Foreign Matter identification

Hi There, we have an issue in our production facility in that when we make certain products with no viscosity (such as some toners or room sprays) the products develop a sediment of small particles over time that float around at the base of the product.  The bulk is filtered with a 10 micron filter at production so it is not contamination from a raw material, but rather a particle that is developing over time.  It appears as small grey or black particles.  They also do not occur consistently and some batches will develop them and some will not.  They occur at room temperature after anywhere from 3-6 months.  Does anyone have any idea what they could be - does a particular ingredient in this formulation stand out as the cause?  We suspected metal ions and increased the chelating agent in the product but it didn't help.  Alternatively does anyone know of a laboratory we can send a sample to that could possibly identify this foreign particle?  This is the formulation of a toner that is sometime affected.

RAW MATERIAL %
Aqua 84.01
Hamamelis Virginiana Water 5
Rosa Centifolia Flower Water 5
Propylene Glycol, Methylparaben, Propylparaben, Diazolidinyl Urea 1
Propylene Glycol 1
Glycereth-26 1
Disodium EDTA 0.8
Polysorbate-80 0.7
PEG-40 Hydrogenated Castor Oil 0.5
Parfum 0.4
Benzophenone-4 0.2
Allantoin 0.1
Camellia Sinensis Leaf Extract, Bambusa Vulgaris Shoot Extract, Propylene Glycol 0.1
Cetrimonium Chloride, Isopropyl Alcohol 0.05
Citric Acid 0.05
Sodium Hydroxide 0.05
CI 42090 0.015
CI 19140 0.009
CI 17200 0.005
Hydrolyzed Silk 0.01
Bisabolol 0.005
  100.00

Comments

  • What are the CIs?

    Please try without the plant extracts, or try adding some antioxidant like BHT to see if it works.
    You may need to wait several months to get the answer, so try to make as many different test batches as you can.
  • Hi Gunther.  The CIs are colour pigments.
  • CI 42090 - Brilliant Blue FCF
    CI 19140 - Tartrazine yellow
    CI 17200 - Acid Red 33

    All of which are water-soluble dyes, not pigments.
    Does the colour of the product change during/after precipitation

    Seeing as you have to wait for several months you can add antioxidants as @Gunther suggested and do a knock-out (removing one ingredient) with all possible ingredients (except water of course)?
    Dabbling Formulator, cosmetic safety assessor, and experienced in claim substantiation & EU regulatory affairs.
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