Search

Rationale: Neodymium isotopes are a powerful geochemical tool that has widely been used in terrestrial and extraterrestrial studies. Modern multicollector inductively coupled plasma mass spectrometers (MC‐ICP‐MS) allow fast, accurate, and precise analysis of the radiogenic Nd isotope ratio 143Nd/144Nd. These analyses comprise relatively high instrumental mass bias that is typically corrected for using the stable 146Nd/144Nd of 0.7219 and an exponential law. The instrument is usually tuned to optimize the operating conditions for isotope analysis, but this tuning is a trade‐off primarily between signal intensity, stability, and accuracy. Alternative, more effective approaches for mass bias correction have been proposed that use 145Nd/142Nd as normalizing ratio. However, one drawback of using this ratio is that the efficient removal of Ce from Nd is required to minimize the effect of isobaric interference of 142Ce on 142Nd. Methods: Here, we analyzed international Nd and rock reference materials using a Thermo Scientific Neptune Plus MC‐ICP‐MS to evaluate the sensitivity of 145Nd/142Nd‐based mass bias correction to varying Ce/Nd and in comparison with the commonly used 146Nd/144Nd‐based correction. Results: Our results show that the corrected 143Nd/144Nd of Ce‐doped JNdi‐1 and Ce‐containing USGS BCR‐2, NOD‐A‐1, and NOD‐P‐1 reference materials are insensitive to Ce/Nd of up to ~1. Conclusions: The correction of instrumental mass bias with 145Nd/142Nd as a normalizing ratio yields, as previously suggested, improved trueness and precision of 143Nd/144Nd data in comparison with 146Nd/144Nd‐based corrections, even under high Ce/Nd of ~1. This allows improved optimization of signal intensity during instrument tuning, which is particularly useful for natural samples with low Nd content. [Correction added on 10 December 2024, after first online publication: The Results and Conclusions in Abstract has been corrected in this version.] [ABSTRACT FROM AUTHOR]

A fully automated dual-column purification procedure for Zn from biological samples, designed for subsequent Zn isotopic analysis, is presented that utilizes the prepFAST MC™ system (Elemental Scientific), DGA resin (TrisKem International), and TK201 resin (TrisKem International). The procedure developed enables the unattended processing of 20 samples per day and is characterized by low and reproduceable blanks (< 1.5 ng), no carry-over or memory effect, high reusability (> 50 times), high Zn yields 100.1% ± 5.3% (2 SD, N = 22), and strong robustness to matrix variations across biological samples (bone, liver, hair, blood). Additionally, Zn isotopic analysis using MC-ICP-MS showed no significant on-column fractionation. The measured δ66Zn/64ZnIRMM values for NIST SRM 1400 (0.67‰ ± 0.07‰, U, k = 2), NIST SRM 1486 (0.91‰ ± 0.06‰, U, k = 2), NIST SRM 1577c (− 0.45‰ ± 0.05‰, U, k = 2), ERM-DB001 (− 0.35‰ ± 0.05‰, U, k = 2), GBW09101 (− 0.32‰ ± 0.08‰, U, k = 2), and SeroNorm whole blood L-3 (-0.15 ‰ ± 0.05 ‰, U, k = 2) are consistent with published values. The procedure developed makes Zn, an analytically challenging isotope system, more accessible, feasible, and reliable for a broader range of users while enabling high sample throughput. [ABSTRACT FROM AUTHOR]

The Chatkal–Kurama region in the central Tien Shan is a superlarge porphyry–epithermal gold ore province. The paleovolcanic area hosts world-class Au, Ag, and base-metal deposits (Kalmakyr, Kochbulak, Kanimansur, etc.). Using the high-precision (±0.02%) MC-ICP-MS method of lead isotope analysis, we studied a collection of 63 ore samples (47 of them are galena) from 18 deposits, which represent all types of Au–Ag, Au–Ag–base metal, and Cu–Au–Mo deposits known in the region. The same method was applied to study 21 samples of igneous rocks from this region, for which lead isotope composition was determined in monomineralic feldspar separates. The Pb isotope ratios 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb from the ore deposits vary within narrow ranges: 17.9885–18.1598, 15.5897–15.6412, and 38.0385–38.2380, respectively. These variations in relative terms are 0.94, 0.33, and 0.52%, respectively, and are among the smallest among ore provinces around the world. An even higher (two to five times) degree of homogeneity is typical of the Pb isotopic composition at individual deposits in the region. The lead isotope composition of deposits and ore fields in the Chatkal–Kurama region does not depend on their mineralogical and geochemical features but is instead controlled by the geological settings of the deposits. The discovered close similarity between ore deposits and Late Paleozoic granitoids in Pb isotope composition provides evidence in support of the hypothesis that genetic connection of the large-scale Au, Ag, and base-metal is genetically related to magmatism, which developed in a subduction environment. An interesting fact is that the Pb isotope composition is identical at the Kalmakyr Cu–Au–Mo porphyry deposit and the neighboring Akturpak Au epithermal deposit, which provides evidence that metals for these deposits (which are different in composition and were formed under different P–T parameters) were derived from a common source. The isotope composition and its evolutionary model characteristics according to the Stacey–Kramers model indicate (in agreement with the data on Sr and Nd) that Pb of the rocks and deposits in the region is mid-crustal, typical of island-arc regions of the Andean type. The mantle component of the source of the regional ore-bearing magmas was the material of mantle lithosphere and oceanic crust that was partially melted in a subduction environment in the mantle wedge zone. The ratio Th/U = 3.86–3.99, which is higher than the average crustal value, indicates a significant contribution of Precambrian basement rocks of the Chatkal–Kurama terrane to the petrogenesis of the ore-bearing magmas. [ABSTRACT FROM AUTHOR]

In order to ensure the accuracy and precision of data during the analysis of vanadium isotopes, and facilitate the comparison of data among laboratories internationally, considering the shortage of inventory for the commonly used reference materials from the United States Geological Survey (USGS), seven reference materials (JA-1, JB-3, JB-1b, JGb-1, GBW07105, GBW07123, and GBW07454) with unreported vanadium isotope composition were selected from the Geological Survey of Japan (GSJ) and the Institute of Geophysical and Geochemical Exploration, Chinese Academy of Geological Sciences (IGGE) and their vanadium isotopes were measured using MC-ICP-MS. Among these reference materials, the gabbro reference material JGb-1 has the highest δ51V value of −1.05‰±0.08‰, and the andesite reference material JA-1 has the lowest δ51V (−0.34‰±0.06‰). The δ51V values of the other reference materials range from −0.72‰ to −0.81‰, all falling within the MORB range. The reporting of the vanadium isotopic composition of these reference materials in this article will enrich the database of vanadium isotopic research and contribute to the future study of vanadium isotopes in more fields. [ABSTRACT FROM AUTHOR]

