Chromatography Forum

a person with the name "ChromaMaster" should not ask questions like that .
It does not matter how your column is attached. You are operating in a closed system under high pressure there is no way for liquid to go anywhere but in the direction of the flow (unless your system is leaking)

a person with the name "ChromaMaster" should not ask questions like that .
It does not matter how your column is attached. You are operating in a closed system under high pressure there is no way for liquid to go anywhere but in the direction of the flow (unless your system is leaking)

thanx for your answer

switching to vertical is more about reducing the instrument's footprint than anything else.

UPLCs which ten to use 150mm or less have gone back to horizontal column size no longer has an impact.

switching to vertical is more about reducing the instrument's footprint than anything else.

UPLCs which ten to use 150mm or less have gone back to horizontal column size no longer has an impact.

thanx alot but i still think that the gravity is playing a role for this issue. i think when you use a vertical direction the tailing factor is reduced quietly according to less gravity effect , but at horizontal direction the gravity and normal force maybe make a little bit distortion for analyte inside column .

thanx alot but i still think that the gravity is playing a role for this issue. i think when you use a vertical direction the tailing factor is reduced quietly according to less gravity effect , but at horizontal direction the gravity and normal force maybe make a little bit distortion for analyte inside column .

I'd want some data to back that assertion before repeating it in mixed company.

thanx alot but i still think that the gravity is playing a role for this issue.

So, do the experiment and try it both ways (my prediction is that you will not see a difference).

thanx alot but i still think that the gravity is playing a role for this issue.

So, do the experiment and try it both ways (my prediction is that you will not see a difference).

ChromaMaster, let us know about your results so we may nominate you to Ig Nobel Prize.

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just kidding, don't want to hurt anybody

just calculate gravity impact in this case vs. force pushing the solvent through the column. People using HPLC for decades and nobody ever considered this, why do you think nobody paid attention to this?

Seems like an interesting theory, I highly doubt that any effect that gravity might have on the analyte would effect in in such a way to reduce tailing. Wouldn't gravity have a constant effect on the front, middle and tail of the curve.

If you think gravity is affecting your system it sounds like you are using an HPLC for filtration rather than chromatography

gravity effect under around 100 atm pressure..this is like the gravity effect on the launching rocket..

Don't forget when the column is vertical then the theoretical plates stack better and are less likely to fall over and break.

If you have the column horizontal then the plates can separate and collect dust between them. This ruins your peak shape and the peak begin to lean over.

So always keep your column vertical and never let your LC ride on a merry-go-round as this really distorts the separations.

And by the way I no longer breathe helium in the lab anymore as it is now too expensive a habit to maintain. I prefer the Barry White effect of breathing Xenon much better.

Have a good weekend,

Rod

If the effect of gravity was via an effect on flow rate, then the effect could be most easily detected by comparing plate numbers and peak shapes with upward and downward flow in a vertically mounted column. I imagine that the differences might be quite small .

However, in a horizontal column gravity can have another effect. With a bit of help from poor packing, or packing dissolving to form a void at the column head, possibly with a bit of vibration, you could get a channel along the top of the packing that might well have more of an effect on performance than the nice symmetrical void that would form in a vertical column.

Peter