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In this study, data from thirteen laboratories from around the world are presented for a successful certification of uranium isotope ratios in uranium ore concentrate (UOC) certified reference materials from the National Research Council Canada. Different mass spectrometric measurement principles (including SF-ICP-MS, quadruple ICP-MS, TIMS, MC-ICP-MS, SIMS and AMS) and measurement procedures were employed. In general, data from all sources exhibit good consistency with TIMS and MC-ICP-MS showing superior performance. The three candidate UOC CRMs (UCLO-1, UCHI-1 and UPER-1) have natural uranium isotope ratios with certified values of 0.5304(7) × 10⁻⁴, 0.5475(2) × 10⁻⁴ and 0.5361(4) × 10⁻⁴ for n(²³⁴U)/n(²³⁸U) and 0.007 2563(13), 0.007 2563(10) and 0.007 2542(11) for n(²³⁵U)/n(²³⁸U), respectively, with expanded uncertainty (k = 2) applicable to the last digit of the value given in the parentheses. Information values for n(²³⁶U)/n(²³⁸U) in these three CRMs, measured by AMS, are also provided: 10 × 10⁻¹², 200 × 10⁻¹² and 22 × 10⁻¹². The uncertainties of the proposed certified values of uranium isotope ratios in UOC CRMs are superior to available reference materials, and the values of n(²³⁴U)/n(²³⁸U) and n(²³⁶U)/n(²³⁸U) show significant variation among the three CRMs.

Vanadium isotope compositions (δ(51V)) in marine carbonates are a potential proxy to trace global redox states of ancient oceans. Although high-precision δ(51V) analyses are available for many geol...

National Key Research and Development Programme of China [2017YFC0601302]; National Natural Science Foundation of ChinaNational Natural Science Foundation of China (NSFC) [91755206, 41972056, 41622202]

Removing interferences such as Ce on Nd isotopes during column chemistry is hard to achieve due to their similar properties. In this study, we established a simple but efficient Nd separation technique with the perfect separation of Nd from Ce and nearly 100% Nd yield using the TODGA resin (50–100 μm, Eichrom, USA) after actual measurements. All samples used here through the Nd separation technique have Ce/Nd ratios less than 0.003. The whole procedure takes about 10 h. The stable Nd isotopes were measured by MC-ICP-MS and calibrated with standard-sample-standard bracketing (SSB) combined Eu internal normalization. The potential influences of Eu and Ce on stable Nd isotopic analysis were strictly evaluated. The long-term analyses of the JNdi-1 standard produced a total average δ142/144Nd of 0.000 ± 0.029‰ (2SD, n = 210), δ145/144Nd of 0.000 ± 0.029‰ (2SD, n = 210), and δ146/144Nd of 0.000 ± 0.027‰ (2SD, n = 210). Two pure Nd standards, La Jolla and Nd-GIG, produced δ146/144Nd values (means ± 2SD, n = 20) of −0.227 ± 0.030‰ and 0.226 ± 0.021‰, respectively. δ146/144Nd (means ± 2SD, n = 20) of seven geological reference materials (BCR-1, BHVO-2, AGV-2, GSP-2, NOD-P-1, NOD-A-1, and GBW07249) were also reported. The reproducibility of δ146/144Nd was better than 0.030‰. These results are in good agreement with the published DS-TIMS methods. In addition, our method also allows the concurrent determination of the radiogenic 143Nd/144Nd ratio. All the 143Nd/144Nd ratios of these samples are identical with the preferred values published in the GeoReM Database. These results indicated that the method of Nd isotopic analysis established here can simultaneously measure high-precision δ142/144Nd, δ145/144Nd, δ146/144Nd, and radiogenic 143Nd/144Nd ratio for geological materials.

