[G.B]

I have to separate a mixture of organic compounds by column chromatography. This separation was successful in the past. But when I use a new alumina (contained in a sealed container), with the same identification code of the old one, my products don't move from column head. Why? Should I have to activate alumina? Do you know how?

Thank you!

[Donphil07]

may be your alumina has a little water, make dry it in 100oC.