Home Cosmetic Science Talk Formulating Advanced Questions Zinc oxide & rosemary

  • Zinc oxide & rosemary

    Posted by Anonymous on April 26, 2017 at 6:30 am

    Hi All,
    I need help please!

    If I use the zinc oxide and rosemary CO2 together, the product’s color change to purple ( at 5,5 ph is dark purple). This phenomenon occurs is not only in the emulsified product but also in water- free ( balsam) Can you help why make it?
    thank you!

    drbobverdient-biz replied 6 years, 11 months ago 3 Members · 3 Replies
  • 3 Replies
  • johnb

    Member
    April 26, 2017 at 7:09 am

    As an initial thought, how pure is the zinc oxide?
    Rosemary extracts are phenolic and phenols characteristically react with iron to produce an intense red or purple colour. As iron is a common contaminant of ZnO it could be that reaction.

  • bobzchemist

    Member
    April 26, 2017 at 1:50 pm

    How pH stable is the color?

  • drbobverdient-biz

    Member
    April 27, 2017 at 2:29 pm

    Redox-at low PH zinc ions are likely reacting with Fe ions to discolor.I would first raise PH to 7 and observe color.

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