Chromatography Forum

Hello UHPLC/HPLC Users,

We've heard from some customers that they are not getting the lifetime they'd like in terms of number of injections, when operated at high pressures (> = 600 bar) on several different competitive brands of UHPLC columns (~100-400 injections).

Out of curiosity, approximately how many injections do you get or have you gotten, on average, (assuming no pressure limitations from protein precipitation, particulates, filtered samples and standards) when you operate at higher pressure than 500-600 bar (~7200-8700 psi)?

How many injections is too few to be acceptable?


Thanks very much,

Tom

Thomas J. Waeghe, Ph.D.
Senior Scientist
MAC-MOD Analytical, Inc.
103 Commons Court
Chadds Ford, PA  19317
twaeghe@mac-mod.com
610-358-9696

Assuming that all used column brands are made from mechanically stable silica, then high pressure should be not a problem.
Assuming that all used column brands showed an optimum of packing density, then high pressure should be not a problem.

1 injection is not acceptable.
5000 injections are also not acceptable, but some customers get to that level.

It all depends on the sample, the complexibility of the sample mixture and many other factors.
If a method is established and 500 injections are reached with several columns I would be only concerned if suddenly I get only 50 injections.