Hydrogen and D/H analysis of apatite by Elemental Analyzer-Chromium/High-Temperature Conversion-Isotope Ratio Mass Spectrometry (EA-Cr/HTC-IRMS)
Hydrogen and D/H analysis of apatite by Elemental Analyzer-Chromium/High-Temperature Conversion-Isotope Ratio Mass Spectrometry (EA-Cr/HTC-IRMS)
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DOI：
10.1016/j.chemgeo.2018.09.029
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发表时间：
2018-11-15
期刊：
影响因子：
3.9
通讯作者：
Greenwood, James P.
中科院分区：
文献类型：
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作者：
Greenwood, James P.
氢和矿物磷灰石的Δ D测量已被用于测量行星和微行星的挥发性含量，并推断整个太阳系中水的来源和演化。所有这些研究都使用二次离子质谱法（西姆斯），这需要使用磷灰石矿物标准来校正基质效应，而基质效应以前是通过氢同位素质谱法测量的。本文介绍了一种新的元素分析仪-铬/高温转化-同位素比值质谱（EA-Cr/HTC-IRMS）技术，用于磷灰石的氢和氢同位素的测定。由于铬在高温反应器中与磷结合的能力，该技术比TC/EA具有更大的技术优势，并防止这种元素P堵塞仪器部件。我们还表明，名义上含水矿物和玻璃的吸附水分的去除变得越来越重要，随着材料的晶粒尺寸的减小，目前的实验从名义上无水石英的水分去除。我们报告的氢和氢同位素结果的五个氟磷灰石和两个羟基磷灰石样品，包括杜兰戈磷灰石。我们表明，我们的杜兰戈磷灰石的氢含量的结果是类似的使用TC/EA技术发表的值。对于H2O，我们使用Cr反应器的氢推荐值为608 +/- 102 ppm H2O，对于Durango磷灰石，Δ DVSMOW-Score = - 86 +/- 4%（2 sigma）。
Hydrogen and delta D measurements of the mineral apatite have been used to measure volatile contents of planets and planetesimals and to infer the sources and evolution of water throughout the solar system. All of these studies use Secondary Ion Mass Spectrometry (SIMS) which necessitates the use of apatite mineral standards to correct for matrix effects, which have previously been measured by mass spectrometry for hydrogen isotopes. Here we present a new technique of Elemental Analyzer-Chromium/High Temperature Conversion-Isotope Ratio Mass Spectrometry (EA-Cr/HTC-IRMS) for the measurement of hydrogen and hydrogen isotopes of apatite. This technique presents greater technical advantages over TC/EA due to ability of chromium to bind with phosphorus in the high-temperature reactor, and prevent this elemental P from clogging the instrument components. We also show that removal of adsorbed moisture of nominally hydrous minerals and glasses becomes increasingly important with decreasing grain size of materials and present experiments on moisture removal from nominally anhydrous quartz. We report hydrogen and hydrogen isotope results of five fluorapatite and two hydroxylapatite samples, including Durango apatite. We show that our results of hydrogen content of Durango apatite are similar to published values using the TC/EA technique. Our recommended values for hydrogen using a Cr reactor for H2O and delta DVSMOW-SLAP for Durango apatite are 608 +/- 102 ppm H2O and delta DVSMOW-SLAP = - 86 +/- 4% (2 sigma).