Chelator for acids

I was wondering if disodium EDTA would be an effective chelating agent in my lactic or glycolic toner with a pH of 3.6-3.8? If not, what could be used?
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  • EVchemEVchem Member
    It should work fine, EDTA has better solubility with increasing pH. Just test and see if it dissolves. 
     Phytic acid is also a chelator and it will keep your pH very low. I prefer it because it's more biodegradable than  EDTA
  • ifamujifamuj Member
    EVchem said:
    It should work fine, EDTA has better solubility with increasing pH. Just test and see if it dissolves. 
     Phytic acid is also a chelator and it will keep your pH very low. I prefer it because it's more biodegradable than  EDTA
    Thanks a tonne! Phytic acid is harder to obtain, though.
  • PharmaPharma Member, Pharmacist
    Phytic acid works at bit better at lower pH than EDTA ;) .
    EDTA works for Fe(III) but the instant you add a good antioxidant, you generate Fe(II) whose EDTA complexes dramatically lose stability below pH 4 and attain useless stability at pH 3.
    All/most other heavy metals one wants to chelate show similarly poor chelation at such a low pH.
    If memory serves me right, gluconic acid is also better at low pH.
    BTW do you really need a chelate?
  • Pharma said:
    Phytic acid works at bit better at lower pH than EDTA ;) .
    EDTA works for Fe(III) but the instant you add a good antioxidant, you generate Fe(II) whose EDTA complexes dramatically lose stability below pH 4 and attain useless stability at pH 3.
    All/most other heavy metals one wants to chelate show similarly poor chelation at such a low pH.
    If memory serves me right, gluconic acid is also better at low pH.
    BTW do you really need a chelate?
    How do you determine whether you need a chelator or not? Doesn't simply adding water mandate that you add one?
  • PharmaPharma Member, Pharmacist
    Depends what you have in your product. A low pH such as yours with proper preservation and not much bug food and no unsaturated fatty acids are usually not an issue.
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