Why mannitol solution 0.05% has opalescence？how to delete it?

[tzhisun]

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...

 

[phildukephd]

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?

 

[tzhisun]

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?

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.

 

[phildukephd]

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.

 

[LudusRex]

Mannitol is a sugar alcohol that is commonly used in scientific experiments and medical treatments. When dissolved in water, mannitol can exhibit opalescence, which is the cloudy or milky appearance of a solution. This opalescence is due to the formation of small particles or droplets in the solution, which can scatter light and give it a cloudy appearance.

The opalescence in a 0.05% mannitol solution is likely caused by the formation of a colloidal suspension. A colloid is a mixture in which one substance is dispersed throughout another substance in small particles, creating a cloudy or milky appearance. In this case, the mannitol particles are dispersed in the water, creating the opalescence.

To remove the opalescence from the solution, there are a few options you can try. One method is to filter the solution through a filter paper to remove the particles. Another option is to centrifuge the solution, which will separate the particles from the liquid and create a clear solution. You can also try increasing the temperature of the solution, as this can sometimes help the particles to dissolve.

It is important to note that the opalescence in a 0.05% mannitol solution does not affect the effectiveness of the solution in experiments or medical treatments. However, if you require a clear solution for your experiment, it is important to remove the opalescence before proceeding. I hope this information helps and please let me know if you have any further questions.