Gallium isotope is a potential geochemical tool for understanding planetary processes, environmental pollution, and ore deposit formation. The reported Ga isotope compositions (δ71GaNIST994 values) of some international geological standards, such as BCR-2 and BHVO-2 basalts, exhibit inconsistencies between different laboratories. During mass spectrometry analysis, we found that δ71GaNIST994 values of geological standards with or without the correction of the interference of 138Ba2+ (mass/charge ratio = 69) on 69Ga show significant isotope offsets, and thus efficient separation of Ba and correcting the interference of 138Ba2+ are both crucial to obtain accurate δ71Ga values. By comparing δ71GaNIST994 values (relative to NIST SRM 994 Ga) of the same geostandards from different laboratories, we suggest that the isotopic heterogeneity from NIST SRM 994 Ga is one of the key reasons for the inconsistencies in δ71GaNIST994 values of BCR-2 and BHVO-2. To facilitate inter-laboratory comparisons, we measured the Ga isotopic compositions of 11 geological reference materials (including Pb-Zn ore, bauxite, igneous rocks, and loess) and two Ga solution standards (NIST SRM 3119a and Alfa Aesar). The δ71GaNIST994 and δ71GaIPGP values of these reference materials vary from 1.12 ‰ to 2.63 ‰ and − 0.13 ‰ to 1.38 ‰, respectively, and can be used to evaluate the precision and accuracy of Ga isotope data from different laboratories. [ABSTRACT FROM AUTHOR]

Secondary ion mass spectrometry (SIMS) is often used to determine the sulfur contents and isotope ratios of metallic alloys in meteorites or high‐pressure experimental samples. However, SIMS analyses involve calibration and the determination of instrumental mass fractionation in reference materials with a matrix composition similar to that of the unknown samples. To provide metallic reference materials adapted to S measurements via SIMS, we synthesised a series of twenty‐eight alloys comprising four FeNi(±Si) compositions (Fe95Ni5, Fe90Ni10, Fe80Ni20, and Fe80Ni15Si5) with S contents varying from 100 μg g−1 to 4 g/100g using the "melt spinning" method, which guarantees that the metal alloys are rapidly quenched at ~ 106 K s−1. Sulfur contents were determined at the Service d'Analyse des Roches et Minéraux at the CRPG and absolute δ34S values were determined by multi‐collector ICP‐MS (MC‐ICP‐MS, ThermoScientific Neptune) and isotope ratio mass spectrometry (Thermoscientific Delta V). A δ34S value of 16.01 ± 0.31‰ was consistently obtained using the MC‐ICP‐MS, which was indistinguishable of the δ34S value of the FeS starting material (15.95 ± 0.08‰). It suggests that S did not undergo isotopic fractionation during the melting process. Of fifteen samples containing ≤ 5000 μg g−1 S, SIMS measurements with 15‐μm‐diameter spots were repeatable to within 10% relative (1 standard deviation, 1s) for S contents and 2‰ for δ34S values. However, samples containing > 5000 μg g−1 S showed FeNi–FeS immiscibility, leading to minor dispersion of the S mass fractions and δ34S values. No matrix effect was observed for Fe‐Ni, Si, or S contents in terms of the calibration curves and instrumental mass fractionation. We ultimately recommend eight samples as reliable reference materials for S isotopic measurements by SIMS, which we can share worldwide with other laboratories. [ABSTRACT FROM AUTHOR]

Magnesium isotope ratios in carbonate rocks and minerals play an important role in tracing geological and biological processes. We report δ26MgDSM3 values for the first time in ten carbonate reference materials (GBW07865, GBW07114, GBW(E)070159, GBW07136, GBW07108, GBW03109a, GBW07120, GBW07214a, IAEA‐B‐7 and IAEA‐CO‐8) with calcium to magnesium mass ratios around 1300 g g−1 and ultra‐low Mg mass fractions of 295 μg g−1. A combination of AG MP‐50 (100–200 mesh) and AG 50W‐X12 (200–400 mesh) resins for the matrix extraction and multi‐collector inductively coupled plasma‐mass spectrometry (MC‐ICP‐MS) were used for the isotopic measurements. This measurement procedure is applicable to materials with high and low Mg mass fractions (e.g., carbonates, lunar highlands anorthosites, ice core). It was validated using various types of reference material. In‐house synthetic solutions with 1000 and 1300 g g−1 [Ca]/[Mg] mass ratios yielded δ26MgDSM3 values at 2s = ±0.05‰ (n = 62), ‐4.89‰ and ‐4.89‰, respectively, indistinguishable from those of the pure Mg solutions, at ‐4.91‰. δ26MgDSM3 values in well characterised carbonatite and carbonate reference materials (such as JDo‐1, COQ‐1, GBW07133, GBW07217a and GBW07129), with varying MgO and CaO mass fractions, were in agreement with literature values. [ABSTRACT FROM AUTHOR]

Calibrated isotope ratio measurements underpin numerous areas of scientific enquiry. Isotope measurement results rely on reference materials in order to correct instrumental isotopic fractionation, a bias induced by all mass spectrometers. The reference values assigned to these materials are typically obtained using gravimetric mixtures of separated isotopes but such experiments are costly and thus rarely cross‐examined. Here we advance the concept of linking measurements of various isotope systems to provide a cost‐effective way to assess the reliability of the values assigned to isotopic primary standards. Using MC‐ICP‐MS, we apply this workflow to examine the consistency of a couple of long‐standing isotopic primary standards of copper, nickel and zinc. Our measurement results of the reference materials that define the isotope ratios and consequently the atomic weights of zinc and nickel, Ar(Zn, IRMM‐3702) = 65.3604 ± 0.0023 (95% confidence interval) and Ar(Ni, NIST SRM 986) = 58.6979 ± 0.0010 (95% confidence interval), show zinc to be 15‐sigma lighter and nickel 16‐sigma heavier than their certified values. These discrepancies are suggestive of a wider reproducibility crisis surrounding isotopic standards and a further cross‐examination of isotope ratios associated with primary reference materials is likely to identify yet‐unrecognised biases for many other elements of the Periodic Table leading to improvements of the overall reliability of research conclusions that relies on them. [ABSTRACT FROM AUTHOR]

Copyright of World Nuclear Geoscience is the property of World Nuclear Geoscience Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tin isotope ratios of eight different geological reference materials were determined using Neptune and Neoma (Thermo Fisher, USA) multi‐collector‐inductively coupled plasma‐mass spectrometry (MC‐ICP‐MS) systems using the 117Sn‐122Sn double‐spike technique. Tin was purified by two‐stage ion‐exchange chromatography with a recovery of 85% ± 5%, with isobarically interfering matrix elements being reduced to negligible levels. Doping experiments indicated that the Neoma instrument was less affected by isobaric interferences than the Neptune instrument. The determined δ124/116SnSRM3161a values are consistent with published values, and the long‐term (> 6 months) intermediate precision was better than ±0.01‰ amu−1 for both instruments. The method allows the Sn isotope ratios of samples containing ~ 2 ng of Sn to be precisely determined with an Sn solution concentration of 1 ng g−1. [ABSTRACT FROM AUTHOR]

