Home Cosmetic Science Talk Formulating Technical Specifications of Sodium Chloride

  • Technical Specifications of Sodium Chloride

    Posted by MurtazaHakim on September 11, 2022 at 8:52 am

    Dear readers,

    What type of sodium chloride should be used for thickening the liquid detergents and soaps ? I have a sample of common salt which when dissolved in tap water of pH 8.3 indicates a pH of 7.3 and the QC chemist insists that if this common salt is dissolved in water of pH 7, it would decrease the pH of that solution to 6. Is it necessary to use USP grade Sodium Chloride for production of products like dishwashing liquid ? Usually common salt is neutral in pH. Could there be something wrong in the tap water ?

    PhilGeis replied 1 year, 6 months ago 3 Members · 6 Replies
  • 6 Replies
  • PhilGeis

    Member
    September 11, 2022 at 8:56 pm

    USP grade is not needed for this application.  But you should know composition.
    pH of dishwashing liquid is typically alkaline (Dawn is 9) as adjusted by e.g. NaOH.  
    “Tap” water pH is usually slightly alkaline but can be highly variable.  EPA secondary drinking water standards specifies 6.5-8  https://www.epa.gov/sdwa/drinking-water-regulations-and-contaminants

  • abdullah

    Member
    September 12, 2022 at 1:02 am

    PhilGeis said:

    USP grade is not needed for this application.  But you should know composition.
    pH of dishwashing liquid is typically alkaline (Dawn is 9) as adjusted by e.g. NaOH.  
    “Tap” water pH is usually slightly alkaline but can be highly variable.  EPA secondary drinking water standards specifies 6.5-8  https://www.epa.gov/sdwa/drinking-water-regulations-and-contaminants

    Should hand dishwashing liquid also have pH 9 or it should be lower to be gentle for skin?

  • MurtazaHakim

    Member
    September 12, 2022 at 5:45 am

    The test report of the salt sample received indicates NaCl content as 99.6%. The following data is indicated in the test report.  

    1. pH - 7.0
    2. Moisture - 0.15 %
    3. Insolubles - 0.05 %
    4. Calcium - 0.06 %
    5. Magnesium - 0.02 %
    6. Potassium - 0.01 %
    7. Sulphate - 0.09 %
    8. NaCl - 99.60 %
    9. Iodine - 15-40 MG/KG

    This is actually a food grade iodized salt. Is it fine to use iodized salt for cleaning products ?

  • PhilGeis

    Member
    September 12, 2022 at 9:46 am

    Don’t think all ingredients must be food grade but not up on food reg’s.    Iodized salt is obviously used as a direct food ingredient but prob more expensive than without.  suppose you could use GRAS spec if concerned.
    Off target from your question - what is your preservative?

  • MurtazaHakim

    Member
    September 12, 2022 at 12:18 pm

    The preservative is a blend of MCIT & MIT.

  • PhilGeis

    Member
    September 12, 2022 at 1:48 pm

    Right - that should work well - esp at near neutral.
    @Abdullah - I don’t know enough to address gentle and pH.

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