Sulfur Kβ X-ray emission spectroscopy: comparison with sulfur K-edge X-ray absorption spectroscopy for speciation of organosulfur compounds
Muhammad Qureshi, S. Nowak, Linda Vogt, Julien J. H. Cotelesage, Natalia V. Dolgova, Samin Sharifi‐Asl, Thomas Kröll, Dennis Nordlund, Roberto Alonso‐Mori, Tsu‐Chien Weng, Ingrid J. Pickering, Graham N. George, Dimosthenis Sokaras
Abstract
Until recently, sulfur was known as a "spectroscopically silent" element because of a paucity of convenient spectroscopic probes suitable for in situ chemical speciation. In recent years the technique of sulfur K-edge X-ray absorption spectroscopy (XAS) has been used extensively in sulfur speciation in a variety of different fields. With an initial focus on reduced forms of organic sulfur, we have explored a complementary X-ray based spectroscopy - sulfur Kβ X-ray emission spectroscopy (XES) - as a potential analytical tool for sulfur speciation in complex samples. We compare and contrast the sensitivity of sulfur Kβ XES with that of sulfur K-edge XAS, and find differing sensitivities for the two techniques. In some cases an approach involving both sulfur K-edge XAS and sulfur Kβ XES may be a powerful combination for deducing sulfur speciation in samples containing complex mixtures.