Making TiO2 dissolve in acid organic

[Desy]

Hi, everyone..
I do want to know, what are parameters that I have to know to dissolve TiO2,,?? I have tried many solvents like H2SO4, HCl, HNO3, citric acid, ascorbic acid, equi-molar citric/ascorbic acid,, but all was fail.
could you tell me,,??
Thank you.. :)

 

[SteamKing]

See this article, p. 2:

ftp://ftp.fao.org/ag/agn/jecfa/cta_tio2.pdf

You can forget citric acid or ascorbic acid. TiO2 only slowly dissolves in hydrofluoric acid or hot, concentrated sulfuric acid, both of which are extremely dangerous to handle.

Why the interest?