A Comparative Study of the Methods of Speciation Using X-ray Absorption Fine Structure

Abstract

Determination of the chemical forms along with the relative quantity of the dierent species in a given sample, termed as speciation, can be done by analyzing X-ray absorption ne structure spectra. The dierent methods that can be used for speciation are: principal component analysis, target transformation, methods based on derivative spectra, method based on the relative position of the absorption edge, residual phase analysis, normalized dierence absorption edge spectra analysis and linear combination tting. An attempt has been made to make a comparative study of these dierent methods of speciation by recording the X-ray absorption ne structure at the copper K-edge in a mixture having cuprous oxide and cupric oxide in a specic ratio. The X-ray absorption ne structure spectra of the two oxides have also been recorded separately and the dierent characteristic X-ray absorption near edge structure features have been identied and their origins have been discussed. Speciation of the mixture has been done using these dierent methods and the results obtained have been compared and discussed.