Chromatography Forum

I've been working with organic buffers, primarily 40mM ammonium formate/formic acid solutions. As is the case when I typically use buffers, at the end of the day I'll always spend the 30min to wash out my system with pure H2O, and the next morning I'll spend another 30min-1hr re-equilibrating my system to the previous conditions - but in this case I'm not exactly sure why I do it. Even at 95:5 MeOH:buffer, I know there is no chance for the buffer to precipitate as ammonium formate is soluble in methanol. Microbial growth might be an issue, but there is no circumstance when there isn't at least 30% MeOH running through the system.

For situations like this, is there really any necessity for me to go through this washing/re-equilibrating process everyday? What's going to happen if I leave formate buffer in my system/column for a day, a week, a month? Can anyone shed some insight on my situation? Thanks!

For one day I would set up flow rate at 0,1ml/min, that will save you 1 hour washing time. For 1 week or one month I would rinse the column and according to the manufacturers manual store in the recommended storing solvent. What ever could happen on the column with your buffer cannot happen then.

We do what Gerhard has suggested, as it saves both flush time and reequilibration time for next-day use.

Meaning you just allow the system to run at a 0.1ml/min flowrate overnight, obviously with the detector lamp off, to keep things flowing? Thanks.

I guess I should just install the solvent valve module, that way switching between solvents won't be such a pain.

Meaning you just allow the system to run at a 0.1ml/min flowrate overnight, obviously with the detector lamp off, to keep things flowing? Thanks.

Yes.

Do you see an improvement now?