Continuous-flow delta18O measurements: new approach to standardization, high-temperature thermodynamic and sulfate analysis.
The continuous-flow method for the determination of the O-isotope composition of solid samples has significant advantages over off-line extraction methods, but the problem has arisen of the standardization of results that has only partially been resolved by the use of water standards. We propose a new approach to standardization that uses carbothermic reduction of calcium carbonate standards catalyzed by high-purity AgCl. Analytical accuracy, precision, variance homogeneity and long-term stability are proven. Preliminary data on the barium sulfate delta18O analyses are reported, with a closer look at the different results obtained by off-line and on-line methods on intercomparison standards NBS-127 and MSS3.
Boschetti
Tiziano
T
Dipartimento di Scienze della Terra, Università degli Studi di Parma, Parco Area delle Scienze 157/A, 43100 Parma, Italy. tiziano.boschetti@unipr.it
Iacumin
Paola
P
D002482:Cellulose / Q000737:chemistry; D004784:Environmental Monitoring / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006358:Hot Temperature; D007553:Isotope Labeling; D010103:Oxygen Isotopes / Q000032:analysis*; D012015:Reference Standards; D013395:Sucrose / Q000737:chemistry; D013431:Sulfates / Q000737:chemistry*; D013816:Thermodynamics
D010103:Oxygen Isotopes; D013431:Sulfates; D013395:Sucrose; D002482:Cellulose