Column radial homogeneity in high-performance liquid chromatography

The radial distribution of analyte molecules within an elution band in HPLC was determined by local, on-column, fluorescence detection at the column outlet. Several optical fiber assemblies were implanted in the exit frit at different points over the column cross-section and the fluorescence of a laser-dye analyte was measured. The individual elements of a diode array were used as independent detectors. The distribution of the mobile phase velocity across the column was measured for a number of standard size analytical HPLC columns of different efficiencies, operated at different mobile phase linear velocities. The dependence of the column efficiency on these profiles is discussed.