title: Cross calibration between XRF and ICP-MS for high spatial resolution analysis of ombrotrophic peat cores for palaeoclimatic studies.
abstract: Ombrotrophic peatlands are remarkable repositories of high-quality climatic signals because their only source of nutrients is precipitation. Although several analytical techniques are available for analysing inorganic components in peat samples, they generally provide only low-resolution data sets. Here we present a new analytical approach for producing high-resolution data on main and trace elements from ombrotrophic peat cores. Analyses were carried out on a 7-m-long peat core collected from Danta di Cadore, North-Eastern Italy (46° 34' 16″ N, 12° 29' 58″ E). Ca, Ti, Cr, Fe, Cu, Zn, Ga, Sr, Y, Cd, Ba and Pb were detected at a resolution of 2.5 mm with a non-destructive X-ray fluorescence core scanner (XRF-CS). Calibration and quantification of the XRF-CS intensities was obtained using collision reaction cell inductively coupled plasma quadruple mass spectrometry (CRC-ICP-QMS). CRC-ICP-QMS measurements were carried out on discrete samples at a resolution of 1 cm, after dissolution of 150-mg aliquots with 9 ml HNO3 and 1 ml HF at 220 °C in a microwave system. We compare qualitative XRF-CS and quantitative CRC-ICP-MS data and, however the several sources of variability of the data, develop a robust statistical approach to determine the R (2) and the coefficient of a simple regression model together with confidence intervals. Perfect positive correlations were estimated for Cd, Cr, Pb, Sr, Ti and Zn; high positive correlations for Ba (0.8954), Y (0.7378), Fe (0.7349) and Cu (0.7028); while moderate positive correlations for Ga (0.5951) and Ca (0.5435). With our results, we demonstrate that XRF scanning techniques can be used, together with other well-established geochemical techniques (such as ICP-MS), to produce high-resolution (up to 2.5 mm) quantitative data from ombrotrophic peat bog cores.
authors.affiliation: Institute for the Dynamics of Environmental Processes, IDPA/CNR, Dorsoduro 2137, 30123, Venezia, Italy.
authors.forename: Luisa
authors.initials: L
authors.lastname: Poto
authors.forename: Jacopo
authors.initials: J
authors.lastname: Gabrieli
authors.forename: Simon
authors.initials: S
authors.lastname: Crowhurst
authors.forename: Claudio
authors.initials: C
authors.lastname: Agostinelli
authors.forename: Andrea
authors.initials: A
authors.lastname: Spolaor
authors.forename: Warren R L
authors.initials: WR
authors.lastname: Cairns
authors.forename: Giulio
authors.initials: G
authors.lastname: Cozzi
authors.forename: Carlo
authors.initials: C
authors.lastname: Barbante
mesh_terms: D002138:Calibration; D002980:Climate; D004784:Environmental Monitoring / Q000379:methods; D007558:Italy; D057230:Limit of Detection; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D008670:Metals / Q000032:analysis*; D012044:Regression Analysis; D012987:Soil / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission / Q000295:instrumentation / Q000379:methods*
chemical_list: D008670:Metals; D012987:Soil