We report the δ142/140Ce values for thirty‐three widely available geological reference materials (RMs), including igneous rocks, metamorphic rocks, sediments and soils. The Ce isotope ratios of twenty‐two Chinese RMs are reported for the first time. After chemical purification using TODGA resin (50–100 μm, Eichrom, USA), Ce isotope measurements of these RMs were conducted by multi‐collector inductively coupled plasma‐mass spectrometry (MC‐ICP‐MS) with a combined standard‐sample bracketing (SSB) and Sm‐doping technique. The data quality of the Ce isotope results was assessed by repeated measurement of pure Ce reference solutions (NIST SRM 3110, JMC304, CDUT‐Ce) and well‐characterised geological RMs (BHVO‐2, BCR‐2, Nod‐A‐1, Nod‐P‐1, etc.). Our results are in excellent agreement with previously reported values within intermediate measurement precision (±0.04‰, 2s). The igneous rock and soil RMs showed limited variations in δ142/140Ce values, which ranged from ‐0.036 ± 0.018‰ to 0.062 ± 0.046‰ and ‐0.015 ± 0.015‰ to 0.029 ± 0.009‰, respectively. The river/marine sediments and Mn nodules displayed variable Ce isotope ratios ranging from ‐0.005 ± 0.018‰ to 0.141 ± 0.023‰, suggesting detectable Ce isotopic fractionation during low‐temperature processes. [ABSTRACT FROM AUTHOR]

A new method for the direct measurement of 237Np/238U ratio in irradiated UO2 pellets by multicollection inductively coupled plasma mass spectrometry (MC-ICP-MS) is proposed. It allows the determination of ratios down to 10 × 10–6 mol·mol−1 using ion counter and Faraday cup. This approach was validated by intercomparison with the usual two-step-method (Quadrupole ICP-MS for 237Np determination and isotope dilution mass spectrometry (IDMS) for 238U). For ratios between 10 × 10–6 and 100 × 10–6 mol·mol−1, expanded uncertainties (k = 2) varied from 2.75% to 0.81%, twice lower than the uncertainties determined by the usual method. [ABSTRACT FROM AUTHOR]

This paper is a pilot study using lead isotope analysis to source native copper in the Lake Superior Basin. Forty Pb isotope samples are sampled from native copper deposits across the Lake Superior Basin and analyzed via MC‐ICP‐MS at Indiana University's Metal Isotope Lab. The result of this analysis demonstrates that there is a significant overlap between Pb signatures of native copper sources within the Lake Superior Basin. As a result, lead isotope analysis is not recommended as an alternative for sourcing native copper within the Lake Superior Basin. [ABSTRACT FROM AUTHOR]

Abstract The half-life of the extinct radiolanthanide $$^{146}\text{Sm}$$ 146 Sm , important for both geochronological and astrophysical applications, was re-determined by a combination of mass spectrometry and $$\alpha$$ α -decay counting. Earlier studies provided only limited information on all potential factors that could influence the quantification of the half-life of $$^{146}\text{Sm}$$ 146 Sm . Thus, special attention was given here to a complete documentation of all experimental steps to provide information about any possible artifacts in the data analysis. The half-life of $$^{146}\text{Sm}$$ 146 Sm was derived to be 92.0 Ma ± 2.6 Ma, with an uncertainty coverage factor of $$\mathsf{\textit{k}\!=\!1}$$ k = 1 .

Chemical and lead isotope analyses aided by metallographic examination of copper axes found at the Late Neolithic settlement of Kietrz in southwestern Poland provide new evidence for the origin of copper and metal trade routes in the region. Our results indicate that metal used for the axes could be sourced from copper mines in modern Slovakia, Bulgaria and perhaps Serbia. The evidence from this study confirms that the Funnel Beaker people from Poland became parties to a metal trading network that connected much of continental Europe in the mid‐4th millennium bce and provides a better understanding of how these contacts provided the background for the technological and socio‐economic developments of the Baden era. [ABSTRACT FROM AUTHOR]

Sea-to-land transfer of irradiated uranium in soil samples was measured along a transect from the Cumbrian coast south of the Windscale Sellafield nuclear site in a NE direction across the Cumbrian coastal plain. Soluble uranium components were extracted by ion exchange chromatography and ratios 236U:238U and 235U:238U were measured using multi-collector ICP-MS. The method employed demonstrated the utility of 236U ratio measurements for the determination of irradiated uranium in environmental samples. The results produced for uranium were like those that have been reported for other fission product and nuclear fuel components that have been shown to be marine in origin. Measured 236U levels were highest close to the seashore and decreased rapidly as an exponential function of distance. The results indicated the absence of depleted uranium, such as might result from the deposition of aerosols generated by the testing of DU munitions at the nearby Eskmeals firing range in all but one sample. [ABSTRACT FROM AUTHOR]

Lithium (Li) and boron (B) isotopes are excellent tracers in geological processes. In order to study and eliminate the memory effects of lithium and boron element in isotopic measurements using MC-ICP-MS, different background rinsing protocols were designed with reference to previous research. The δ7Li and δ11B values of different types of reference materials were tested to evaluate the long-term reproducibility of the measurements using designated rinsing protocols for at least six months. The results show that using only 0.3% NaCl solution to clean the background for 60s can significantly reduce the lithium background signal and ensure the 7Li background signal is less than 5mV within 24h. The long-term external precision of δ7Li values for Alfa Li, an in-house standard, was 0.13‰ (2SD, n=73). Rinsing solutions, such as NAF and NH3·H2O could not significantly reduce the boron background of the instrument. However, the flexible blank subtracting method was used for precise determination of δ11B values. The long-term external precision of δ11B values for Alfa B was 0.19‰ (2SD, n=60). The average δ7Li and δ11B values of different types of reference materials were tested using these rinsing protocols, and the results were well consistent with reported data, supporting the applicability of the conclusions. The BRIEF REPORT is available for this paper at http://www.ykcs.ac.cn/en/article/doi/10.15898/j.ykcs.202310260167.

