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A Matrix‐Matched Reference Material for Validating Petroleum Re‐Os Measurements
Author(s) -
Liu Junjie,
Selby David
Publication year - 2018
Publication title -
geostandards and geoanalytical research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.037
H-Index - 73
eISSN - 1751-908X
pISSN - 1639-4488
DOI - 10.1111/ggr.12193
Subject(s) - asphaltene , fraction (chemistry) , chemistry , analytical chemistry (journal) , homogeneous , isotope , isotope dilution , matrix (chemical analysis) , mass fraction , mass spectrometry , petroleum , chromatography , thermodynamics , organic chemistry , physics , quantum mechanics
This study presents two matrix‐matched reference materials developed for petroleum Re‐Os measurements. We present the Re and Os mass fractions and 187 Re/ 188 Os and 187 Os/ 188 Os values (ratio of the number of atoms of the isotopes) for repeatedly measured aliquots ( ca . 120–150 mg test portions) of the NIST Research Material 8505 ( RM 8505) crude oil, and its asphaltene and maltene fractions, and ~ 90 g of homogeneous asphaltene powder isolated from this oil. Measurements were performed using the Carius tube‐isotope dilution negative‐thermal ionisation mass spectrometry methodology. The RM 8505 crude oil contains 1.98 ± 0.07 ng g −1 Re and 25.0 ± 1.1 pg g −1 Os, with Re‐Os isotope amount ratios of 452 ± 6 for 187 Re/ 188 Os and 1.51 ± 0.01 for 187 Os/ 188 Os ( n = 20, 95% conf.). The homogeneous asphaltene sample contains 16.52 ± 0.10 ng g −1 Re and 166.0 ± 0.9 pg g −1 total Os, and possesses isotope amount ratios of 574 ± 3 for 187 Re/ 188 Os and 1.64 ± 0.01 for 187 Os/ 188 Os ( n = 24, 95% conf.). The intermediate precision of these data makes the RM 8505 whole oil and the (~ 90 g) homogenised asphaltene appropriate petroleum matrix‐matched reference materials for Re‐Os measurements. The asphaltene fraction of the oil is the main carrier of Re and Os of the RM 8505 whole oil, and caution is suggested in using asphaltene and maltene fractions of a single oil for Re‐Os geochronology.