Chromatography Forum

I hope the discussion made it clear that you should absolutely make a distinction between (1) cleaning the UPLC system (2) cleaning the column if you're considering rather harsh procedures.

(Most) LC columns will be unusable after treating them with strong inorganic acids. The good news is that columns are consumables, while the system is not. If you really have a stubborn organic contamination in the UPLC system, acid cleaning is your best bet. The procedures are not secret at all, try googling "Waters UPLC cleaning", or better replace "Waters" with whatever instrument type you're using. You will find both soft and harsh treatments, concentrated nitric/phosphoric acid cleaning is the last category. I followed a procedure employing 30v% phosphoric acid on an Acquity I-class UPLC and it worked to remove a stubborn organic contamination. I suggest before you start, contact the instrument manufacturer to make sure you will not be damaging the system.

Thanks RnDirk! for clarification and explanations, which helps understanding!

When you said "stubborn organic contamination" did you refer to organic or bio-contamination? organic can mean small organic molecules.

I have contacted Waters tech support. She and the people she had asked did not indicated that any of Waters solvents/acids cleaning steps/procedure would remove micro organism from an LC system. It may but the procedures do not intend to. It is not clear if it would be efficient for most micro organisms.

Thanks James.

It seems that it does need to change the seal after the peroxide and Nitric treatment. Correct?

Jim

It would depend on the seal material, but if there is that much contamination then I would do seal replacement as the last step to ensure everything is clean. Some seal material would be compatible with acid or peroxide, some materials not so much.

Thanks RnDirk! for clarification and explanations, which helps understanding!

When you said "stubborn organic contamination" did you refer to organic or bio-contamination? organic can mean small organic molecules.

I have contacted Waters tech support. She and the people she had asked did not indicated that any of Waters solvents/acids cleaning steps/procedure would remove micro organism from an LC system. It may but the procedures do not intend to. It is not clear if it would be efficient for most micro organisms.

I referred to organic contamination. I should have mentioned that I wasn't targeting micro-organisms. This discussion has me wondering now if there is something more appropriate than strong inorganic acids to remove micro-organisms from an LC system. I personally don't think so but this is not from experience, rather my view as a chemist.