Abstract A technique is developed to quantify the ultra-trace 231Pa (35–3904 ag) concentration in seawater using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The method is a modification of the process developed by Shen et al. (Anal Chem 75(5):1075–1079, 2003. https://doi.org/10.1021/ac026247r ) and extends it to the application of very low levels of actinides, and the 35 ag 231Pa can be measured with a precision of 15%. The total process blank for the water column was 0.02 ag/g, while the values of the large and small particles were ~ 30 ag/g. The ionization efficiency (ions generated/atom loaded) varies from 0.7 to 2.4%. The measurement time is 2–5 min. The amount of 231Pa needed to produce 231Pa data with an uncertainty of ± 0.8–15% is 35–3904 ag (~ 0.9 × 105 to 10 × 106 atoms). Replicate measurements of known standards and seawater samples demonstrate that the analytical precision approximates that expected from counting statistics, and that based on detection limits of 52 ag, 55 ag, and 28 ag, protactinium can be detected in a minimum seawater sample size of ~ 2.6 L for small suspended particulate matter (> 0.8 μm and 51 μm), and ~ 56 mL for filtered (

On the anoxic Archean Earth, prior to the onset of oxidative weathering, electron acceptors were relatively scarce, perhaps limiting microbial productivity. An important metabolite may have been sulfate produced during the photolysis of volcanogenic SO2 gas. Multiple sulfur isotope data can be used to track this sulfur source, and indeed this record indicates SO2 photolysis dating back to at least 3.7 Ga, that is, as far back as proposed evidence of life on Earth. However, measurements of multiple sulfur isotopes in some key strata from that time can be challenging due to low sulfur concentrations. Some studies have overcome this challenge with NanoSIMS or optimized gas‐source mass spectrometry techniques, but those instruments are not readily accessible. Here, we applied an aqua regia leaching protocol to extract small amounts of sulfur from whole rocks for analyses of multiple sulfur isotopes by multi‐collector inductively coupled plasma mass spectrometry (MC‐ICP‐MS). Measurements of standards and replicates demonstrate good precision and accuracy. We applied this technique to meta‐sedimentary rocks with putative biosignatures from the Eoarchean Isua Supracrustal Belt (ISB, >3.7 Ga) and found positive ∆33S (1.40–1.80‰) in four meta‐turbidites and negative ∆33S (−0.80‰ and −0.66‰) in two meta‐carbonates. Two meta‐basalts do not display significant mass‐independent fractionation (MIF, −0.01‰ and 0.16‰). In situ Re–Os dating on a molybdenite vein hosted in the meta‐turbidites identifies an early ca. 3.7 Ga hydrothermal phase, and in situ Rb–Sr dating of micas in the meta‐carbonates suggests metamorphism affected the rocks at ca. 2.2 and 1.7 Ga. We discuss alteration mechanisms and conclude that there is most likely a primary MIF‐bearing phase in these meta‐sediments. Our new method is therefore a useful addition to the geochemical toolbox, and it confirms that organisms at that time, if present, may indeed have been fed by volcanic nutrients. [ABSTRACT FROM AUTHOR]

The multi‐collector inductively coupled plasma‐mass spectrometer is an instrument suited to measuring sulfur isotopes in all types of samples, from ice cores and river waters to carbonates and Archaean rocks. Its main advantage is the more convenient method of sample preparation, as sulfate does not need to be reduced but purified from the sample through ion exchange. This method allows the measurement of unbiased and precise δ34S values from samples as small as 10‐nmol with a typical intermediate precision of 0.15‰ (2s) at 95% confidence. So far, no attempt has been made to understand at which levels of analytical precision and bias MC‐ICP‐MS could provide ∆33S values. Here, the first standard addition experiment undertaken for ∆33S evaluation shows that measurement results on a Neptune Plus MC‐ICP‐MS allows us to calculate ∆33S values identical to those established by other measurement principles, for samples down to 30 nmol S, with an intermediate precision as good as 0.05‰ (2s). Though this precision is not as good as the analytical precision of data acquired by the SF6 method, the advantages of small sample size and straightforward sample handling make it a very useful tool for investigating past and modern aspects of the sulfur cycle. [ABSTRACT FROM AUTHOR]

The stable Zr isotope ratios in zircon yield a novel geochemical tracer that, together with the Lu‐Hf and U‐Pb radiogenic isotope systems, allows for a better understanding of the magmatic evolution of silicate melts. We present a solution‐based procedure for coupled stable Zr, Lu‐Hf and U‐Pb isotope ratio determinations for individual zircons using a 91Zr‐96Zr tracer purified from Hf and a late‐spiking protocol for Zr. This method yields high‐precision Zr and Hf isotope results while maintaining low blank levels for U‐Pb isotope and Lu/Hf ratio determinations. With a two‐fold improvement on the precision relative to previous solution‐based work, we report δ94ZrIPGP‐Zr values (deviation of the 94Zr/90Zr ratio in the sample relative to the IPGP‐Zr reference material) and associated intermediate precisions (2s) for the zircon reference materials 91500, Mud Tank, Plešovice and Penglai of ‐0.041 ± 0.015‰, 0.018 ± 0.013‰, 0.089 ± 0.020‰ and ‐0.117 ± 0.021‰, respectively. Furthermore, this method yields un‐biased δ94ZrIPGP‐Zr and 176Hf/177Hf results for 25‐ng Zr and 0.56‐ng Hf aliquots of the Mud Tank zircon with intermediate precisions (2s) of 0.027‰ and 1.7 ε (parts per ten thousand), respectively. Thus, the presented method is applicable for the analysis of extremely small and rare zircon grains. [ABSTRACT FROM AUTHOR]

Solution MC‐ICP‐MS is an established technique for high precision boron isotope measurement results (δ11BSRM 951) in carbonates, yet its application to silicate rocks has been limited. Impediments include volatilisation during silicate dissolution and contamination during chemical purification. To address this, we present a low‐blank sample preparation procedure that couples hydrofluoric acid‐digestion and low‐temperature evaporation (mannitol‐free), to an established MC‐ICP‐MS measurement procedure following chemical purification using B‐specific Amberlite IRA 743 resin. We obtain accurate δ11BSRM 951 values (intermediate precision ±0.2‰) for boric acid (BAM ERM‐AE121 19.65 ± 0.14‰) and carbonate (NIST RM 8301 (Coral) 24.24 ± 0.11‰) reference materials. For silicate reference materials covering mafic to felsic compositions we obtain δ11BSRM 951 with intermediate precision < ±0.6‰ (2s), namely JB‐2 6.9 ± 0.4‰; IAEA‐B‐5 ‐6.0 ± 0.6‰; IAEA‐B‐6 ‐3.9 ± 0.5‰ (2s). Furthermore, splits of these same reference materials were processed by an alternative fusion and purification procedure. We find excellent agreement between δ11BSRM 951 measurement results by MC‐ICP‐MS of the reference materials using both sample processing techniques. These measurement results show that our sample processing and MC‐ICP‐MS methods provide consistent δ11BSRM 951 values for low B‐mass fraction samples. We present new data from Mid Ocean Ridge Basalt (MORB) glass, documenting a range in δ11BSRM 951 from ‐5.6 ± 0.3‰ to ‐8.8 ± 0.5‰ (2s), implying some upper mantle δ11BSRM 951 heterogeneity. [ABSTRACT FROM AUTHOR]

