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Column overloading in LC vs GC.
Posted: Mon Dec 03, 2012 8:44 pm
by lgchrom
I understand that column overloading on GC can affect resolution and can alter retention times. As long as this is not a problem for a determination , then it should not affect quantitation.
How about LC?
Re: Column overloading in LC vs GC.
Posted: Mon Dec 03, 2012 10:15 pm
by tom jupille
Depends on what kind of overload:
- Detector overload: the chromatography is OK, but you are out of the linear range of the detector. Resolution will probably look OK; peak shape may or may not look OK (if you totally saturate the detector you may "flat-top" the peak); quantitation will *definitely* be affected.
- Volume overload: the peaks will be wider than they should be because of the additional "extra-column" volume. Resolution will be impacted. Quantitation should be OK (aside from integration problems generated by the loss of resolution).
- Mass overload: retention time will decrease and the peak shape will suffer. Resolution will be impacted. Quantitation should be OK so long as you are not also overloading the detector and aside from integration problems due to resolution loss and/or tailing.
Re: Column overloading in LC vs GC.
Posted: Mon Dec 03, 2012 10:34 pm
by lgchrom
Thanks for your reply. I was talking about column overload. Not detector overload. So yeah basically it's the same as for GC?
Re: Column overloading in LC vs GC.
Posted: Tue Dec 04, 2012 3:41 pm
by tom jupille
Yes
Re: Column overloading in LC vs GC.
Posted: Thu Dec 06, 2012 1:25 am
by CLSgroup
You will also notice some peak fronting in some cases.
Re: Column overloading in LC vs GC.
Posted: Thu Dec 06, 2012 1:34 am
by tom jupille
Yes, but fronting is *much* less common than tailing. A "boy-scout-merit-badge-level" explanation of both is here:
viewtopic.php?f=31&t=18426
The fronting part is about 9 minutes in.