ANALYSIS OF MIXTURES OF COMPOUNDS OF COPPER USING K-EDGE X-RAY ABSORPTION-SPECTROSCOPY

A determination is described of copper metal, oxide, and hydroxide in samples containing both nickel and copper. The analysis was based on K-edge x-ray absorption spectra of the copper. This allowed us to consider the chemical states of copper and ignore the nickel also present. The method involved fitting linear combinations of copper standard spectra to the spectrum from copper in the sample. The fit composition that minimized the variance gave the sample composition. The work demonstrated that K-edge x-ray absorption spectra are sufficiently characteristic to allow their use for quantification of components in mixtures. This method of analysis is complemented by diffraction and less general techniques. It is a strength of x-ray absorption edge analysis that it is element-specific and applicable to most elements maintained under any conditions of temperatures, pressure, and atmosphere.