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Gas Lines for LCMS
Posted: Mon Sep 17, 2012 7:25 pm
by DeniseHeinz
I'm working in a new company that is trying to do things on the inexpensive side. Has anyone used HDPE lines for their gas lines going to an LCMS. Would this cause any problems?
Re: Gas Lines for LCMS
Posted: Tue Sep 18, 2012 7:29 am
by Peter Apps
Two things would worry me; oxygen permeating into the nitrogen through the wall of the pipe, and plasticisers evaporating out of the polymer into the nitrogen.
Peter
Re: Gas Lines for LCMS
Posted: Thu Sep 20, 2012 3:03 pm
by lmh
A lot of systems use a short length of plastic tubing to link a nitrogen generator to an LC-MS, and obviously for Peter's reasons it has to be the right grade of tubing. If your company is thinking of avoiding having a proper wide-bore stainless-steel gas-line from a distant generator by running a verrrrry long piece of 1/4" tubing, you will find that there is a substantial pressure-drop along the tube at the flow-rates you need for conventional chromatography (as opposed to nano-columns) and it won't work. In a former lab that I used, we had a line that was about 12m from the generator, and we just about got away with it by doubling the tubing with a t-piece on each end. It was clumsy.