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Ethanol peak in headspace runs
Posted: Wed Nov 05, 2014 5:51 am
by FJ Ram
Hi everyone, i've been having a problem in my residual solvents runs with headspace. I get a small height-variable peak at 3.4 min in every run, except in the blank, in which i drop solvent directly from the bottle to the vial. I've runned ethanol standards and they elute at that exact time, so i'm almost sure it's an ethanol ghost peak, how can i eliminate it? Can you help me?
Re: Ethanol peak in headspace runs
Posted: Wed Nov 05, 2014 3:26 pm
by AaronAIT
Are you using any solvents that contain EtOH as a stabiliser?
Re: Ethanol peak in headspace runs
Posted: Thu Nov 06, 2014 6:06 am
by FJ Ram
I don't think so, i'm using merck's dimethyl sulfoxide (and honeywell).
Re: Ethanol peak in headspace runs
Posted: Thu Nov 06, 2014 6:56 am
by kubowicz.tomasz
Hello
I'd recommend:
1.Run blank (empty, capped vial)
2.Run your std (lowest concentration)
3.Run blank again (empty, capped vial)
If you have no peaks for blanks it means that your problem is not related to hardware. You should try different solvent or check all steps for sample preparation (pipettes, volumetric flask etc)
Regards
Tomasz Kubowicz
Re: Ethanol peak in headspace runs
Posted: Fri Nov 07, 2014 4:50 am
by FJ Ram
Thank you thomasz! I'll run that tests on weekend!
Also, do you think i need glass labware exclusively to GC, restricted from HPLC analysis? And what's the best way i can wash it?
Re: Ethanol peak in headspace runs
Posted: Fri Nov 07, 2014 3:10 pm
by KM-USA
Also, do you think i need glass labware exclusively to GC, restricted from HPLC analysis? And what's the best way i can wash it?
No, don't think you need dedicated glassware. Be sure to dry completely though, make sure no condensate remains in volumetric flask necks.