- #1
tzhisun
- 2
- 0
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...
Why mannitol solution 0.05% has opalescence？how to delete it?
- Thread starter tzhisun
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Discussion Overview
The discussion centers around the opalescence observed in a 0.05% mannitol solution when mixed with water. Participants explore potential causes for this phenomenon, including the possibility of colloidal formation and impurities, as well as methods to eliminate the opalescence.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
Main Points Raised
- One participant questions whether the opalescence indicates the formation of a colloid and seeks methods for its removal.
- Another suggests checking the solubility of mannitol in distilled water and proposes that impurities may be responsible for the opalescence, recommending filtration or gentle heating as potential solutions.
- A later reply reiterates the solubility check and emphasizes the need for purity, suggesting that the opalescence could stem from impurities or a stabilizing agent keeping mannitol in a colloidal state.
- Participants mention various purification methods, including crystallization and chromatography, as possible approaches to address the opalescence.
Areas of Agreement / Disagreement
Participants generally agree that impurities may be causing the opalescence, but there is no consensus on the exact cause or the most effective method for removal. The discussion remains unresolved regarding the underlying reasons for the phenomenon.
Contextual Notes
Participants express uncertainty about the purity of the mannitol and the specific conditions under which the opalescence occurs, indicating a need for further investigation into the solubility and potential impurities.
Who May Find This Useful
This discussion may be useful for individuals involved in chemistry or pharmaceutical formulations, particularly those working with mannitol or similar compounds.
- #2
phildukephd
- 3
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Look in a reference source for the solubility of mannitol in distilled water. If it is greater than 0.05% an impurity may be causing the opalescence. If so try filtration to remove it, or gentle heating to precipitate it. Purification by crystallization or chromatography may be in order. What does the supplier say about the purity?
- #3
tzhisun
- 2
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phildukephd said:
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.
- #4
phildukephd
- 3
- 0
Opalescence usually is due to particles large enough to reflect light, possibly a colloidal solution. If so remove the colloid by filtration, centrifugation, precipitation, etc., make sure your distilled water is pure. Since mannitol is very water soluble, the opalescence is likely due to an impurity, or conceivably a stabilizing agent keeping some mannitol in the colloidal state. The supplier should give info on purity. If necessary purify by recrystallization, chromatography, etc. Good luck.
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