XRD is the best method to determine the phase concentration. however, before u use it, u must make sure that the sample must be in full crystalline. I suggest u should heat the sample at elevated temperature to remove polymer 1st, then test it by XRD.

Thank You Mr. Mohamad. Can you please tell me, how to find the copper content by xrd? If I heat the powder, there will be chances for making copper oxides also, then how to deal with that?

U r welcome. btw, the sample must be heated under decomposition temperature of CuO nanopowder, but higher than polymer. The polymer will evaporated and leave pure CuO. For phase composition, u can use Reitveld refinement method from PanAlytical HighScore Plus software to analyze the XRD profile

I prefer SEM-EDX method to find the composition, as it is an analytical technique used for the elemental analysis or chemical characterization of any sample

If you have a bulk sample (more than a few mg) the ICP-MS will do it. Our company (nanoComposix) regularly uses ICP-MS for measuring metal concentration in different nanomaterials. We dissolve them up, usually in nitric acid and then fire the samples into the ICP-MS.

Thank You Mr. Mohamad. Yes we are basically doing by the same way, you are talking about. But how to ensure, the presence of CuO only but not the formation of other oxidized phase of copper. It might be a combination of different copper oxides. How to resolve that problem?

Thank you Mr. Abdul Nishad P and Mr. Richard Baldwin. Whether ICP-AES and ICP MS are same and 100 mg sample is sufficient for analyzing or not? What are possible format of the output from these sample analyzers?

For further confirmation of impurities, XRF can be used.