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Stable nickel (Ni) isotopes have shown great potential for investigating planetary accretion processes, mantle–crust magmatism, and paleo-marine evolution. The development of an economical and time-efficient separation method for Ni isotope analysis holds significant value within the realm of Ni isotope research. Previous purification methods for Ni isotope analysis have typically relied on either multi-column procedures or the utilization of significant quantities of organic reagents, such as acetic acid, acetone, and dimethylglyoxime. In this study, a novel two-column chromatographic separation procedure was presented for the determination of Ni isotope compositions in geological materials. A cation resin (AG50W-X8) was utilized in conjunction with diluted HCl and HF to effectively remove a substantial portion of matrix elements. Subsequently, trace amounts (100–200 μL) of Ni-spec resin were used for further purification of Ni. This relatively simple purification scheme for Ni isotope analysis effectively reduces the use of organic reagents and the amount of Ni-spec resin compared to previous methods that relied on multi-column separation and organic reagent extraction. Ni isotopic compositions were analyzed using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The instrumental mass discrimination of Ni isotopic ratios was corrected for using the double spike (DS) combined with the sample–standard bracketing (SSB) method. The Ni isotope compositions (δ60Ni) of in-house standards (SCP and CUG) were −0.06 ± 0.05‰ (2 SD, n = 104) and 0.36 ± 0.06‰ (2 SD, n = 97), respectively. Furthermore, the measured δ60Ni values of various geological reference materials (BCR-2, BHVO-2, BIR-1, DTS-1, DTS-2b, SDO-1, GSP-2, and W-2a from the USGS; JB-1b from the GSJ; GSR-2, GSR-3, GSR-4, GSR-5, and GSR-10 from the NRCGA) were consistent with previous studies within measurement error. Additionally, the δ60Ni values of AGV-1 from the USGS, as well as those of GSR-10, GSR-12, GSR-15, GSR-17, GSR-18, and GSR-19 from the NRCGA are reported here for the first time. Based on repeated measurements of pure solutions and reference materials, the long-term reproducibility of δ60Ni values was better than ± 0.06‰ (2 SD). Consequently, our study presents a relatively straightforward purification method for Ni for its isotopic analysis using only trace amounts of organic reagents and Ni-spec resin. [ABSTRACT FROM AUTHOR]

In this study, a novel lithium metaborate fusion technique using a homemade fusion furnace and graphite crucibles was developed to produce homogeneous glasses from silicate rock powder. The glasses were then analyzed for both major and trace element concentrations by LA-ICP-MS. The parameters of the ratio of flux-to-sample, melting temperature and time, and closed fusion were optimized. It was found that homogeneous glasses could be obtained, and the loss of Pb was effectively suppressed at a low melting temperature and short time (900 or 950 °C for 5 min) in closed fusion. Compared to Pt or Pt–Au crucibles in the traditional flux fusion method, homemade graphite crucibles are more economical and omit the need of any releasing agent because the bottom curve design allows the melt to shrink into a bead for easy removal. Accurate results by LA-ICP-MS can be directly obtained by applying a quantitative calibration strategy using 100% oxide normalization, which offers a solution for unknown sample analysis without the prior determination of the concentration of an internal standard element. The analytical results of 42 major and trace elements in 5 USGS silicate rock reference materials (covering mafic to felsic rock types) using the developed LiBO2 fusion technique are consistent with the reference values within 10% for most elements, and analytical precision (RSD) is within 10% for most elements. The developed method is simple for preparing homogeneous glasses from rock powders, which displays great potential for the rapid and accurate determination of mass fractions of major and trace elements in silicate rocks using LA-ICP-MS. [ABSTRACT FROM AUTHOR]