The boron isotopic ratio (δ11B) of marine biogenic carbonates is a proxy for ocean pH through the geological times, provided that δ11B measurements reach precisions better than 0.8‰ (2 SD), corresponding to 0.1 pH-unit (magnitude of the Anthropocene ocean acidification). This level of precision is however challenging to achieve for samples with a small size and low B content used in paleoceanographic reconstructions. We developed a protocol combining (i) the fast-handling and very low blank (9 ± 7 pg, 1 SD, n = 7) microsublimation technique to purify boron from the carbonate matrix and (ii) the direct injection of the samples into the MC-ICP-MS plasma with the new μ-dDIHEN device, allowing for small sample volumes and low uptake rates. We further used Jet sampler and X skimmer cones and implemented two 1013 Ω amplifiers to respectively increase the sensitivity and enhance the signal/noise ratio, enabling the precise measurement of small B signals. Our protocol, that consumes only 240 μL for one triplicate sample-standard bracketing (SSB) measurement, was validated through repeated B extractions and measurements of the carbonate reference material MVS-1 at different B concentrations. It yielded 15.93 ± 0.24‰ (2 SD, n = 10) with only 1.2 ng consumed for one triplicate SSB measurement, with individual external repeatabilities (n = 5, 2 SD) of 0.19 ± 0.14‰. We further measured δ11B of modern biogenic carbonates (arthropods, brachiopods, molluscs, red algae and reef carbonate mixes) down to 0.5–0.7 ng of B and successfully compared these δ11B values with those obtained after B extraction of the same samples through ion exchange chromatography.

Due to their relatively high Hf contents (i.e., several hundreds to thousands of ppm), columbite-group minerals (CGMs) are suitable for Lu–Hf isotope analysis, which can provide new insights into the source of such minerals in combination with the U–Pb age of rare-metal deposits. However, few studies have reported Lu–Hf isotope data for CGMs. Tantalum is a major element in CGMs (12–48 wt% Ta2O5) and has a significant effect on measurements of Hf isotopes using MC-ICP-MS. This effect was first evaluated in this study by analysis of mixed Hf–Ta standard solutions with different Ta/Hf ratios and LA-MC-ICP-MS analysis of various CGMs. This analytical artifact reflects serious tailing of the large 181Ta signal onto the 180Hf and 179Hf masses during analysis. Therefore, in order to obtain accurate Hf isotope data for CGMs by MC-ICP-MS, we present an improved chemical separation procedure for Hf from Ta, and also a novel analytical protocol for LA-MC-ICP-MS analysis of CGMs. Accurate in situ176Hf/177Hf ratios for CGMs can be obtained by normalization to 178Hf/177Hf = 1.4672, rather than 179Hf/177Hf = 0.7325, using the exponential law. This approach was validated by solution and laser ablation MC-ICP-MS analysis of four CGM samples from China and Africa. The Lu–Hf isotopic composition of CGMs provides a new geochemical tracer for rare-metal deposits.

The development of collision-cell multi-collection inductively-coupled-plasma mass-spectrometers has revolutionized K isotope chemistry, improving the sensitivity by over a factor of 10 compared to that of older generation instruments. The application of isotope chemistry of metals in medical science (isotope metallomics) has shown significant growth in the last few years with respect to the study of metal cycles in the body and/or as diagnostic tools for diseases affecting metal homeostasis. Given the major role that K plays in biology through the preservation of cellular homeostasis itself, the generation of nervous impulses, and the formation of glycogen in the liver, the development of K isotope metallomics is imminent and necessary. To this end, we report the first set of high precision K isotopic data for numerous widely available biological reference materials, spanning both land and sea animals, as well as various bodily organs (muscle, kidneys, and liver). Results indicate that land animals are globally enriched in the lighter isotopes compared to sea animals, and that K isotopes are fractionated by more than 1.5‰ between organs (bovine), highlighting that K isotopes could be used to study K cycles within the body. These novel data—and reference materials—could be used for future interlaboratory comparisons.

