Fig. 2

Number-based PSDs of TiO2 particles determined by spICP-MS. (A) The PSDs of TiO2 particles of E 171-1 and E 171-2 dispersed in ultrapure water. (B) The PSDs of TiO2 particles of feed samples containing E 171-1 or E 171-2 after successive digestion with artificial saliva juice, artificial gastric juice, and artificial intestinal juice