Varian 3800 OQ
Posted: Wed Mar 21, 2012 6:33 pm
by ChemLane
I am having trouble performing an OQ on a Varian 3800 with a 1061 injector to a TCD detector. I have everything set up like the manual says, but my solvent peak(hexane) is tailing really bad and the C14, C15, and C16 peaks are eluting at the tail end of the solvent peak at a RT of ~3 min. I have messed with the flows a bit, but it hasn't helped much. I have previous years OQ chromatograms, but no method specs, and the peaks of interest have a RT of ~7 min. Anyone have any experience with this or have any ideas on flow settings?
Re: Varian 3800 OQ
Posted: Mon Apr 09, 2012 12:02 pm
by ykprakash
Measure reference flow and flow through column. They should be between 25 to 30 ml/min. Both should be same, say within 2 ml/min. Not so strict, but try your best. This ensures proper balance.
What's the det temp you are keeping ( say x) ? Filament temp should be x + 50. Recommended temp for det x= 250. Note that, it takes lot of time to heat and cool. This ensures proper filament current.
Find out max temp of installed column ( say Z) . Condition column overnight at z-30 degrees C. This should help revive column in case peak trailing is due to column.