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Sulfur isotopes are important geochemical tracers in the diverse fields of geosciences. Controlling the accuracy and precision of the microanalysis of sulfur isotopes requires well-characterized reference materials with matrices similar to those of unknown samples. This study introduces a new natural chalcopyrite reference material, TC1725, for S isotope analysis by laser ablation multiple-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS). The chalcopyrite grain is homogeneous with respect to S isotopes based on a large number of measurements by LA-MC-ICP-MS and solution nebulizer (SN)-MC-ICP-MS. Isotope ratio mass spectrometry (IRMS) for S isotopic analysis produced a mean δ34SVCDT value of +12.78 ± 0.16‰ (2 s, n = 11). Results of SN-MC-ICP-MS and LA-ICP-MS analyses are consistent with the IRMS ratios within the uncertainty. A total of 981 sulfur isotope ratio spot measurements conducted on the cruciform sections and randomly selected chalcopyrite grains of TC1725 by LA-MC-ICP-MS yielded highly consistent sulfur isotope ratios. [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]

We prepared a series of pressed powder tablets and chalcopyrite glass standards to correct mass bias when using standard–sample bracketing for in situ sulfur isotope measurements. A femtosecond laser ablation coupled multi-collector inductively coupled plasma mass spectrometry (fsLA-MC-ICP-MS) method was used to determine the sulfur isotope composition of these standards. Chalcopyrite glass (YN411-m) was prepared by quickly quenching the fused chalcopyrite, which was melted at 1000 °C under a protective N2 atmosphere. Multiple experiments were conducted for homogeneity testing of YN411-m by fsLA-MC-ICP-MS and the external precision was 0.28‰ (n = 35). Mineral particles, pressed powder tablets, and chalcopyrite glass were used as bracketing standards when determining the δ34S of a natural chalcopyrite (GC). The results showed that the concentration, elemental composition, and crystal structure caused the matrix effect. Considering practicability, the melted glass was a more appropriate standard than the pressed powder tablet. We also found that the carrier gas flow rate, laser fluence, and spot size impacted the regularity of results. Therefore, we can obtain accurate δ34S by adjusting the laser and MC-ICP-MS parameters when using non-matrix matching standards. Furthermore, fsLA-MC-ICP-MS is advantageous for in situ sulfur isotope measurement because the sensitivity can be improved and it dramatically improves the spatial resolution (10–20 μm), which can be used to explain the origin of multi-genesis deposits by analyzing smaller mineral micro-areas, especially mineral fracture-filling sulfides later in mineralization. [ABSTRACT FROM AUTHOR]