Determination of TiO2 nanoparticles in cosmetic wastewaters by acid digestion coupled with ICP-MS

A rapid, simple and novel analytical method for the determination of traces amounts of TiO2in cosmetic wastewaters has been developed. The sensitivity of ICP-MS for direct determination of theelements of periodic table is more than most other techniques. Thus, ICP-MS is used as an effectiveanalytical tool to measure very low concentrations. Some of its other advantages include high lineardynamic range, high precision and accuracy in measurement and minimum interferences [1].The treatment method is based on acid digestion. The variables involved in the treatmentprocess were studied to provide the best extraction recovery. Around 5 mL of sample were treatedwith 500 μL of HNO3, 50 μL of H2O2 and 200 μL of HF using the following temperature program: upto 200 ºC (30 min), stabilization 1h at 200 ºC, up to 25 0 ºC (15 min), and stabilization at 250 ºCduring 1 h. Ultrapure water was added to all digested samples up to 10 mL in order to decrease theHNO3 and HF concentration in the solution before ICP-MS analysisThe method was successfully validated showing good linearity, limits of detection andquantification of 0.5 and 5.0 ng mL−1, respectively, and good repeatability (RSD < 7%). Finally, theproposed analytical method was applied to the determination of TiO2 in different cosmetic wastewatersamples with good relative recovery values (86–93%) thus showing that matrix effects werenegligible. The good analytical features of the proposed method besides of its simplicity andaffordability, make it useful to carry out the quality control of cosmetic wastewater.

Keywords:

TiO2 nanoparticles , Cosmetic wastewaters , Acid digestion , ICP-MS