Determination of Platinum‐Group Elements and Re‐Os Isotopes using ID‐ICP‐MS and N‐TIMS from a Single Digestion after Two‐Stage Column Separation

Abstract

We report an improved procedure for the determination of the platinum-group elements (PGE) and Re, and Os isotopes from a single sample aliquot by isotope dilution (ID) using inductively coupled plasma-mass spectrometry (ICP-MS) and negative thermal ionisation mass spectrometry (N-TIMS), respectively. A two-stage column method was used to purify PGE-Re from their sample matrix and interfering elements (e.g., Mo, Zr and Hf) after Os had been separated by CCl 4 solvent extraction. The first column separation step used cation exchange resin (AG50W-X8) to concentrate PGE-Re and some potential interfering elements (e.g., Mo, Zr and Hf). In the second step, N-benzoyl-N-phenylhydroxylamine (BPHA) extraction resin was used to separate PGE-Re from the remaining interfering elements, which all remained strongly absorbed to the resin. The method was used to determine the PGE and rhenium, and Os isotope ratios in a range of geochemical reference materials (TDB-1, WGB-1, BHVO-2 and UB-N). The obtained results agree well with those previously published. This new method enables PGE-Re abundances and Os isotopic ratios to be determined on the same sample digestion, and circumvents the problems created by sample heterogeneity when comparing PGE and Re-Os isotope data.

Os–Nd–Sr isotopes in Miocene ultrapotassic rocks of southern Tibet: Partial melting of a pyroxenite-bearing lithospheric mantle?

“…Repeat analyses of the ultrapotassic rocks in the two laboratories show consistent results. The details of the analytical procedures are described by Li et al (2010Li et al ( , 2014 and Xu et al (2007).…”

Disequilibrium-induced initial Os isotopic heterogeneity in gram aliquots of single basaltic rock powders: Implications for dating and source tracing

“…Mass spectrometry procedures for the Os are given in Li et al (2014Li et al ( , 2015. Os was loaded onto Pt filaments and measured as OsO 3 − ions by negative-thermal ionization mass spectrometry (N-TIMS) using the electron multiplier mode on a Thermo-Finnigan Triton (Creaser et al, 1991;Volkening et al, 1991) Os value of 0.1202 ± 3 (2 SD, n = 12) for the period of analysis.…”

“…Several recent studies have conducted replicate Re-Os isotope analyses of individual powders (~200 mesh in size) of mafic-ultramafic rocks (Meisel et al, 2001;Ishikawa et al, 2014;Li et al, 2014). In these studies, replicate analyses of each sample defined a good apparent isochron; the derived apparent isochron ages and initial Os isotopic compositions were used to constrain the timing of geological events and to trace the characteristics of mantle sources (Meisel et al, 2001;Ishikawa et al, 2014;Li et al, 2014).…”

“…In these studies, replicate analyses of each sample defined a good apparent isochron; the derived apparent isochron ages and initial Os isotopic compositions were used to constrain the timing of geological events and to trace the characteristics of mantle sources (Meisel et al, 2001;Ishikawa et al, 2014;Li et al, 2014). In light of the nugget effect for both Re and Os concentrations, it is possible that the Os isotopic compositions of individual hand-specimen samples were not totally homogenized when the rocks formed.…”

Re-Os pyrite geochronology of Zn-Pb mineralization in the giant Caixiashan deposit, NW China

“…Peak hopping with short dwell times of 30 ms (measurement time on peak) was undertaken to provide quasi-simultaneous measurement. The details of the ICP-MS analyses are described elsewhere (Li et al 2014a). Total procedural blanks (TPB) for this technique were 0.32 ± 0.14 pg with the 187 Os/ 188 Os ratio of 0.284 ± 0.049 (n = 6, 1 s) on average for Os and between 6 and 8 pg for Re.…”