Outgassing of volatile sulphur compounds from gypsum drywall from some sources has resulted in odours, corrosion of wiring and metals and health problems for homeowners. Infrared spectroscopy has been the primary analytical tool to identify 'problematic' drywall. In this paper, we demonstrate that elemental fingerprinting using inductively coupled plasma mass spectrometry and multivariate statistics is an effective alternative. The approach also showed potential in determining the geographic source of gypsum. Nineteen elements (Al, Ba, Ca, Cd, Co, Cr, Cs, Cu, Fe, Mg, Mn, Ni, Pb, Rb, Sr, Tl, U, V and Zn) were measured in 20 samples of drywall, half of which were classified as positive for contamination by Fourier Transform Infrared Spectroscopy. Gypsum from three different mines and a flue gas desulphurisation plant were also analysed. Principal component analysis and multivariate analysis of variance of the elemental data showed significant differences between the problematic and non-problematic drywall and between sources of gypsum. Strontium averaged 1800 ± 500 µg/g in problematic drywall compared to 400 ± 100 µg/g in non-problematic drywall (p < 0.0001).

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Iodine was chemically separated from NTS near-field groundwater samples and analyzed for its 129 I/ 129 I ratio on a Multi-Collector Inductively Coupled Plasma Mass Spectrometer (MC-ICPMS). The measured ratios were then compared to 129 I/ 129 I ratios for identical samples run on the Accelerator Mass Spectrometer (AMS). The MC-ICPMS results in some cases differed from the AMS values by more than an order of magnitude. The disparity in the results is due to isobaric interferences at mass 129 from polyatomic species and 129 Xe in the MC-ICPMS plasma gas. It is anticipated that the interferences can be largely eliminated by (1) improving the molybdenum separation chemistry using a 92 Mo-spike precipitation method, and (2) introducing O 2 to the plasma gas to reduce the 129 Xe interference. The MC-ICPMS detection limit for 129 I/ 127 I (measured on reference standards) is on the order of 1E-6 or slightly lower. Most near-field groundwater samples have 129 I/ 127 I ratios >1E-6, and should be measurable on the MC-ICPMS once the isobaric interference issues are resolved.