Flow counterbalanced capillary electrophoresis using packed capillary columns: resolution of enantiomers and isotopomers.

A method with the ability to increase greatly both the resolution and efficiency of a given capillary electrophoretic system is described. This method differs from traditional capillary electrophoresis (CE) in that a counterflow is induced in the direction opposite to the electrokinetic migration of the analyte. This has the effect of extending not only the time the analytes migrate in the electric field but also the effective length and the effective applied voltage of the system.

Investigation of electrospray ionization and electrostatic focusing devices using a three-dimensional electrospray current density profiler.

A novel instrument for profiling the current density of nanoelectrospray ionization plumes in three dimensions has been developed. A hemispherically-shaped electrostatic lens at atmospheric pressure is found to be able to compress the space-charge in nano-ESI and increase the average current density in the plume to three times the nominal value. Ion transmission into a single-quadrupole mass spectrometer is found to roughly double using the electrostatic lens.