Electrokinetic reversed-phase chromatography with packed capillaries

Possibilities and limitations for the applicability of electroendosmotic flow as an elution system in reversed-phase chromatography with packed capillaries were investigated. By using electroendosmotic elution, very high performance could be achieved. No loss of column efficiency was observed up to linear electroendosmotic flows of ca. 3 mm/s. With 50-μm I.D. fused-silica capillaries, packed with 3-μm ODS, reduced plate heights of 1.7–2.2 were obtained for test compounds (k′ = 0–4.8) at a linear velocity of 2.6 mm/s. Electroendosmotic elution systems allowed the use of very small-particle packing materials. With 1.6-μm Monospher ODS, an extremely high chromatographic efficiency of up to 790 theoretical plate/s was obtained.