Infrared spectra were performed (from 400 to 4000 cm⁻¹) in vitamins@P25TiO₂NPs samples and the vitamins alone as controls, employing a Nicolet AVATAR 360 Fourier transform infrared spectrophotometer.

The most significant uncertainty identified by the EU experts was the concern that TiO₂ particles may have genotoxic effects. Genotoxicity refers to the ability of a chemical to directly damage genetic material within a cell (DNA), which may lead to cancer in certain situations. Although the experts did not conclude that TiO₂ particles in E171 are genotoxic, they could not rule out the concern that they might be.