Citric acid to change pH

labtechnicianlabtechnician Member
edited April 2014 in Formulating
Hi

Can anyone help me with Citric Acid? I would like to use citric acid to control pH of my cream and lotion. Can anyone tell me how much  citric acid (anhydrous - powder form) I need to add to change (0.5 to 0.7) pH? 

I also don't know how to use it? Should I add citric acid in water phase before heating or should I add in cool down phase after formulation? If I need to add in cool down phase after formulation, how can I add powder form of citric acid? Any comments or suggestions will be really appreciated?

Comments

  • Try making a 50% solution and adding that. Start by adding .05% increments.
  • Thanks @RawMaterialGirl..

    So this means I should add 50% solution at the end after complete formulation??
  • Chemist77Chemist77 Member, PCF student
    @lab pH adjustment is at the end of the process generally so yes it has to be added last.
  • DavidWDavidW Member, PCF student
    The better question is why would you want to adjust you pH up from 0.5 to only 0.7? 
    Is this some type of AHA cream or a chemical peel in cream form?  In my opinion you pH is way to low to be used by end user.  You are opening yourself up to legal ramifications should someone misuse the product and get hurt.  Do you have product liability insurance?
  • HI @DavidW..
     Sorry but you misunderstood my question? Actually My pH is around 5.5 and I want to reduce it to around 5.0 (0.5 to 0.7 reduction).

  • DavidWDavidW Member, PCF student
    ahhh, got it.  RawMaterialGirl is correct.  Make a solution (50%, 30%... up to you depending on the size you are trying to reduce.)  Depending on the size of your batch at the very end ofter all is done and cream is formed you can add drop by drop till you get the correct pH.  IF you are making a lot, then add by cc or grams of solution. 

    IF you are making large amount (20 gallons or more) you can try adding by grams of dry citric.
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