X-Ray Fluorescence and FT-IR Identification of Strontium and Carbonate in Domestic and Imported Gypsum Drywall

摘要

Drywall samples originating in the U.S. and elsewhere were obtained from several sources and investigated using X-ray fluorescence (XRF) and Fourier-transform infrared (FT-IR) spectroscopy. XRF shows elevated levels of strontium in the imported samples compared with those from the U.S. The FT-IR analysis shows the samples match the known resonances of gypsum yet also have contaminant peaks in the spectra of four of the nine samples. Smaller peaks at the same locations were seen in two samples from the U.S. and the peak was extremely weak or missing in three of the samples. A comparison to reference spectra suggests that the observed peak at 1442 cm~(-1) corresponds to a carbonate mineral. Thermogravimetric IR analysis shows further evidence of the presence of carbonates and a link to sulfur-based compounds.