Particle Size Testing and Raw Material Testing in General for cosmetics (chemistry, physical, etc).

I am testing all incoming raw materials before releasing it to be used in finished product as part of a new supplier qualification program I am trying to establish.  This has not been done prior to my Direction as head of QC, so I have no trending history to base my decisions on for any anomoly I might encounter in testing.

Some of our raw materials are failing specification for pH and Particle Size (as an example), whereas within formulation would typically pass; however, I want to be wary of "order of addition" issues and know that sometimes the raw material result can count as much or more than the final pH.

I do not know how to proceed for these raw materials that are not passing spec and whether or not I should "release" them?  Based on histroy, our finished product has never been rejected or had failures to do pH or Particle size... and obviously I cannot change the specification for particle size as that is set by federal guidelines (recommendations).  


  • chemicalmattchemicalmatt Member, Professional Chemist
    In which nation-state or parallel universe are raw material specs dictated by 'federal guidelines'? Unless you are speaking of an aerosol?
  • ozgirlozgirl Member, PCF student
    Normally raw materials are just tested against suppliers specifications. If the supplier says a 1% solution of the material is 6-7 you should be able to get the same result.

    Do your QC methods differ from the ones the supplier uses? This could be the difference for the variances you are seeing.

    Since you do not seem to be having any troubles with production and final formulation specifications, I would just record QC results for a period to get an idea of variances in your raw materials.
  • chemicalmattchemicalmatt Member, Professional Chemist
    Ditto ozgirl's remark. Nobody here in the USA says you cannot create your own specs for a given raw material, broadening the range as you see fit (and within your personal testing capability.) Makes life easier, no?
  • Yes my internal specs are different than supplier, because supplier specifications often do not suffice in my opinion for the specs we are trying to meet for finished product.  But I definitely like the school of thought of just testing them against their own standards at least; however, I will be more selective on supplier in the future based on the testing/specifications they have for theirown raw materials.
  • If your methods are matching the company's and your results are not then take that up with them. When I worked in QC at a chemical company we had several accounts that set their own specs that were narrower than our own.
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