Cu isotopic analysis can provide valuable insight when investigating Wilson's disease (WD), but one of the problems related to this type of study is that usually low sample volumes are available and/or low Cu concentrations are found in these samples. This paper presents a new approach for Cu isotope ratio determination that requires only 1 μL of pre-treated serum sample per replicate (after Cu separation and preconcentration to a Cu concentration range between 0.3 and 4 mg L−1). Cu determination was carried out by direct μ-injection of 1 μL of pretreated serum samples into an ICP-MS, offering a LOD of 3 μg L−1. For Cu isotopic analysis, the method presented is based on micro-volume deposition on a pure silicon wafer and subsequent ablation analysis by fsLA-MC-ICP-MS. Cu isotopic analysis of NIST 3114 at 1 mg L−1 Cu concentration with the self-bracketing method provided average δ65Cu values of −0.01 ± 0.19‰ (2SD) and an internal precision value of 517 ppm. This method was deployed for the analysis of serum samples from WD patients under different treatments, as well as healthy newborns and patients with other liver disorders. The results seem to link decreased δ65Cu values to Cu release from the liver, further demonstrating the potential of this type of analysis in the biomedical context.

A new simple and rapid method was developed for the purification of Mg from carbonate samples, especially for calcite-rich carbonates. The proposed separation protocol consists of only two types of eluents (4 mol l−1 HNO3 and deionized water) based on 2 ml of DGA resin. 4 ml of HNO3 can effectively separate Mg from calcite-rich carbonates with a high yield within one hour. The Mg elution curve would not drift with different Mg and Ca loading onto the DGA resin. Ca/Mg ratios of the purified samples could be reduced by five orders of magnitude compared to the unpurified calcite-rich carbonate samples. The precision and accuracy of this new method have been evaluated by measurements of the synthetic solution, carbonate standard material, and ten readily available Chinese carbonate reference materials. All the Mg isotopic analytical results were, within analytical uncertainties, essentially identical with the data published previously. Therefore, the new method can be a great option for purifying Mg from carbonate samples for isotopic analysis.

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Lu and Hf content, and Hf isotopic composition of 13 Chinese rock reference materials are reported for the first time. The reference materials span a broad compositional range. Results indicate that they are of comparable quality to the well characterised and widely utilised USGS and GSJ rock reference materials.

Absolute isotopic ratios are required for isobaric interference corrections, spike calibrations, and isotopic analysis by external normalization methods. However, high-precision natural isotopic abundance data are lacking for many elements, particularly those with less than four isotopes or having isobaric isotopes with other elements. In this study, we developed a method for absolute isotope ratio analysis, which integrates the concept of the double-spike method with isotopic analysis of element pairs that have isobaric isotopes. Using multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS), the isotopic composition of a sample can be derived by measuring a series of mixtures of the sample and a spike element that has an isobaric isotope with the element being analyzed. We applied this method to five pairs of elements (Ca-Ti, V-Ti, Cr-Ti, Ni-Zn, and In-Sn) and obtained the absolute isotopic ratios for Ca, V, Cr, Ni, and In, as well as the relative Ca isotopic composition. By simultaneous measurement of Ti and Ca isotopes, a quantitative relationship between the instrumental mass fractionation factors and element masses was developed. After correcting for the difference in instrumental mass fractionation factors, the obtained absolute ratios agree well with the literature data and have per mil level accuracy. This method has considerable potential in measuring the absolute isotopic ratios of elements that have isobaric isotope with other elements. Such precisely determined absolute isotopic ratios and the relationship between the instrumental mass fractionation factors and elemental masses will improve isobaric interference corrections, particularly when chemical purification is imperfect or during laser ablation analysis.

Online normalisation to isotope ratio of admixed internal standards is an important technique in isotopic analysis by multicollector ICP-MS (MC-ICP-MS). It is widely used for minimising drift in measurements of δ-values and calibrating isotope amount ratios for medium and heavy mass elements. However, its potential has been underexplored for light elements, largely due to the greater magnitude of instrumental isotope fractionation (IIF) observed in the low mass region and the need to conduct measurements in dynamic mode. This work reports for the first time a comprehensive assessment of the performance of Li, C, and Mg as internal standards for both relative and absolute 11B/10B isotope ratio measurements by MC-ICP-MS. The data show that normalisation to any of the tested elements allowed correcting for drift in IIF and obtaining more reproducible results. The regression model has been used to determine n(11B)/n(10B) isotope ratios in the NIST SRM 951a boric acid isotopic material with a certified boron isotope amount ratio. The n(11B)/n(10B) values and expanded uncertainties (k = 2) determined for this material by using isotopically certified Li, C, and Mg internal standards were 4.0688(569), 4.0439(264) and 4.0294(706), respectively, and agree well with the NIST SRM 951a certified value of 4.0437(033). Carbon has shown the best internal standard performance in the measurement of both δ11B and n(11B)/n(10B) values. Calibration of n(11B)/n(10B) isotope ratios using internal standards with SI-traceable isotope ratios offers a low-cost alternative method for establishing traceability of results to the SI. The ease of implementation of the method makes it a useful tool for fostering quality control procedures in laboratories seeking the ISO/IEC 17025:2017 accreditation.