Uranium (U) associated with coal can be an important source of U and result in environmental pollution during coal combustion. In this study, we developed a method for measurement of U isotope ratios in coals using multiple‐collector inductively coupled plasma‐mass spectrometry. The 233U‐236U double‐spike was utilised to calibrate the instrumental isotopic fractionation. High‐pressure bomb and dry ashing were adopted to digest the coal samples. The δ238UCRM‐145 values obtained from the two different digestion procedures were in good agreement. The δ238UCRM‐145 of seven coal and one fly ash reference materials are reported. Furthermore, the results of fly ash, bottom ash and feed coal samples reveal that the combustion processes lead to relatively small U isotopic fractionation between the samples within the same coal‐fired power plant, indicating that U isotope data can be used as a tracer for heavy metal pollution resulting from coal combustion. The U isotope measurement method of coal established in this study provides technical support to understand the behaviour of U during coal formation and combustion. [ABSTRACT FROM AUTHOR]

Copyright of Rock & Mineral Analysis is the property of Editorial Board of Rock & Mineral Analysis and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

High concentrations of toxic cadmium (Cd) in soils are problematic as the element accumulates in food crops such as rice and cacao. A mitigation strategy to minimise Cd accumulation is to enhance the competitive uptake of plant-essential metals. Theobroma cacao seedlings were grown hydroponically with added Cd. Eight different treatments were used, which included/excluded hydroponic or foliar zinc (Zn) and/or iron (Fe) for the final growth period. Analyses of Cd concentrations and natural stable isotope compositions by multiple collector ICP-MS were conducted. Cadmium uptake and translocation decreased when Fe was removed from the hydroponic solutions, while the application of foliar Zn-EDTA may enhance Cd translocation. No significant differences in isotope fractionation during uptake were found between treatments. Data from all treatments fit a single Cd isotope fractionation model associated with sequestration (seq) of isotopically light Cd in roots and unidirectional mobilisation (mob) of isotopically heavier Cd to the leaves (ε114Cdseq-mob = −0.13‰). This result is in excellent agreement with data from an investigation of 19 genetically diverse cacao clones. The different Cd dynamics exhibited by the clones and seen in response to different Fe availability may be linked to similar physiological processes, such as the regulation of specific transporter proteins. [ABSTRACT FROM AUTHOR]

Tungsten (W) isotopes are useful tools in geological and cosmochemical research, but the chemical separation of W is cumbersome for high‐precision measurement. Here, a novel alkali (sodium hydroxide, NaOH) precipitation method for separation and purification of W in geological samples is described, which simplifies the chemical procedure. The amphoteric character of W is exploited to separate it from most matrix elements in alkaline conditions. Subsequently, TEVA resin was applied to further purify W for measurements using a multi‐collector inductively coupled plasma‐mass spectrometer. Importantly, the introduction of a certain amount of Na in the W analyte can increase the signal intensity by approximately 1.6 times, which may be caused by Coulomb fission. Such Na‐triggered signal enhancement reduces the test portion mass required for analysis. Our results show that the Alfa Aesar W standard solution and geological reference materials JB‐3, BCR‐2 and BHVO‐2 yield 182W/184W ratios consistent with previously reported values within uncertainty. Repeated measurement of the Alfa Aesar W standard solution shows that the intermediate precision of 182W/184W was better than 5 ppm (2s), which is sufficient to identify subtle 182W isotope variations in terrestrial and extra‐terrestrial samples. Above all, the alkali precipitation method in this study optimises the experimental process and mass spectrometric analysis. [ABSTRACT FROM AUTHOR]

An interlaboratory comparison (ILC) was organised to characterise 87Sr/86Sr isotope ratios in geological and industrial reference materials by applying the so‐called conventional method for determining 87Sr/86Sr isotope ratios. Four cements (VDZ 100a, VDZ 200a, VDZ 300a, IAG OPC‐1), one limestone (IAG CGL ML‐3) and one slate (IAG OU‐6) reference materials were selected, covering a wide range of naturally occurring Sr isotopic signatures. Thirteen laboratories received aliquots of these six reference materials together with a detailed technical protocol. The consensus values for the six reference materials and their associated measurement uncertainties were obtained by applying a Gaussian, linear mixed effects model fitted to all the measurement results. By combining the consensus values and their uncertainties with an uncertainty contribution for potential heterogeneity, reference values ranging from 0.708134 mol mol‐1 to 0.729778 mol mol‐1 were obtained with relative expanded uncertainties of ≤ 0.007 %. This study represents an ILC on conventional 87Sr/86Sr isotope ratios, within which metrological principles were considered and the compatibility of measurement results obtained by MC‐ICP‐MS and by MC‐TIMS is demonstrated. The materials characterised in this study can be used as reference materials for validation and quality control purposes and to estimate measurement uncertainties in conventional 87Sr/86Sr isotope ratio measurement. [ABSTRACT FROM AUTHOR]

Uranium isotope ratios are reported for twenty‐nine geological reference materials (RMs) including igneous, metamorphic and sedimentary rocks, as well as sediments. Measurements were conducted on a multi‐collector inductively coupled plasma‐mass spectrometer (MC‐ICP‐MS) using the 233U‐236U double spike technique. These RMs possess a wide range of matrices with U mass fractions ranging from 0.11 μg g‐1 to 18.7 μg g‐1. The δ234/238U values (relative to the n(234U)/n(238U) ratio at secular equilibrium) show minor fluctuations around the secular equilibrium value except for two Pleistocene speleothem RMs. The δ238/235U values (relative to the value for NBL CRM 112a (NBS SRM 960)) of igneous rocks and metamorphic rocks are within the range of the continental crust value (‐0.29 ± 0.03‰, 95% CI). The δ238/235U value for sedimentary rock and sediment RMs spans a wide range of 0.98‰, suggesting significant 238U/235U isotopic fractionation in low temperature environments. The range of δ238/235U RMs reported in this study (‐0.63‰ to 0.35‰) exceeds that of previous RMs (‐0.61‰ to 0.17‰), allowing inter‐laboratory calibration of wider ranges of geological and environmental samples. [ABSTRACT FROM AUTHOR]

Here we present an analytical method for Zinc (Zn) isotopic measurements using "standard‐sample bracketing" on a Nu Sapphire multi‐collector inductively coupled plasma‐mass spectrometer. The effects of Zn mass fraction and HNO3 molarity mismatch between the standard and the sample, as well as the presence of matrix elements have been evaluated. Long‐term reproducibility of better than ±0.03‰ for δ66Zn (2s) was routinely obtained. Accurate measurements were achieved when CNi/CZn < 0.001, CTi/CZn < 0.03, CBa/CZn < 0.05, CNa/CZn and CAl/CZn < 0.5, CMg/CZn < 0.1, CFe/CZn < 5 and CCu/CZn as well as CCd/CZn < 10. High‐precision Zn isotopic determination were performed on twenty‐one widely available geological certified reference materials, with an overall range of ~ 0.62‰ (0.15 to 1.07‰), which is nearly twenty times the current analytical precision (0.03), and the results are in agreement with most previously published data within 2s. Among them, δ66ZnJMC 3‐0749L of eleven geological certified reference materials are reported for the first time: 0.22 ± 0.03‰ (dolerite, DR‐N), 0.23 ± 0.02‰ (gabbro, GSR‐10), 0.20 ± 0.04‰ (microgabbro, PM‐S), 0.15 ± 0.02‰ (andesite, GSR‐2), 0.22 ± 0.08‰ (diorite, GSR‐9), 0.19 ± 0.07‰ (syenite, GSR‐7), 0.30 ± 0.06‰ (granite, GSR‐1), 0.25 ± 0.00‰ (rhyolite, GSR‐11), 0.37 ± 0.01‰ (shale, GSR‐5), 0.21 ± 0.03‰ (limestone, GSR‐6) and 0.20 ± 0.03‰ (hornblendite, GSR‐15). The novel Zn isotopic data from these certified reference materials can be used for future interlaboratory comparisons. [ABSTRACT FROM AUTHOR]

