Chromatography Forum

Hi
I am required to use 80:20 [THF:H20] mix for my HPLC column. I am worried about the stability of the buffer as I ve read that THF being an organic ether has a tendency to form explosive peroxides on interaction with atmospheric oxygen. Can somebody please let me know how long I can store my buffer safely/normally on my bench without worrying about this problem? I am using the HPLC grade solvent without the BHT additive. The only other solution I got by calling tech support from the company I got the reagent from was to purge the bottle I am storing my buffer in with nitrogen or argon gas and to not use it/store it beyond 2-3 days.

Thanks

With 20% water, I wouldn't worry too much about explosives. What is of more concern is the UV background and contaminant peaks. Best practice is to store the THF in the fridge under nitrogen and make up mobile phases fresh each day.

Thanks Tom. But I ve read that THF can form crystals with water at low temperatures. So I am planning on storing it on my bench at room temperature, tightly sealed, shielded from light. By any chance could you direct me to an article that discusses rate of peroxide formation in THF?

Past reading I've done (don't ask for the source) indicates that once some water has been added, THF is much less likely to form peroxides.

There are peroxide test strips available, you give them a quick dip in a sample of your solution and see if they turn pink. If they don't turn, you're OK with respect to peroxides. Testing any THF stocks and mixtures on a monthly basis should pacify the safety folks. Your UV detector will probably be even more sensitive to changes in your mobile phase.

I agree with Tom - nitrogen blankets and a refrigerator will help keep it stable. A gentle Helium sparge (just a trickle) while your use it as mobile phase would also be a good idea.

I keep telling people they should use the search function. I should learn to follow my own advice!

More re THF stability:
viewtopic.php?f=1&t=4830

That was very helpful. Thank you.