Hi,

I think there is a small misunderstanding with the nanoparticle concept here (Please apologize if I am mistaken). They are solids, which in principle can be dispersed as a colloid in a solvent, be it organic or inorganic. They will indeed react with strong acids or bases, but you end up losing the parent SnO2 nature. 

You can refer this paper for some idea. 

http://pubs.acs.org/doi/abs/10.1021/jp050334g?journalCode=jpcbfk

All the best.

try ethers or alcohol may be used as solvent

Dear Sirajul

try dilute sulfuric acid and small quantity of Cresolsulphonic acid to dissolve SnO2. Because Cresolsulphonic acid would be minimize the further oxidation of Sn(II).

Hi Aswin,

What do you mean by "parent SnO2 nature"? Does SnO2 loose its photocatalytic oxidizing property if it is solved with an acid or base?