Isotopic reference materials (IRMs) are crucial for securing accurate and precise isotope ratio measurements of non-traditional stable isotopic systems and for enabling comparison of isotope ratio data obtained at different labs. Fe and Mg isotopic analysis have gained considerable interest as it expands our understanding of critical geological and biological processes. However, the isotopic reference materials used for Fe (IRMM-014) and Mg (DSM3) isotopic analysis are either out of stock or not readily available. In this work, we report on the use of multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) for determination of the isotopic composition of the two new isotopic reference materials IRMM-524A and ERM-AE143, which can be used for high-precision isotopic analysis of Fe and Mg, respectively, instead of IRMM-014 and DSM3. The Fe isotopic composition of IRMM-524A, determined as the intercept of the best-fitting straight line (linear regression) through the data points for multiple reference materials of geological and biological origin, measured relative to both the conventional and new isotopic reference materials is δ56FeIRMM-014 = −0.004 ± 0.014‰ (2SD) and δ57FeIRMM-014 = +0.005 ± 0.024‰ (2SD), and thus, within the experimental uncertainty it is the same as the value for IRMM-014. Using the same regression method, ERM-AE143 is shown to be isotopically lighter than DSM3, with δ26MgDSM3 = −3.295 ± 0.040‰ (2SD), and δ25MgDSM3 = −1.666 ± 0.043‰ (2SD). These new reference materials can be recommended as secondary isotopic standards or as a replacement for the conventional or primary reference materials when these become exhausted. Additionally, we provide a comprehensive set of Fe and Mg isotopic compositions for 21 geological and 10 biological reference materials, as a contribution to the field of isotope geochemistry, as well as to the blooming field of isotope ratio applications in biomedicine.

Emerging applications in isotope geochemistry using stable metal isotope systems, including those in archaeological, environmental and medical sciences, along with commercial/industrial applications such as environmental source tracing and ore exploration, require high sample throughput that conventional element purification techniques—i.e. gravity flow ion exchange chromatography (IEC)—cannot match. Here, a simple and robust method for element purification from biological and geological samples has been developed, SpinChem™, wherein element purification via IEC is greatly facilitated through centrifugation. In brief, this involves adapting chromatographic columns for encapsulation within large (50 mL) centrifuge tubes, and subsequent element purification at enhanced flow rates (1.2–1.5 mL min−1) generated by centrifugal force. As proof of concept, Zn IEC purification from biological and geological materials has been detailed, demonstrating the utility of this method across the sample spectrum, and validating high yields (97 ± 4%), high separation efficiency and low contamination levels (blanks ≤1 ng). SpinChem™ IEC in the centrifuge proceeds at rates up to an order of magnitude faster than in gravity flow protocols, with 8–10 samples processed through IEC in under 2 hours (vs. 4–10 hours in gravity flow), while maintaining high subsequent MC-ICP-MS analytical precision, with average errors of 0.06‰ (2σ) or better for δ66Zn. Benchmarking this technique using an element very sensitive to endogenous and exogenous contamination (e.g. inefficient separation and external contaminants, respectively)—Zn—exemplifies the utility and high performance of this technique, and its ready adaptation to other isotope systems of interest, including Ca, Fe, Cu, Sr/Nd, Mo and Sn.

