Chromatography Forum

Hi All,

We have a LC-QTOF MS system (Agilent 6520). The most common sample solvent we use is 80/20 methanol/IPA mix. There are times that a different solvent is needed due to sample solubility issues, but we're not sure if these solvents are safe to use in the MS system. The two solvents we like to attempt are THF and 0.1 N HCl. Will these solvents cause issues in the performance of the MS? Your opinion is appreciated.

THF----swells/degrades any PEEK tubing on HPLC

0.1N HCl----very bad for stainless steel; can always rinse out LC after use. BUT think about HCl vapour in pumps etc.

Thanks for your reply, JMB. We're not trying to use THF and 0.1 N HCL in the mobile phase. We use these solvents as diluent for the samples and the injection volume is usually 1 uL.

Thanks for your reply, JMB. We're not trying to use THF and 0.1 N HCL in the mobile phase. We use these solvents as diluent for the samples and the injection volume is usually 1 uL.

As long as you rinse the needle after use it should be ok, The Agilent autosamplers have the option of a needle rinse where it dips the needle into a vial of solvent before injection, this should rinse any HCl off the outside of the needle if you use DI Water as the rinse. Otherwise I wouldn't think 1ul injections would be a problem with these solvents.

My only remaining worry would be that if the sample has to be in THF to remain soluble, will it work ok with the running solvents/buffers?