A technique is developed to quantify the ultra-trace 231Pa (35–3904 ag) concentration in seawater using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The method is a modification of the process developed by Shen et al. (Anal Chem 75(5):1075–1079, 2003. https://doi.org/10.1021/ac026247r) and extends it to the application of very low levels of actinides, and the 35 ag 231Pa can be measured with a precision of 15%. The total process blank for the water column was 0.02 ag/g, while the values of the large and small particles were ~ 30 ag/g. The ionization efficiency (ions generated/atom loaded) varies from 0.7 to 2.4%. The measurement time is 2–5 min. The amount of 231Pa needed to produce 231Pa data with an uncertainty of ± 0.8–15% is 35–3904 ag (~ 0.9 × 105 to 10 × 106 atoms). Replicate measurements of known standards and seawater samples demonstrate that the analytical precision approximates that expected from counting statistics, and that based on detection limits of 52 ag, 55 ag, and 28 ag, protactinium can be detected in a minimum seawater sample size of ~ 2.6 L for small suspended particulate matter (> 0.8 μm and < 51 μm), ~ 3.0 L for large suspended particulate matter (> 51 μm), and ~ 56 mL for filtered (< 0.45 μm) seawater. The concentration of 231Pa (several attograms per liter) can be determined with an uncertainty of ± 2–8% (2σ) for suspended particulate matter filtered from ~ 60 L of seawater. For the dissolved fraction, ~ 1 L of seawater yields 231Pa measurements with a precision of 0.8–10%. The sample size requirements are several orders of magnitude less than traditional decay-counting techniques, and the precision is better than that previously reported for ICP-MS techniques. Our technique can also be applied to other environmental samples, including river, lake, and cave water samples. [ABSTRACT FROM AUTHOR]

Hypomagnesemia was historically prevalent in individuals with type 1 diabetes mellitus (T1DM), but contemporary results indicate an incidence comparable to that in the general population, likely due to improved treatment in recent decades, resulting in better glycemic control. However, a recent study found a significant difference between the serum Mg isotopic composition of T1DM individuals and controls, indicating that disruptions to Mg homeostasis persist. Significant deviations were also found in samples taken one year apart. To investigate whether the temporal variability in serum Mg isotopic composition is linked to the transient impact of administered insulin, Mg isotope ratios were determined in serum from 15 T1DM individuals before and one hour after insulin injection/meal consumption using multi-collector inductively coupled plasma-mass spectrometry. Consistent with results of the previous study, significant difference in the serum Mg isotopic composition was found between T1DM individuals and 10 sex-matched controls. However, the average difference between pre- and post-insulin injection/meal T1DM samples of 0.05 ± 0.13‰ (1SD) was not significant. No difference was observed for controls before (−0.12 ± 0.16‰) and after the meal (−0.10 ± 0.13‰) either, suggesting a lack of a postprandial Mg isotopic response within one hour of food consumption, and that the timing of the most recent meal may not require controlling for when determining serum Mg isotopic composition. [ABSTRACT FROM AUTHOR]

Zinc, an essential trace element that serves as a cofactor for numerous cellular and viral proteins, plays a central role in the dynamics of HIV-1 infection. Among the viral proteins, the nucleocapsid NCp7, which contains two zinc finger motifs, is abundantly present viral particles and plays a crucial role in coating HIV-1 genomic RNA, thus concentrating zinc within virions. In this study, we investigated whether HIV-1 virus production impacts cellular zinc homeostasis and whether isotopic fractionation occurs between the growth medium, the producing cells, and the viral particles. We found that HIV-1 captures a significant proportion of cellular zinc in the neo-produced particles. Furthermore, as cells grow, they accumulate lighter zinc isotopes from the medium, resulting in a concentration of heavier isotopes in the media, and the viruses exhibit a similar isotopic fractionation to the producing cells. Moreover, we generated HIV-1 particles in HEK293T cells enriched with each of the five zinc isotopes to assess the potential effects on the structure and infectivity of the viruses. As no strong difference was observed between the HIV-1 particles produced in the various conditions, we have demonstrated that enriched isotopes can be accurately used in future studies to trace the fate of zinc in cells infected by HIV-1 particles. Comprehending the mechanisms underlying zinc absorption by HIV-1 viral particles offers the potential to provide insights for developing future treatments aimed at addressing this specific facet of the virus's life cycle. [ABSTRACT FROM AUTHOR]

This study identified the provenance of Pb flux used in the production of the glaze of unique, high‐quality late medieval stove tiles from the northern part of the Carpathian Basin, and elaborated and evaluated a fast preparation process to measure Pb isotope ratios in high‐Pb glazes. We compared three different methods of preparation. Method 1 consisted of the dissolution of bulk chips of glaze, dilution of the solution and mass spectrometric analysis without Pb purification. Method 2 collected the Pb from the surface of the glaze with acid‐impregnated swabs, subsequent dilution and direct analysis of the sample solution. Method 3 used solutions from method 1, extraction of Pb by ion‐exchange chromatography and analysis of the purified Pb. Each preparation method produced a similar Pb isotope ratio. The majority of the Pb isotope ratios fall into one group and indicate that lead imported from the Krakow–Silesia mining region was mainly used for production of the glazes of the stove tiles made by different workshops. [ABSTRACT FROM AUTHOR]