Despite a considerable reduction in the amount of lead (Pb) in the environment as a result of control measures and policies, environmental Pb exposure remains a major public-health issue. Using Pb isotopes is a powerful tool for tracking metal pollution in the environment, especially in natural water where—even at low concentrations—it can have negative health effects. We developed a new method of combining a commercially available chelex 100-DGT passive sampler and MC-ICP-MS laser ablation for measuring Pb-isotope compositions in natural water. This combination offers several advantages: (1) the DGT device samples an isotopic composition of natural water integrated over time and pre-concentrates metals in situ. (2) Laser ablation allows a direct analysis of DGT without chemical preparation, reducing preparation time and the risk of contamination. We used a low fluence (3.06 J cm−2) for linear ablation of squares with 150 μm sides, achieving optimal sensitivity without burning the sample. A good compromise between pulse-repetition rate (Hz) and scan speed (μm s−1) is necessary for obtaining good sensitivity with similar intensity on both standard and sample, while maintaining a low background level. For an accurate analysis of the Pb-isotope composition of DGT by LA-ICP-MS a matrix-matched calibration is necessary, which was easily produced by immersing DGT in a standard solution. Finally, a water-flow experiment in a column demonstrated that it possible to analyse Pb-isotope compositions in water by DGT and MC-ICP-MS laser ablation with sufficient precision (0.09% for 207Pb/206Pb) for distinguishing various anthropogenic Pb sources in the environment. This method offers new perspectives for public policy development as it facilitates isotopic monitoring of natural water, better to combat Pb pollution.

Here we report a novel and simple chromatographic procedure, involving the use of a single column packed with AGMP-50 cation-exchange resin, for separating Fe from geological matrices. This procedure was found to be suitable for both routine samples and samples with high contents of Cu. In our experiment, high-field-strength elements (HFSEs) and Al were first eluted using 4 mL of a mixture of 0.2 M HCl and 0.3 M HF, and then Fe was collected by using 6 mL of a mixture of 0.2 M HCl and 0.5 M HF. The residual matrix elements, such as Na, Mg, K, Ca and other trace elements, could not be eluted by such a mixture of dilute HF–HCl solutions, which enabled us to remove matrix elements effectively and enabled a recovery of Fe of close to 100%. The robustness of this procedure was further evaluated by carrying out replicated analyses of a series of geological reference materials, including basic rocks, intermediate rock, acidic rock and Mn-nodules. All of the Fe isotopic analytical results were, within analytical uncertainties, essentially identical with the data published previously. Therefore, this method may be a great option for purifying Fe from geological samples for isotopic analysis.

This study presents a rapid and simple method of high precision Ba isotope measurement for barite using H2O extraction. The main challenge for analyzing the Ba isotope composition of barite is how to digest barite into solution for chemical purification. We used H2O as a dispersant to rapidly extract ∼20–75 μg Ba as barite micro-particles (invisible to the naked eye) into suspension, and then these micro-particles were quickly dissolved in 3 mol L−1 HCl. The precision and accuracy of this method were rigorously evaluated by two ways. Firstly, we analyzed four synthetic barites made by mixing different proportions of pure barite and matrix rocks (black shale, carbonatite, and clastic rock) with high Ba content and different δ138/134Ba. Despite the variable proportions of barite in the synthetic standards (10%, 25%, 40%, and 70%), the average measured δ138/134Ba is 0.33 ± 0.03‰ (2SD, n = 8), well consistent with that of a pure barite standard (GBW07812, 0.33 ± 0.05‰, 2SD, n = 36). Secondly, we repeatedly analyzed five barite standards (NBS127, GBW07811, GBW07812, GBW07814, and GBW07816). The Ba isotope compositions of these barites determined by the H2O extraction method are well consistent with those previously measured by the Na2CO3 exchange method. The long-term external precision of δ138/134Ba is better than 0.05‰ (2SD). Compared with the Na2CO3 exchange method, the H2O-extraction method significantly simplifies the digestion procedure and improves the efficiency of barite Ba isotope analysis.

