Chromatography Forum

Hello, I'm planning on installing 3-way ball valves just upstream of my GC-MS carrier gas inlets to allow for toggling between helium and nitrogen. Swagelok valves typically come pre-lubricated, though they do make a special non-lubricated version of all of their ball valves which is more expensive and has lower pressure ratings. I don't know if the silicone-based lubricant on their "normal" valve assemblies is something to worry about or not. Agilent technicians I spoke to did not seem to be aware there are versions with and without lubrication and defaulted to recommending the non-lubricated version because obviously, lubricants could be a source of contamination. Does anyone have any real-world experience with this?

I have been using them to switch between helium and hydrogen on my 7000C MSMS and have not see any noticeable contamination. I used the ones sold by Restek https://www.restek.com/en/products/acce ... ves/46983/

These are the 3-way valves, so one out to the EPC and one in each from Helium and Hydrogen. Not sure if they are the lubricated ones or not. If there is any problem with contamination you could put a hydrocarbon trap after the valve and before the EPC just in case.