Extracolumn band broadening column efficiency with

It is clear from Equation (20) that peak volumes are directly proportional to the volume of the column and that samples elute with smaller peak volumes from the same column when filled with a more efficient, that is, smaller size, packing material. The more efficient the column, the narrower are the sample bands and the more important is the effect of extracolumn band broadening. Wider columns provide for more peak volume, and this reduces the importance of extracolumn band broadening. 

Column Efficiency with Extracolumn Band Broadening... 

These trends toward the use of shorter columns with narrower diameter mean that the overall volume of today s UHPLC columns can be much smaller than the HPLC columns of the past. Consequently, the extra-column band-broadening effect on efficiency can become especially significant in UHPLC as the effect is closely related to column dimensions (14,15). Recently, extra-column band-broadening has been extensively investigated in UHPLC (16-19), conventional HPLC (20), capillary HPLC (21), and modified convenfional HPLC (22). Additionally, the effects of extracolumn volume on other chromatographic parameters including retention factor, selectivity, and pressure drop also become more significant in UHPLC. 

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