Compatibility of THF and dioxan with MS
Posted: Tue Mar 01, 2005 5:56 pm
Would any one explain me why organic modifiers such as THF and dioxan are not compatible with MS?
If you are doing ESI, you might not get good ionization in those solvents, unless they are mixed with something like an alcohol or water.
I have never used dioxane but have used THF with ESI-MS. With a compound dissolved in only THF, I got poor signal and very little ESI current. Adding isopropanol improved things.
The other consideration is that THF is said by some to be incompatible with PEEK tubing (not sure about dioxane). Some ion sources, such as those on the Sciex instruments, have a length of PEEK tubing as the LC flow path between the high-voltage ESI probe and a grounding union. Bypassing this tubing might cause a shock hazard, and replacing it with stainless steel would short your ESI needle to ground.
So in summary, I would not call these solvents incompatible, but be aware of the above issues.