Dear Noh,

I am confused about your mentioned word dissolved. Are you sure about the fact of dissolving or dispersing ZnO or TiO2 in organic solvent?

If you want to dissolve them in organic solvent, i am afraid they might not get dissolved. They are not usually dissolved in common polar or non-polar solvents.

If you want to dissolve them you can take hot concentrated hydrochloric acid, sulfuric acid,and nitric acid. However they might not got dissolved in oxide form rather you had to take sulfides or chlorides of them.

And if you want to disperse them you can try with DMSO, chlorobenzene , toluene or isopropanol.

Convert them into Methyl Acetate friendly salt and dissolve it.