Boron (B) is a light and fluid-mobile element. It has two stable isotopes: 10B and 11B. The two isotopes fractionate significantly in nature due their relatively large mass difference. Therefore, B isotopes are one of the non-traditional stable isotope tracers, which have been used in the research areas of chemistry, environmental, bioscience, earth and planetary sciences. In the last twenty years, the analytical methods of B isotopes have been continuously improved and many important advances have been made. However, there are still some challenges to obtaining high-quality B isotope data. The techniques of B isotope analysis are quite different among laboratories, which arise principally from three stages: sample digestion, purification, mass spectrometry.Because B is volatile and isotopic fractionation may be induced by different coordination in different pH environments, sample digestion, and purification have a great impact on the high-precision measurement of B isotopes. Four digestion methods have been applied for extracting B from samples, including pyro-hydrolysis, acid dissolution, alkali fusion, and ashing. Pyro-hydrolysis requiring large volumes of water is time-consuming. Acid dissolution is one of the most popular techniques due to the small volumes of reagents needed and hence lower levels of contamination. Samples are dissolved with different acids such as hydrochloric, nitric, hydrofluoric, and perchloric. Painstaking attention is required with hydrofluoric acid since BF3 is highly volatile and easily lost in nature. Suitable amounts of mannitol are added during acid dissolution to form a stable boron-mannitol complex to prevent the loss of B and avoid B isotope fractionation.Alternatively, alkali fusion is a dissolution method for solid rock samples. High purity fluxing agent is needed, such as K2CO3, Na2CO3, NaOH, NaOH, and Na2O2. As all the B would be present as borate in the resulting alkaline solution, alkali fusion eliminates the risk of B isotope fractionation due to evaporation. The advantage of this method is that it is rapid and relatively large numbers of samples can be processed. The ashing is mainly used to digest plant samples. Ashing was chosen for plant sample decomposition because ashing removes the organics and avoids the use of reagents carrying a B blank or generating isobaric interferences.Once a sample is dissolved, it is necessary to purify B before analysis. There are two principal methods currently in use, which are ion exchange and microsublimation. The ion exchange techniques can be divided into those involved in using B-specific resin Amberlite IRA 743 and those using cation (AG50W-X8/AG50W-X12) or anion (Bio-Rad AG MP-1) cation exchange resins. Microsublimation is an effective and simple method to purify B. It is used to purify B from organic-enriched solutions. Microsublimation appears advantageous in terms of matrix removal efficiency and low procedural blank, however the technical challenges involved are also great.There are two main types of B isotope analytical methods: in-situ and solution methods. Solution methods analyse B ratios using thermal ionization mass spectrometry (TIMS) method or multiple collector inductively coupled plasma-mass spectrometry (MC-ICP-MS). The in-situ method, uses secondary ion mass spectrometry (SIMS) method or laser ablation multiple collector inductively coupled plasma-mass spectrometry (LA-MC-ICP-MS) to measure samples with high B concentration. The accurate and precise determination of the B isotope composition is still a difficult task. For solution methods, the difficulty arises principally from the near ubiquitous level of B contamination in most standard clean laboratories, the light mass of the element, the occurrence of only two stable isotopes, and the large mass difference between them. For in-situ approaches, the difficulty arises principally from a lack of reference materials, surface contamination, limited precision in low-concentration samples, and limitations in reproducibility in high-concentration samples. On the whole, MC-ICP-MS is the dominant method for B isotopic analysis, which is still has the challenges of matrix effect, memory effect, and mass bias.The relevant techniques inherent to the three stages of B isotope analysis are summarized and the advantages and disadvantages of the different techniques are discussed. The aim of the work contained in this paper is to further promote the progress and development of domestic and foreign scholars in the research of B isotope geochemistry.

In this study we determined rubidium isotope ratios in twenty‐one commonly used international geological reference materials, including igneous, sedimentary and metamorphic rocks, as well as an IAPSO seawater reference material. All δ87Rb results were obtained relative to the NIST SRM 984 reference material. For most reference materials, Rb was purified using a single column loaded with Sr‐spec resin. For reference materials containing low Rb but high mass fractions of matrix elements (such as basic rock and seawater), Rb was purified using two‐column chromatography, with the first column packed with AGMP‐50 resin and the second column packed with Sr‐spec resin. Two methods for instrumental mass bias correction, sample‐standard bracketing (SSB) mode, and the combined sample‐standard bracketing and Zr internal normalisation (C‐SSBIN) method, were compared for Rb isotopic measurements by multi‐collector inductively coupled plasma‐mass spectrometry (MC‐ICP‐MS). The long‐term reproducibility of Rb isotopic measurements using both methods was similar, better than 0.06‰ (2s, standard deviation) for NIST SRM 984. Significant Rb isotopic fractionation was observed among the reference materials, with an overall variation in δ87Rb values of approximately 0.5‰. The δ87Rb values of igneous rocks ranged from ‐0.28‰ to +0.06‰, showing a trend from heavier isotopic compositions in mafic rocks to lighter δ87Rb values in the more evolved felsic rocks. The sedimentary and metamorphic rocks had Rb isotope ratios similar to those of igneous rocks. The δ87Rb values of the reference materials related to low‐temperature geological processes showed a wider range than those of high‐temperature processes. Notably, the IAPSO seawater reference material had a δ87Rb value of +0.14‰, which deviated from that of igneous rocks, and represents the heaviest reservoir of Rb isotopes found thus far on Earth. The comprehensive dataset presented here has the potential to serve for quality assurance purposes, and provide a framework for interlaboratory comparisons of Rb isotope ratios. [ABSTRACT FROM AUTHOR]

This paper describes the isotopic and quantitative analysis of single micrometer-sized uranium particles by multiple mass spectrometric techniques combined with a micromanipulating technique. Secondary ion mass spectrometry performed the best for the isotopic analysis of single uranium particles in terms of accuracy and precision compared to scanning electron microscope (SEM)/thermal ionization mass spectrometry and SEM/multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS). A single uranium particle was dissolved in high-purity acid and quantitated by MC-ICP-MS and isotope dilution MS. The resulting uranium mass per particle was close to the reference value. [ABSTRACT FROM AUTHOR]

Indium (In) behaves as a moderately volatile metal during nebular and planetary processes, and its volatility depends strongly on oxygen fugacity. The In isotopic composition of the bulk silicate Earth (BSE) could provide a critical constraint on the nature of Earth's building blocks and mechanisms that lead to its volatile depletion. However, accurately and precisely determining the isotopic composition of In of the silicate Earth is challenging due to its low abundance in igneous rocks and the presence of significant isobaric interferences on its isotopes (e.g., 113Cd+ on 113In+ and 115Sn+ on 115In+). Here, we present a purification procedure for In from rock matrices and report the first dataset of In isotopic compositions of 30 terrestrial igneous rocks, one biotite geostandard, and one carbonaceous chondrite (Allende) measured on a Nu Sapphire collision-cell equipped multi-collector inductively-coupled-plasma mass-spectrometer (CC-MC-ICP-MS) with an external reproducibility of 0.11‰ (2SD). At this level of precision, we find no statistically significant difference in the In isotopic compositions of mid-ocean-ridge basalts (MORB), oceanic island basalts (OIB), and continental flood basalts (CFB). Furthermore, Canary Islands, Iceland and Afar lavas display no analytically resolvable In isotopic variations from basalts to rhyolites. Therefore, In isotope fractionation during igneous processes is smaller than our analytical uncertainty and the In isotopic compositions of basalts are likely to be representative samples of their mantle sources. The twenty-one terrestrial basalts from diverse geological settings have an average δ115In of 0.35 ± 0.07 ‰ (2SD). This value represents the current best estimate of the In isotopic composition of the mantle as well as of the bulk silicate Earth, assuming limited In isotope fractionation during mantle partial melting, and due to the small contribution of the continental crust to the In budget (<5%). This isotopic composition provides a baseline with which to compare with chondrites and differentiated planetary bodies in future studies. [ABSTRACT FROM AUTHOR]

