Ultrahigh-voltage capillary zone electrophoresis

An ultrahigh-voltage capillary electrophoresis system was built to demonstrate the possibility of extending the applied potential and thus the separation power of capillary electrophoresis, A commercial 30-kV power supply was extensively modified in order to provide electrical potentials up to 120 kV, A unique electrical shielding system was developed to prevent capillary breakdown and corona or spark discharges. Electrophoretic Studies using a mixture of peptide standards, as well as a complex mixture of peptides obtained from a protein digest, showed that the numbers of theoretical plates achieved increase linearly with applied voltage, Theoretical plate counts ranging from 2.7 to 6.1 million plates were obtained for peptides in a separation done at 120 kV, Resolution also increased with the square root of applied voltage, as predicted by theory.