THE EFFECT OF ELECTROOSMOTIC AND HYDRODYNAMIC FLOW PROFILE SUPERPOSITION ON BAND BROADENING IN CAPILLARY ELECTROPHORESIS

The effect of the superposition of electroosmotic now and pressure-ind uced hydrodynamic counterflow on efficiency has been investigated for different capillary electrophoretic systems. Results are shown for 50 and 75 mu m internal diameter capillaries at several voltage and count erpressure levels. Hydrodynamic counterflows were successfully applied in electrokinetic chromatography in order to delay the entry of a UV- active pseudostationary phase, tetraphenyl porphyrintetrasulfonate, in to the detection zone allowing the separation of neutral nitroaromatic s. The separations are based on the weak charge-transfer interactions between the porphyrin and the analytes.