The origin of crystal‐scale Zr isotopic variation remains enigmatic. Here, we report high‐precision Zr isotopic compositions of thin‐sectioned and hand‐picked zircon crystals from monzodiorites and K‐feldspar granites, which represent the mafic and felsic products of a differentiating magma. Our results reveal that zircons from both rock associations are dominated by a rim‐ward increase in the 94Zr/90Zr ratio and accompanied by ∼1‰ intracrystalline and intercrystalline variations, confirming the preferential incorporation of light Zr isotopes and thus kinetic isotopic fractionation during zircon growth. Notably, zircons enclosed by K‐feldspar in monzodiorites generally yield lower 94Zr/90Zr and higher Zr/Hf ratios than that of separated crystals, while in K‐feldspar granites, tiny zircons intergrown with apatite obtain higher 94Zr/90Zr but lower Zr/Hf ratios relative to that of sizable separates. The diversity in petrographic textures and sizes of zircon crystals, corresponding to their crystallization sequence, potentially accounts for some of the heterogeneity of Zr isotopes at the mineral scale. Plain Language Summary: Stable Zr isotopes of zircon have been proposed as a new and promising tracer for magmatic differentiation. However, how significant heterogeneity of Zr isotopes developed at the mineral scale in an evolving magma is highly debatable. Ab initio simulation calculations, experiments, and natural sampling have suggested that kinetic rather than equilibrium effect plays a dominant role in fractionating Zr isotopes during zircon crystallization, whereas how kinetic effect links with the textural contexts of zircons is not directly constrained. Here, petrographic and geochemical constraints on zircon crystals from the mafic and felsic products of a differentiating magma are provided, which reveal that earlier crystallized domains or crystals are isotopically lighter in Zr than the later ones. Besides, the δ94Zr values of zircon crystals, displaying intra‐grain and inter‐grain variations beyond ∼1‰, correlate well with Zr/Hf ratios that reflect diverse stages of magma differentiation, irrespective of the compositions of host rocks. These findings indicate that crystal‐scale elemental and stable isotopic variations (e.g., Zr isotopes in zircon) could be ascribed to the sequential crystallization of targeting minerals. Key Points: Early‐formed zircon crystals or domains are isotopically lighter in Zr than those crystallized late in both mafic and felsic rocksDiversity in textural occurrences and sizes of zircons potentially explain the Zr isotopic heterogeneity at the mineral scaleGeochemical information extracted from separated minerals does not always reflect the nature of primitive magma [ABSTRACT FROM AUTHOR]

Silver (Ag) is a trace metal element in geological rocks and accurate determination of its abundance is very challenging given significant oxide and hydroxide interferences from Zr, Nb, Mo, and Y. Here, we developed a valid method based on inductively coupled plasma-tandem mass spectrometry (ICP-MS/MS), in which NH3 was used as the reaction gas, to determine the Ag content in geological samples. The additional quadrupole analyzer located in front of the collision/reaction cell ensured a simple and controllable reaction in the cell. The first quadrupole (Q1) was set to m/z 107 and 109 to allow Ag+ and its interferences to enter the reaction cell. Ag+ partially reacted with NH3, forming Ag+ and Ag(NH3)2+ as the main products; while the major interferences, ZrO+ and NbO+, reacted strongly and were converted to ZrO(NH3)4+, ZrO(NH3)5+, and NbO(NH(NH3)3)+, respectively, and thus no longer affected the measurement of Ag. Consequently, the Ag signals could be detected by both "on-mass" and "mass-shift" methods, where the m/z of Q1–Q2 were 107–107, 109–109 and 107–141, 109–143, respectively. Under the optimized NH3 flow rate (3.5 ml min−1), the interference levels of the matrix solution (0.3 μg ml−1 Zr and Mo, 0.2 μg ml−1 Zn, 0.1 μg ml−1 Y and Nb, and 0.05 μg ml−1 Ga) in four Q1–Q2 mass pairs were negligible and comparable to background signals, and the limits of detection of geological samples were <0.53 ng g−1. The Ag content of 19 geological reference materials was reported using the proposed ICP-MS/MS method, and the results were consistent with isotope dilution-ICP-MS values. Thus, the proposed method has great potential for the accurate, direct, and high-throughput measurement of Ag in geological samples. [ABSTRACT FROM AUTHOR]