Title : High precision analysis of oxygen three isotopes in silicates by
DI IRMS with a CO 2 laser BrF 5 fluorination technique
Abstract : An infrared laser BrF 5 fluorination method coupled with dual inlet
isotope ratio mass spectrometer is widely used as a fundamental system for oxygen extraction from silicate samples and can perform most precise oxygen three isotope analysis. O 2 liberated from silicate sample (~2 mg) by laser fluorination is purified using cryogenic technique in vacuum line. The 17 O/ 16 O and 18 O/ 16 O ratios of the extracted O 2 are measured with the mass spectrometer. The analytical precisions (1σ) for δ 18 O and Δ' 17 O values of standard samples (UWG2 garnet, NBS28 quartz, San Carlos olivine and in house obsidian) are better than 0.1‰ and 11 ppm respectively. Furthermore, analysis of the VSMOW (Vienna Standard Mean Ocean Water) and SLAP (Standard Light Antarctic Precipitation) reference water is underway to achieve high accuracy. The two point normalization using these reference waters is expected to provide us with an improved determination of oxygen isotope ratio in silicates.
The precise determination of the oxygen three isotope compositions in silicate materials is important to understand the geochemical processes related to their origin and secondary effects. High precision oxygen isotope analysis can provide understanding for isotopic heterogeneity of terrestrial silicates. Recent studies focus on the variation of Δ' 17 O of rocks because of the high levels of precision. Here, I introduce the analytical system of oxygen three isotope and potential applications to oxygen isotope fractionation.
회의 ID: 369-505-0171