How to measure the purity of powder

There are several techniques that can be used to test the purity of a powder. One common method is X-ray diffraction analysis (XRD), which can be used to identify and quantify the different crystalline phases in a powder. Another technique is Raman spectroscopy, which can detect the unique vibrational modes of different molecules and is sensitive to impurities. Other methods include thermogravimetric analysis (TGA), which can be used to measure the weight loss of a sample as it is heated and can indicate the presence of contaminants that have different thermal stabilities than the desired compound, and elemental analysis, which can be used to measure the concentrations of different elements in a sample and identify impurities.