Do DCVC columns need to be changed?



I’ve been using an ethanol alumina column for dozens of runs in a row, and haven’t noticed any noticeable difference in efficacy. I use an etoh/water gradient

Is there anything that happens physically/chemically to the alumina to necessitate it’s change? Or as long as I clean it can it be used indefinitely?


I realize most people just discard the column in favor of keeping solvent, but the etoh to clean it is pretty cheap, and keeping downtime negligible is paramount.