Home Cosmetic Science Talk Formulating Accurate ph for clay mask

  • Accurate ph for clay mask

    Posted by greensara on September 8, 2017 at 7:27 pm

    I’ve had an ongoing issue measuring ph with a clay mask formulation. I understand that solids are going to pose a challenge, but did assume my readings would be consistent and somewhat accurate (not fluctuate so much during readings). The product contains Honey, Water (10%), Fuller’s Earth, Glycolic, Citric, Tartaric and Lactic acids, Glyceryl Caprylate, Glycerin, Sodium Levulinate, Sodium Anisate. The ph meter has been calibrated, and even when diluted my readings are fickle. We are shooting for a ph of 3.8-4.

    Any suggestions or insights would be most appreciated.

    greensara replied 6 years, 7 months ago 3 Members · 4 Replies
  • 4 Replies

    September 8, 2017 at 9:13 pm

    try another meter if you can and/or cover the beaker around the electrodes when taking measurement.

  • Bobzchemist

    September 9, 2017 at 9:57 pm

    Try using a flat-surface probe, or one designed for high-viscosity products. General purpose electrodes don’t work reliably with high-viscosity/high-solids formulations.


    September 10, 2017 at 2:45 pm

    If dilution is still causing fluctuations something hygroscopic in formula (acids) are absorbing water from the air so try dilution and covering first.I have seen this before.

  • greensara

    September 28, 2017 at 7:03 pm

    Update: We used a 10% dilution and a new electrode. Slope was around 90, and numbers were spot-on so it appears that the electrode was the culprit. Ph turned out to be very close to our intended mark. Thank you so much for the replies - great insight and suggestions I’ll keep in mind if this should come up again.

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