Optimization of mineralization methods of TiO2 nanoparticles: Determination of titanium levels in rat organ tissues

In order to draw appropriate conclusions about the possible adverse biological effects of titanium dioxide nanoparticles (TiO2-NPs), the so-called “dose-effect” relationship must be explored. This requires proper quantification of titanium in complex matrices such as animal organs for future toxicological studies. This study presents the method development for mineralizing TiO2-NPs for analysis of biological tissues.
We compare the recovery and quantification limits of the four most commonly used mineralization methods for metal oxides. Microwave-assisted dissolution in a HNO3/HF mixture followed by H2O2 treatment produced the best results for a TiO2-NP suspension, with 96 ± 8 % recovery and a limit of quantification as low as 0.885 µg/L. This Method was then used for the determination of titanium levels in tissue samples taken from rats. However, our tests revealed that even this method is not sensitive enough for quantifying titanium levels in single olfactory bulbs or in hippocampus in control rats.