By Jacob on Friday, March 23, 2001 - 12:55 am:
Some of my colleagues increase the column flow
gradually when starting the HPLC-pump in order to
protect the column against sudden increases in the
pressure. For example 0-0.25-0.5-1 ml/min. I never
do that, but start the pump at 1 ml/min (in this
example) right away. Can gradual flow increase
significantly prolong column life time or not? Who
can tell me more about this?
By Kaf on Friday, March 23, 2001 - 02:07 am:
Certantly YES !! Is a way to protect the column.
By Anonymous on Friday, March 23, 2001 - 05:42 am:
Many modern HPLC systems have built in flow ramping capabilities to do exactly this. As well, some column type are much more fragile than others. Silica based C18 columns are quite rugged, and you probably do not increase the lifetime of these type columns by much do the gradual increase thing. On the other hand, some ion-exchange columns can be ruined by a single pressure spike.
By Uwe Neue on Friday, March 23, 2001 - 04:10 pm:
It depends on the type of column that you are dealing with. For columns prepared from a soft polymeric packing, it is better to increase the flow slowly. For hard packings such as silica-based packings, it does not make a difference. The compressibility of such a packing is virtually non-existant.
By Anonymous on Wednesday, March 28, 2001 - 11:35 pm:
Also, the system does not pressurize instantaneously, because there is always a "leak" (out through the column).
Seriously, has anyone ever published an actual comparison of column lifetime with and without "ramped" startup?
By Uwe Neue on Thursday, March 29, 2001 - 03:24 pm:
I doubt that you would find a publication on this. One can't even get publications on other issues of column lifetime, such as number of injections on a column etc. It's too boring for academia.
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