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The sulfur isotope system is important in tracing a variety of geochemical processes. However, the availability of matrix‐matched reference materials for in situ sulfur isotope ratio measurement is limited. This study analysed four sulfide specimens to investigate their potential as reference materials for in situ sulfur isotope determination, including three natural sulfide minerals (sphalerite SPH‐1, chalcopyrite GC‐1 and galena NWU‐GN), and one resin preserved pyrite powder (RPPY). These four sulfides were analysed independently in four laboratories using both bulk and microbeam analysis techniques, all of which gave equivalent results within uncertainty with comparable accuracy and precision. The sulfur isotopes of these four sulfides are homogeneous based on a large number of isotope determinations by solution nebulisation multi‐collector inductively coupled plasma‐mass spectrometry (MC‐ICP‐MS) and laser ablation (LA) MC‐ICP‐MS. The mean δ34S values for SPH‐1, RPPY, GC‐1 and NWU‐GN determined by gas source isotope ratio mass spectrometry (GS‐IRMS) and solution nebulisation MC‐ICP‐MS are −7.13 ± 0.41‰ (2s), 3.66 ± 0.24‰ (2s), −0.65 ± 0.28‰ (2s), 28.21 ± 0.17‰ (2s) relative to the Vienna‐Canyon Diablo troilite (V‐CDT) reference value, respectively, and which are proposed as potential preferred values. Over 400 spot analyses performed on randomly selected fragments of each sulfide by LA‐MC‐ICP‐MS yielded highly consistent δ34S values with the preferred values. Thus, SPH‐1, GC‐1, NWU‐GN and RPPY are considered a set of candidate matrix‐matched sulfide reference materials for in situ sulfur isotope determination. [ABSTRACT FROM AUTHOR]

A new natural chalcopyrite reference material TC1725 is prepared for in situ Cu isotope measurement by femtosecond laser ablation multi‐collector inductively coupled plasma‐mass spectrometry (fsLA‐MC‐ICP‐MS). Detailed textural examination and major element determination suggest the TC1725 chalcopyrite grains have no growth rim or zoning. The chalcopyrite grain is homogeneous with respect to Cu isotopes based on a large number of measurements performed by bulk solution nebuliser (SN)‐MC‐ICP‐MS, single‐grain SN‐MC‐ICP‐MS and fsLA‐MC‐ICP‐MS. The traditional bulk isotope analyses by SN‐MC‐ICP‐MS yielded a mean δ65Cu value of −0.06 ± 0.03‰ (2s, n = 132). Randomly selected single chalcopyrite grain of TC1725 determined by SN‐MC‐ICP‐MS without column chromatography gave a mean δ65Cu value of −0.06 ± 0.04‰ (2s, n = 188). The intermediate measurement precision for four measurement sessions was better than 0.04‰ (2s), suggesting TC1725 chalcopyrite is suitable as a microanalysis reference material for Cu isotope measurement. The mean δ65Cu value determined by fsLA‐MC‐ICP‐MS analyses on different individual chalcopyrite mounts and strips was −0.06 ± 0.03‰ (2s, n = 393), consistent with the bulk isotope composition within uncertainty. The recommended mean δ65Cu value for this chalcopyrite reference material is −0.06 ± 0.03‰ (2s, n = 132) as determined by bulk SN‐MC‐ICP‐MS. [ABSTRACT FROM AUTHOR]