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Thallium Mass Fraction and Stable Isotope Ratios of Sixteen Geological Reference Materials
Author(s) -
Brett Alex,
Prytulak Julie,
Hammond Samantha J.,
Rehkämper Mark
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.12215
Subject(s) - thallium , isotope , mass fraction , analytical chemistry (journal) , fraction (chemistry) , stable isotope ratio , mica , chemistry , mineralogy , radiochemistry , materials science , environmental chemistry , chromatography , metallurgy , physics , nuclear physics , inorganic chemistry , organic chemistry
Thallium stable isotope ratio and mass fraction measurements were performed on sixteen geological reference materials spanning three orders of magnitude in thallium mass fraction, including both whole rock and partially separated mineral powders. For stable isotope ratio measurements, a minimum of three independent digestions of each reference material was obtained. High‐precision trace element measurements (including Tl) were also performed for the majority of these RM s. The range of Tl mass fractions represented is 10 ng g −1 to 16 μg g −1 , and Tl stable isotope ratios (reported for historical reasons as ε 205 Tl relative to NIST SRM 997) span the range −4 to +2. With the exception – attributed to between‐bottle heterogeneity – of G‐2, the majority of data are in good agreement with published or certified values, where available. The precision of mean of independent measurement results between independent dissolutions suggests that, for the majority of materials analysed, a minimum digested mass of 100 mg is recommended to mitigate the impact of small‐scale powder heterogeneity. Of the sixteen materials analysed, we therefore recommend for use as Tl reference materials the USGS materials BCR ‐2, COQ ‐1, GSP ‐2 and STM ‐1; CRPG materials AL ‐I, AN ‐G, FK ‐N, ISH ‐G, MDO ‐G, Mica‐Fe, Mica‐Mg and UB ‐N; NIST SRM 607 and OREAS 14P.