[blackpavvn]

I am trying to develop a method to test Titanium dioxide in creams and i keep constantly getting low numbers. I digest the sample with hydrofluoric acid/Nitric acid in a microwave digester, I get a clear colorless solution, with no percipitate. I adjust it to volume with water and then i run it in the AA, and every single time i get about 60-80% of the total concentration of Titanium dioxide... am i missing something?

[Stepan]

Digest the micro-sample (1-3 mg) with 1 mL HNO3 and 2 mL H2SO4 in a conical beaker and heat until about 1 mL remains. Quantitatively transfer the solution to a 25-mL volumetric flask, add 5 mL of 5,000 µg/mL potassium ion, then dilute to volume with DI H2O.

Use standards with the same concentration of potassium and sulfuric acid in DI water.

I did this test a month ago, recovery from TiO2 crystalline was more than 95%.

[blackpavvn]

Thank you, will try that