I have synthesized CuO nanoparticles using copper sulfate (CuSO4.5H2O) and Urea as preventing aggregation agent. My CuO was calcinated in 500 degrees for 2 hours. From FTIR spectrum, I got small sharp peak in region 3600-3500 cm-1 indicated N-H vibration from Urea. I want to totally remove organic compounds from my CuO NPs.