Gas Lines for LCMS

[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?

[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

[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.