Volcanic-hosted iron deposits of the eastern Awulale metallogenetic belt in Central Asia possess a reserve of over 1.2 billion tons of iron ores and constitute one of the most important basements for high-grade iron resources in China. Skarns are widespread in these deposits and closely associated with iron mineralization. The ages of these skarns are unclear, and their genesis remains debated, preventing further investigation into their metallogenic processes. We focused on garnets in nine ore-bearing skarns from three large-scale iron deposits (Chagangnuoer, Dunde, and Beizhan) in the eastern Awulale belt. U-Pb dating was conducted on these garnets using our in-house reference material, the Taochong garnet (TC-13, Pb-Pb isochron age: 126.2 ± 2.3 Ma, initial 207Pb/206Pb ratio: 0.845 ± 0.022). Laser-ablation–multicollector–inductively coupled plasma–mass spectrometry (LA-MC-ICP-MS) was employed in the garnet U-Pb dating, and high-precision U-Pb ages (0.3%–1.6%) were obtained, highlighting the advantages of LA-MC-ICP-MS in dating low-U minerals. The garnet U-Pb ages of the nine skarn samples fall into three groups, i.e., 329.0 ± 5.1–326 ± 3.3 Ma (two samples), 316.3 ± 2.9–311.2 ± 2.4 Ma (six samples), and 295.6 ± 1.0 Ma (one sample), implying three episodes of skarn alteration in the volcanic-hosted iron mineralization system. The first and second episodes of skarns formed as a result of contact metasomatism between coeval volcanic rocks and limestone, and they have economically important iron mineralization. The third was likely caused by a local postcollision granitic intrusion, but its metallogenic potential deserves further assessment.

The data presented in this work summarize the results of Eu isotope ratio of NIST3117a standard reagent collected between December 2017 and July 2020, which were used standard isotope ratio for calculating delta notation of Eu isotope ratio in the geological rocks [1,2]. The Eu isotope ratio of NIST3117a using MC-ICP-MS was measured by conventional standard-sample-bracketing (SSB) and combined standard-sample bracketing and internal normalization (C-SSBIN) for comparison. Sm was used as a spike element for normalization in determining Eu isotope ratio. The purpose of data collection was to check homogeneity and stability of Eu isotope ratio for NIST3117a Eu standard reagent for determining Eu isotope fractionation in the various kinds of geological materials. The data can be used as bench mark for Eu isotope standard reagent for determining the degree of Eu isotope fractionation in the geological materials.

The Fe isotope ratios can be a useful tracer of geochemistry, biogeochemistry, and the environmental redox state. In this study, we investigated the feasibility of Fe isotopic analysis in Fe-dominated minerals by 193 nm excimer ns laser ablation combined with Nu Plasma 1700 high resolution MC-ICP-MS without matrix-match calibration. Several important instrument parameters were investigated, such as the effect of the addition of nitrogen gas and water vapor, the effects of analytical parameters such as ablation mode, laser fluence, pulse repetition rate, spot size on Fe isotopic mass bias during analysis were investigated as well. The results showed that the effects of ablation mode, spot size, laser pulse repetition rate, and line scan speed can be neglected, while laser fluence and matrix effects had significant influence on the Fe isotopic mass bias at dry plasma condition. These problems can be minimized using consistent lower fluence (1.5‒3.5 J·cm-2), as well as the wet plasma conditions can significantly reduce the matrix effect in Fe isotopic analysis. Fortunately, with the water vapor and nitrogen gas addition after the ablation cell, an accurate and precise Fe isotope in pyrite, manganite, hematite, and chalcopyrite analysis by ns-LA-MC-ICP-MS can be achieved with non-matrix-matched calibration. The obtained accuracy and reproducibility of the in situ determinations of δ56FeIRMM-014 were both better than ± 0.10‰ (2 SD). This study indicated that there was a serious matrix effect in the Fe isotopic analysis of Fe-dominated minerals by ns- LA-MC-ICP-MS, and nitrogen gas mixed with water vapor-assisted ns- LA-MC-ICP-MS were an appealing option for the in situ Fe isotope analysis of Fe-dominated minerals with non-matrix-matched calibration.