It depends.... And I suspect you mean disperse rather than dissolve. Big difference.

Dear Sir Alan F Rawle,

Sir, I mean, that i have synthesized NPs but for characterizations and biological applications of NPs which solvent should be used to better dissolved and dispersed them before applications.

Javed Iqbal You cannot 'dissolve and disperse' your NP's. You have to do one or the other. I think there is a language barrier here. Are your materials in a colloidal state (already in suspension) or in powdered form (and therefore not 'nano')?

Dear Sir Alan F Rawle,

I want to properly dissolve them. My particles are in powder form.

Mostly methanol used as dispersion solvent for MNPs

Then we need to know which metal oxides. Most will dissolve in HCl (to give the chloride and metal ions) or in NaOH for some amphoteric oxides such as alumina. You will no longer have nanomaterials.

@Abdullah According to the poster the question appears to be 'dissolve' not 'disperse'.....

AlaN in poster they have mentioned disolve / disperse and nanoparticles are dispersed not dissolve for analytical applications

Abdullah .. Read the reply by Javed Iqbal : 'I want to properly dissolve them. My particles are in powder form'

I am simply answering that question even though I believe, like you, that what is actually wanted is dispersion. Maybe the OP wants to get rid of his particles by dissolving them? I can only rely on what the OP says; not speculate what he should be saying. So, on this basis, you are answering another question...

Respected Alan F RAWLE. I want to know from you that it is necessary for particles characterization that should be dissolve?

I am confused about this

For specifically dissolution, cold or hot, dilute or concentrated hydrochloric acid or sometime aqua regia (mixture of hydrochloric and nitric acid) may be useful for most metal oxides. You must have to try various possibilities.

Dear all,

I got it. Thanks to all of your for the cooperation. Be blessed.

Abdullah .. It May be needed to dissolve them for, say, ICP analysis or any other chemical anallysis.

Thank you Alan F RAWLE

methanol is a good dispenser where as Acetone is better. but it also depends on the size, shape and nature of the nano-particles, that what solvent will be better, even certain nano-particles are stable in Distilled water for days.

where as Alan F Rawle has good point for dissolution of nano-particles.

Thanks Dilawar bhaii but about DMSO?