By which I mean not reverse flow, but can I position the column inlet on the bottom and run sample into it so that the sample travels upward against gravity? Will that broaden my peaks or have other deleterious effects on the chromatograph? Our HPLC pump/detector was positioned with the detector on top, but I think that this factory setup is not typically used with SEC columns. Thanks everybody in advance for your thoughts on this.
Yes if you are using a prepacked column. Only don't exceed the max flow rate. Probably i'll see some pressure lowering: that's normal! Bye
The packing will need a little extra time to equilibrate, as any void space will accumulate at the inverted column head (while flow is maintained) but may tend to settle, under gravity, so that it returns to the highest point when there is no flow.
Hi Zoe,
Do you mean that the flow strength will create a void at the inverted column head (meaning the head on the bottom, the inlet), and that the packing will resettle at the bottom when the flow is turned off? Does this mean that we should avoid higher (or "normal") column pressures/flow rates?
Thanks!
Off course, i saw several SEC systems with columns mounted in a vertical column oven. In case of multiple columns, one is directed upward, next downward and so on. Unless your pump is producing reliable flow, it should not be any problem
No, the flow rate (within the limits for the column) would not CREATE a void but, over time, there is a tendency for any void space (between the packing material particles) to gradually accumulate at the head of the column. Since you are proposing to run your column 'inverted', if any void space exists in your column, it will tend to accumulate at the column 'head' when under pressure. However, without any flow to oppose gravitational effects, the packing would tend to re-settle with the void at the highest point. If no void exists (eg: if this is a new, pre-packed HPLC column) then there will be no observable difference at all. Even if there is a significant void space, the column head can either be carefully filled with compatible packing material beads to reduce it, or just allow a little extra equilibration time for the packing material to re-distribute before use, then maintain a constant flow/pressure during your separation.
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