thanks so much! I think the purity has no problem. it's from Roquette. what puzzles me is that why does the phenomenon should happen while the concentration is much lower than its solubility. And the method you provide helps me a lot. :smile:
when i add mannitol into water, the solution has opalescence. Does the solution forms colloid? Then how should I do to delete it? Thank you very much...:smile: