The effect of column packing procedure on column end efficiency and on bed heterogeneity - Experiments with flow-reversal.

Affiliation

Department of Analytical and Environmental Chemistry and Szentágothai Research Center, Ifjúság útja 6, H-7624 Pécs, Hungary; MTA-PTE Molecular Interactions in Separation Science Research Group, Ifjúság útja 6, H-7624 Pécs, Hungary; Institute of Bioanalysis, Medical School, University of Pécs, Szigeti út 12, H-7624 Pécs, Hungary. Electronic address: [Email]

Abstract

The effect of column end structure and bed heterogeneity of six commercially available reversed-phase chromatographic columns for fast liquid chromatography with different column packing materials - such as fully porous (Waters XBridge C18 with 1.7 μm particles) and superficially porous (Waters CORTECS C18 with 1.6 μm particles), with column dimension of 2.1 × 50, 100 or 150 mm were tested with flow-reversal method. The method includes arresting the flow when a non-retained marker (thiourea) has penetrated to a given distance into the column and then reversing the column. Hence, when the flow has been restarted, the sample is eluted at the same end of the column where it entered. The experiments showed that all columns are axially heterogeneous, and some differences could be observed between the two respective column ends. Furthermore, we can conclude that the shorter columns are axially more homogeneous than the longer ones, thus the column length is an influencing factor on the column packing procedure.

Keywords

Column packing,Flow-reversal,Packed bed heterogeneity,Sub-2-μm particles,UHPLC,

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