[Research on the reproducibility and selection of experimental conditions of capillary electrochromatography]

In this work, we prepared the packed columns for capillary electrochromatography (CEC) with 75microm and 100microm i.d., both of coupled mode and uncoupled mode. A mixture of thiourea and other three aromatic compounds was employed to evaluate the efficiency of the CEC columns. RSD values of retention times smaller than 2.12% was obtained on the home-made CEC system. The influence of pH value and the concentration of the organic solvent in the buffer on the retention behavior was investigated, giving a guide to the selection of experimental conditions. High speed analysis can be achieved by using high pH value buffers. Higher concentration of acetonitrile will improve the elution ability, while lower ocncentration of acetonitrile would improve the resolution. Seven kinds of neutral molecules were separated efficiently within 25 minutes. The results from the two modes of CEC columns were compared.