• Formulating

  Will mix citric acid with CAPB neutralize it’s impurities like DMAPA and LAPDMA?

  Posted by Abdullah on January 27, 2025 at 5:23 am

  I purchase CAPB locally and it has very dark color so it may have a lot of impurities.

  If i mix it with some citric acid before mixing it with other surfactants, will it neutralize impurities like DMAPA and LAPDMA etc?

  ketchito replied 18 hours, 12 minutes ago 2 Members · 6 Replies
• 6 Replies

• 

  ketchito

  Member

  January 27, 2025 at 6:54 am

  Yes, and that’s the same recommendation (I believe from Colipa) to neutralize secundary amines and prevent nitrosamine formation. Now, I’d be more worried about the very dark color for other reasons as well. Did you run a microbial test?

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    Abdullah

    Member

    January 27, 2025 at 7:16 am

    No i dont run the test.

    They are either preserved with formalin or CMI MI.

    What else coud be the reason?

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    Abdullah

    Member

    January 27, 2025 at 8:06 am

    Also if i use cocamide methyl MEA as co surfactant for SLS: SLES instead of CAPB it feels milder and better scalp feel after hair is dried. I dont know if it is because of impurities in my CAPB or MEA reduces irritation of SLS: SLES more than CAPB .

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  ketchito

  Member

  January 28, 2025 at 12:26 pm

  I still believe CAPB rules! Let me elaborate. The synergy you see when mixing amphoterics like CAPB with anionics such as SLES is mostly due to the quaternary amine present in CAPB (besides the hydrogen bonds from the amide group, of course), which is missing in CAM MEA. While CAM MEA could potentially have a positive charge in some conditions, that species is not very stable and it’ll prefer to have a neutral configuration. Because of that, CAPB is my dog (sorry about the slang!).

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    Abdullah

    Member

    January 28, 2025 at 7:59 pm

    Thanks. I currently add 0.3% citric acid to my shampoos. It reduces pH to ~4.5 when CAPB is present in water.<div>

    Is this much citric acid enough to mix with water and CAPB and mix for some time, then add other ingredients and increase pH back to 6 or i should add more citric acid?

    Also is heading the product necessary to neutralize impurities or cold mixing is enough?

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    • 

      ketchito

      Member

      January 29, 2025 at 5:15 am

      If it’s a cosmetic product, I’d stay around a pH of 5. Heating would improve water quality (at high temperature), but some impurities are heat resistant. Adding an acid might neutralize the basic ones, but not all of the impurities are basic. Now, chances are you won’t have impurities in your product that could compromise health at the usual levels, but adding a chelant to prevent catalytic activity of some metal ions could be a good practice (which I’m sure you do).

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