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Separation of Platinum from Palladium and Iridium in Iron Meteorites and Accurate High‐Precision Determination of Platinum Isotopes by Multi‐Collector ICP‐MS
Author(s) -
Hunt Alison C.,
Ek Mattias,
Schönbächler Maria
Publication year - 2017
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.12176
Subject(s) - platinum , meteorite , palladium , iron meteorite , isotope , iridium , analytical chemistry (journal) , inductively coupled plasma mass spectrometry , chemistry , elution , ascorbic acid , accuracy and precision , radiochemistry , materials science , chromatography , mass spectrometry , physics , biochemistry , food science , quantum mechanics , astronomy , catalysis
This study presents a new measurement procedure for the isolation of Pt from iron meteorite samples. The method also allows for the separation of Pd from the same sample aliquot. The separation entails a two‐stage anion‐exchange procedure. In the first stage, Pt and Pd are separated from each other and from major matrix constituents including Fe and Ni. In the second stage, Ir is reduced with ascorbic acid and eluted from the column before Pt collection. Platinum yields for the total procedure were typically 50–70%. After purification, high‐precision Pt isotope determinations were performed by multi‐collector ICP‐MS. The precision of the new method was assessed using the IIAB iron meteorite North Chile. Replicate analyses of multiple digestions of this material yielded an intermediate precision for the measurement results of 0.73 for ε 192 Pt, 0.15 for ε 194 Pt and 0.09 for ε 196 Pt (2 standard deviations). The NIST SRM 3140 Pt solution reference material was passed through the measurement procedure and yielded an isotopic composition that is identical to the unprocessed Pt reference material. This indicates that the new technique is unbiased within the limit of the estimated uncertainties. Data for three iron meteorites support that Pt isotope variations in these samples are due to exposure to galactic cosmic rays in space.