PRESSURIZED GRADIENT ELECTRO-HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A microbore liquid chromatographic system was developed for gradient elution using capillary columns with inner diameters of 50 and 100 mu m. In addition, voltage gradients up to 30 000 V can be applied across the length of the column. The dramatic improvement of reversed-phase separations of charged analytes is demonstrated by a separation of detritylated oligonucleotides on 5 mu m C-18 reversed-phase silica gel. Several examples are given, illustrating the influence of applied voltage gradients up to 400 V/cm upon the separation in both isocratic and gradient elution modes.