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Iso-electric point of allantoin
Can someone tell me the iso-electric point of allantoin? Or where to find it or how to calculate it?
(I want to know for sure from which pH I can use it together with anionic substances.)Thanks! :+1:
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6 Replies
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According to Merck, the following is true of a 5% solution in water:
pH = 4.5 - 6 (5% in water, 20 deg C)
https://pubchem.ncbi.nlm.nih.gov/compound/allantoin#section=Vapor-Pressure
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@Perry
So allantoin has a neutral charge between pH 4.5 and 6, below 4.5 cationic and above 6 anionic?
Edit: Would it be very different if the concentration decreases to 0.5%, or lower?Thanks so much, Perry! :+1: :smiley:
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@Doreen at 25 degrees C It is probably the same as the solubility is about 0.6% in water.
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@Sibech
Ok, thanks a lot!! -
@Doreen - well not exactly. I believe it is a weak acid so it wouldn’t be correct to claim it’s ever cationic. It either has a negative charged ion at lower pHs or it is neutral. See the structure of allantoic acid.
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@Perry
You’re right! I thought it had a negative charge at higher pH’s.
( Ingredients To Die For is also mistaken I see: ‘Allantoin is an amphoteric compound that is anionic under basic conditions.’)
Thanks for clearing that up! Now I know I never have to worry combining it with anionics.
Thanks!!
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