Parallel segmented flow chromatography columns: Conventional analytical scale column formats presenting as a ‘virtual’ narrow bore column

Narrow bore columns find advantage in HPLC applications when volumetric flow is important, For example, for detection processes that are volume limited. Yet there are significant drawbacks to narrow bore columns. Due to their small column volume relative to analytical scale columns, narrow bore columns are more affected by system dead volume. In addition the wall effect and the variation in packing density from the centre to the wall are more significant in these columns relative to larger scale analytical columns. In this study we operate a 4.6 mm i.d. parallel segmented flow column in such a manner that it emulates 2.1 mm i.d. and 3.0 mm i.d. columns. By using a parallel segmented flow column in this way, it was possible to combine the benefits of narrow bore and analytical scale columns.

► The radial central flow stream is separated from the wall flow stream.
► Efficiency is higher when flow is collected from the central stream.
► Sensitivity is higher when flow is collected from the central section and detected.
► A ‘virtual’ column with an i.d. proportional to the % of flow from the centre.
► This virtual column does not suffer from wall effects.