Preparation, characterization, and value assignment of carbon dioxide isotopic reference materials: RMs 8562, 8563, and 8564
Preparation, characterization, and value assignment of carbon dioxide isotopic reference materials: RMs 8562, 8563, and 8564
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DOI：
10.1021/ac990233c
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发表时间：
1999-10-15
影响因子：
7.4
通讯作者：
Verkouteren, RM
中科院分区：
文献类型：
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作者：
Verkouteren, RM
制备了三种二氧化碳同位素标准物质（RM 8562、RM 8563和RM 8564），并使用双入口同位素比质谱法对其组成、非均质性和稳定性进行了表征，RM 8562-8564尚未获得认证，但它们作为碳酸盐标准物的替代品，使用户可以精确地实现维也纳PDB标度，并提供不同实验室研究人员获得的稳定碳氧同位素比数据的可比性。样品（每个样品约400mu mol）密封在硼硅玻璃管（外径9mm）中，由美国国家标准与技术研究院（NIST）和国际原子能机构（IAEA）分发。CO2均数的δ (13)C和δ (18)O值分配和不确定性由两种互补的方法确定：(1)通过国际比较，允许单点标准化到VPDB尺度上；(2)通过同位素验证的相对（δ δ）值测量均数(δ δ (45)CO(2)、δ δ (46)CO(2)和δ δ (47)CO(2))。相互比较工作涉及13个国际实验室；测量用碳酸盐和其他均方根归一化。Delta δ值是在NIST测量的，仪器设计和测量方案允许δ (45)CO(2)、δ (46)CO(2)和δ (47)CO(2)的同位素一致性测定，这是测量精度的必要条件。赋值(和结合标准的不确定性)(13)C (VPDB)和δ(18)O (VPDB)值,分别为-3.76‰部分(0.03‰部分)和-8.45‰(RM 0.11‰部分)8562年,千分之-41.56部分(0.06‰部分)和-23.72‰(0.11‰部分)RM 8563和-10.45‰(0.04‰部分)和+ 0.19‰(RM 0.10‰部分)8564。在任何批次（每个批次由超过1000个样品组成）中，测量到δ (13)C和δ (18)O的样品间同位素变化（标准差）分别小于0.007‰和0.026‰。经过两年的监测，没有观察到这些区域长期同位素漂移的确凿证据。
Three carbon dioxide isotopic reference materials (RM 8562, RM 8563, and RM 8564) have been prepared and characterized for composition, heterogeneity, and stability using dual-inlet isotope ratio mass spectrometry, RMs 8562-8564 are not certified, but their use as proxies for carbonate standards allows users to realize precisely the Vienna PDB scale and to provide comparability of stable carbon and oxygen isotope ratio data obtained by investigators in different laboratories. Samples (similar to 400 mu mol each) are sealed in borosilicate glass tubes (9-mm outer diameter) for distribution by the National Institute of Standards and Technology (NIST) and the International Atomic Energy Agency (IAEA). delta(13)C and delta(18)O value assignments and uncertainties for the CO2 RMs were determined by two complementary methods: (1) through an international comparison exercise, to allow single-point standardization onto the VPDB scale and (2) through isotopically verified measurements of relative (Delta delta) values between RMs (Delta delta(45)CO(2), Delta delta(46)CO(2), and Delta delta(47)CO(2)). The intercomparison exercise involved thirteen international laboratories; measurements were normalized by carbonate and other RMs. The Delta delta values were measured at NIST, where instrument design and measurement protocols allowed isotopically consistent determinations of delta(45)CO(2), delta(46)CO(2), and delta(47)CO(2), a necessary condition of measurement accuracy. The value assignments (and combined standard uncertainties) for the delta(13)C(VPDB) and delta(18)O(VPDB) values are, respectively, -3.76 parts per thousand (0.03 parts per thousand) and -8.45 parts per thousand (0.11 parts per thousand) for RM 8562, -41.56 parts per thousand (0.06 parts per thousand) and -23.72 parts per thousand (0.11 parts per thousand) for RM 8563, and -10.45 parts per thousand (0.04 parts per thousand) and +0.19 parts per thousand (0.10 parts per thousand) for RM 8564. Within any batch (each consisting of over 1000 samples), sample-to-sample isotopic variations (standard deviations) were measured to be less than 0.007 parts per thousand and 0.026 parts per thousand for delta(13)C and delta(18)O, respectively. No conclusive evidence of long-term isotopic drift in these RMs has been observed after two years of monitoring.