Dear Maziar:

The best and simplest method of cleaning metal nanoparticles from organic impurities is dissolved (washing) with solvents (hexane, dimethylformamide, water) and centrifugation.

Regards.

thanks a lot dear Yuri

Dear Maziar 

I also agree with Sir Yuri Mirgorod. Mostly we use water for removing impurities form bio-synthesized nanoparticles. Centrifugation is done at 10,000 -15,000 rpm for 10 minutes, while washing step is repeated 3 times for high efficiency. 

Thanks

To remove inorganic ions washed nanoparticles with deionized water follow by washing with ethanol in order to remove the losly bound organic molecules and then centrifuge at 5000 rpm for 20 minutes

thanks