Home Cosmetic Science Talk Formulating Shampoo with 0.1% formalin turned yellow. Why?

  • Shampoo with 0.1% formalin turned yellow. Why?

    Posted by abdullah on December 17, 2021 at 1:48 pm

    I did make a sample of shampoo with 0.1% formalin. After few days it turned a bit yellowish. The same formula without formalin didn’t turn yellow. does it mean something bad happened and caused yellow color or it is normal for formalin in shampoo to turn yellow?

    Ingredients
    Water, SLES, SLS, CAPB, APG, cationic guar, Amodimethicone emulsion, NACL, citric acid, fragrance. 
    pH 4.5

    abdullah replied 2 years, 1 month ago 4 Members · 5 Replies
  • 5 Replies
  • oldperry

    Member
    December 17, 2021 at 2:26 pm

    I once made a big batch of white conditioner. When I poured it out, there was a big yellow streak near the bottom. It turned out, I had unknowingly dropped a small metal “chuck” (device to tighten the mixer) in the batch. I think it oxidized.  Perhaps you have excessive metal ions in your water in one batch that you didn’t have in your other batch. 

  • abdullah

    Member
    December 17, 2021 at 3:01 pm

    Perry said:

    I once made a big batch of white conditioner. When I poured it out, there was a big yellow streak near the bottom. It turned out, I had unknowingly dropped a small metal “chuck” (device to tighten the mixer) in the batch. I think it oxidized.  Perhaps you have excessive metal ions in your water in one batch that you didn’t have in your other batch. 

    I made both samples in glass jar, mixing with same type metal spoon and stored them in PET plastic bottle. 
    I forgot to mention above, they both had 0.2% tetrasodium EDTA that i add to everything.

    I will make another batch and see if that was the case.

    About this metal oxidation, is it only iron that oxidizes is such products or any metal?

  • Quimico

    Member
    January 5, 2022 at 4:20 pm

    Use EDTA 0.1% AS PRESERVATIVE & CHELATING AGENT 

  • bill_toge

    Member
    January 5, 2022 at 8:23 pm
    it does go yellow, but not usually that quickly - what’s the ambient temperature where your samples are?
    also, how old is your formalin solution? depending on the age, it may contain oligomers and other impurities
  • abdullah

    Member
    January 6, 2022 at 3:23 am

    Bill_Toge said:

    it does go yellow, but not usually that quickly - what’s the ambient temperature where your samples are?
    they were in bathroom ≤25°c. They were my first sample with formalin and we were checking if they cause irritation or not from Shampoo.
    also, how old is your formalin solution? 
    this i don’t know and may not be able to know. depending on the age, it may contain oligomers and other impurities
    is this impurity produced by age in all formalin or what?
    Does it have any side effects?

    Does formalin that goes yellow has less preservative efficiency or any side effects?

    @@Bill_Toge thanks

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