-phase chromatography, and the retention of solutes increases with their hydrophillicity. The authors obtained column efficiencies of 79,000-111,000 plates/m with separation of some model polar compounds under optimal conditions. The repeatability of their system was good with relative standard deviations of approximately 0.4% and less than 0.7% for void time and solute retention factors, respectively, in 10 consecutive runs