δ2H is measured in solids including vegetation, biological tissues, and hydrated silicas using a Thermo TC/EA interfaced with a ConFlo III and Thermo Finnigan DELTAplus XP IRMS.
Dried, homogenized* samples are weighed into furnace- or oven-baked silver capsules†. Samples are dropped sequentially by a zero-blank (helium-flushed) autosampler into a glassy carbon reactor and thermally converted at 1450 °C. Sample gases are swept on a stream of ultra high purity (99.999% pure) helium to a 0.6 meter packed gas-chromatographic column to separate sample H2, N2, and CO, then introduced into the IRMS via ConFlo III for measurement against an H2 reference gas.
Final δ2H values are expressed in permil relative to the Vienna Standard Mean Ocean Water (VSMOW) scale. Long-term standard deviation of δ2H measurements, as assessed by repeated analyses of blind standards, is better than 0.2 permil.
Typical sample size: 0.1 to 0.4 mg
Chesson LA, Podlesak DW, Cerling TE, Ehleringer JR. 2009. Evaluating uncertainty in the calculation of non-exchangeable hydrogen fractions within organic materials. Rapid Communications in Mass Spectrometry 23: 1275-1280.
Martin E, Bindeman I, Balan E, Palandri J, Seligman A, Villemant B. 2017. Hydrogen isotope determination by TC/EA technique in application to volcanic glass as a window into secondary hydration. Journal of Volcanology and Geothermal Research 348: 49-61.
Seligman AN, Bindeman IN, Watkins JM, Ross AM. 2016. Water in volcanic glass: from volcanic degassing to secondary hydration. Geochimica et Cosmochimica Acta 191: 216-238.
Wassenaar LI, Hobson KA. 2003. Comparative equilibration and online technique for determination of non-exchangeable hydrogen of keratins for use in animal migration studies. Isotopes in Environmental and Health Studies 39(3): 211-217.
δ18O is measured in solids including vegetation, biological tissues, nitrates, sulfates, and phosphates using a Thermo TC/EA interfaced with a ConFlo III and Thermo Finnigan DELTAplus XP IRMS. Measurement of δ18O in silicates is also possible using a fluorinating agent to release oxygen from the sample.
Same as the δ2H method described above. Because residual phosphate interferes with the measurement of sulfate oxygen, we use separate reactors for each material.
Final δ18O values are expressed in permil relative to Vienna Standard Mean Ocean Water (VSMOW). Long-term standard deviation of δ18O measurements, as assessed by repeated analyses of blind standards, is better than 0.2 permil.
Typical sample size: 0.2 to >2 mg
Bӧhlke JK, Mroczkowski SJ, Coplen TB. 2003. Oxygen isotopes in nitrate: new reference materials for 18O:17O:16O measurements and observations on nitrate-water equilibration. Rapid Communications in Mass Spectrometry 17: 1835-1846.
Boschetti T, Iacumin P. 2005. Continuous-flow δ18O measurements: new approach to standardization, high-temperature thermodynamic and sulfate analysis. Rapid Communications in Mass Spectrometry 19: 3007-3014.
LaPorte DF, Holmden C, Patterson WP, Prokopiuk T, Eglington BM. 2009. Oxygen isotope analysis of phosphate: improved precision using TC/EA CP-IRMS. Journal of Mass Spectrometry 44: 879-890.
Lécuyer C, Fourel F, Martineau F, Amiot R, Bernard A, Daux V, Escarguel G, Morrison J. 2007. High-precision determination of 18O/16O ratios of silver phosphate by EA-pyrolysis-IRMS continuous flow technique. Journal of Mass Spectrometry 42: 36-41.
Menicucci AJ, Spero HJ, Matthews J, Parikh SJ. 2017. Influence of exchangeable oxygen on biogenic silica oxygen isotope data. Chemical Geology 466: 710-721.
Webb EA, Longstaffe FJ. 2002. Climatic influences on the oxygen isotopic composition of biogenic silica in prairie grass. Geochimica et Cosmochimica Acta 66(11): 1891-1904.
†Samples should be homogenized prior to shipment. If this is not possible, samples can be homogenized at KSIGL. Please see the pricing tab for current rates.
‡Samples can be shipped in individual containers and weighed into tin capsules at KSIGL by trained technician. Please see the pricing tab for current rates.