I have synthesized citrate capped gold nanoparticle colloids using the Turkevich method and need to take TEM images of that. But I don't know what the procedure of sample preparation before taking TEM images is.
I do not know exactly what will be procedure for your particular case. But normally in case of nanoparticles, the dispersion of nanoparticles is made with a solvent like ethanol or toluene and then deposition on copper grid is made. You can find these copper grids online. I hope this may help you out