Radial distribution of the contributions to band broadening of a silica-based semi-preparative monolithic column

摘要

Using an on-column local electrochemical microdetector operated in the ampero_metric mode, band elution profiles were recorded at different radial locations at the exit of a 10 mm id, 100 mm long silica-based monolithic column. HETP plots were then acquired at each of these locations, and all these results were fitted to the Knox equation. This provided a spatial distribution of the values of the eddy diffu_sion (A), the molecular diffusion (B), and the resistance to the kinetics of mass trans_fer (C) terms. Results obtained indicate that the wall region yields higher A values and smaller C values than the central core region. Significant radial fluctuations of these contributions to band broadening occur throughout the exit column cross-sec_tion. This phenomenon is due to the structural radial heterogeneity of the column.