BACKGROUND: Marine sedimentary carbonate rock is an important carrier for recording seawater information. The Sr isotope composition (87Sr/86Sr) of carbonate rocks can reflect the relative contribution of the continental crust and mantle to the Sr isotope composition of seawater. The long-term variation trend of Sr isotope composition in geological history can be used to interpret global tectonic events, weathering rate changes, biogeochemical cycles, and determine the age of marine sedimentary strata. However, the carbonate rocks likely contain non-carbonate fractions to varying degrees, which lead to the whole rock Sr isotope composition being unequal to that of the primary carbonate fraction. In order to obtain the primary carbonate fraction that reflects the primitive seawater, an effective leaching method is required. OBJECTIVES: To identify experimental procedures and target leaching steps that can effectively extract representative primary carbonate fractions in carbonate rock samples of varying purity and variety. METHODS: Reference materials of dolostone and limestone (GBW03105a and ECRM-782-1) were selected to represent carbonate rock samples with high purity, and natural samples of limestone (C-3, purity: 85%) and dolostone (E-3, purity: 65%) were selected to represent samples with low purity. The leaching solution of all steps was measured for Ca and Mg contents by inductively coupled plasma-optical emission spectrometry (ICP-OES), for Sr, Mn and Al contents by inductively coupled plasma-mass spectrometry (ICP-MS). The Sr isotope was measured by multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) after purification of the leaching solution. Through the utilization of various indicators, such as Sr/Ca and Mn/Sr, the targeted leaching steps were ascertained. RESULTS: (1) Factors affecting the Sr isotope composition of the primary carbonate fraction. The detection of Sr isotope composition of primary carbonate fraction is affected by the soluble and exchangeable Sr, resulting in higher 87Sr/86Sr values. Thus, the pre-leaching step is essential for the multiple-step leaching method. It is shown that an excess of 5% acetic acid can cause leaching of non-carbonate fraction of limestone and affect the Sr isotope composition of the primary carbonate fraction. (2) Comparison and selection of multiple-step extraction methods. (a) It is recommended to use the method proposed by Li, et al[29] for limestone samples. It was found that the carbonate of GBW03105a and C-3 dissolved in the target steps (A10-A11) proposed by Liu, et al[13] accounted for 46.51% and 39.49% of the total carbonate fraction. A large number of target carbonate was dissolved rapidly in these two steps without considerable differentiation. In the method proposed by Li, et al[29], GBW03105a and C-3 target steps (B7-B9) dissolved carbonate accounted for 26.41% and 30.31% of the total carbonate fraction. The target steps are close to the step of non-carbonate fractions dissolved in strong acid. For natural samples with complex mineral compositions, the method proposed by Li, et al[29] may have leached non-carbonate fractions, which resulted in a higher 87Sr/86Sr value for testing. Therefore, the more conservative method proposed by Li, et al[29] is recommended for leaching unknown limestone samples, and B7-B9 are the target steps for leaching representative primary carbonate fraction. (b) The method proposed by Liu, et al[13] is recommended for dolostone samples. Liu, et al[13] selected acetic acid with different concentration ranging from 0.25%-10% for leaching. The carbonate fraction is almost completely dissolved, and the lowest Sr isotope value measured is lower than the method proposed by Li, et al[29] . Hence, to choose the concentration of acetic acid from low to high for leaching is helpful to separate the target fractions of dolostone samples. The same concentration of acetic acid is chosen by the method of Li, et al[29], and the dissolution rate of samples with different purity began to slow down at A9, leaving about 30% of the carbonate fraction not leached. Thus, it is difficult to judge whether the target carbonate fraction using this method has been leached completely. For the multiple-step leaching of unknown dolostone samples, the method proposed by Liu, et al[13] is recommended here, and A14-A15 are selected as the target steps for leaching representative primary carbonate fraction. (3) Optimization of a multiple step leaching method. The insoluble powder in the leaching solution will be digested by the subsequent addition of nitric acid, which can affect the Sr isotope value of the target fraction. This study has found that the Al/Ca ratio in the acetic acid leaching part is lower than that in Li, et al[13] (Fig.3b), indicating that the filter can reduce pollution caused by the dissolution of non-target fractions. In addition, the preleaching steps can also be optimized. The experimental data showed that 5mL of 1mol/L ammonium acetate could be selected for pre-leaching to simplify the experimental procedure and shorten the processing time. CONCLUSIONS: Based on prior research, a focused multiple-step leaching method for carbonate rocks is proposed. Limestone samples (purity≥85%) are suitable for 9-step leaching with 1% acetic acid, and the target steps are L7-L9; dolomite samples (purity≥65%) are suitable for the 14-step leaching method with 0.25%-10% acetic acid, and the target steps are D13-D14. The Sr isotope value of the primary carbonate fraction of the European Committee for Steel Standardization (ECISS) dolostone reference material ECRM-782-1 has been reported for the first time, which is 0.707868±0.000034 (n=12, 2SD). In the future, the experimental methods will be further improved to encompass samples from diverse sources and varying purity, thereby ensuring the reliability and universality of the experimental approach. [ABSTRACT FROM AUTHOR]

BACKGROUND With mining activities taking place on a global scale, the concern for environmental issues within and around mines continues to increase. The advent of multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) has promoted the geochemical study of isotopes and has led to the widespread use of isotope tracing techniques to investigate various issues in the mining environment. OBJECTIVES To systematically summarize the various types of studies currently conducted on the application of isotope tracing technology in mining environments, with the aim of highlighting the importance of the application of isotope tracing technology in complex mining environments and the diversity of scientific problems it can solve. METHODS Data published by scholars at home and abroad by July 2022 has been collected and compiled on testing and analyzing the supply source/connection of mine water body, sulfate/carbonate source and the cause of acid mine wastewater (AMD), migration and transformation of mining elements, different sources and contribution rates of heavy metal pollution with the help of isotope tracer technology. The study area covers more than 40 regions in 20 countries. RESULTS It is found that hydrogen and oxygen isotope tracing techniques in water bodies are effective tools for mine water source analysis, hydraulic linkage studies and AMD source identification. Sulfate sulfur and oxygen isotope tracing techniques provide important support for the study of sulfate sources in mine environments, AMD acidification processes and pollution, bacterial sulfate reduction and elemental migration transformation. Heavy metal isotope (Pb, Cd, Zn, Hg isotopes) tracing technology is an effective way to investigate the sources of metal pollution in mines and nearby environments and the contribution of different sources. CONCLUSIONS Although isotope techniques play an important role in resolving the sources of environmental pollutants in mines and the mechanisms of migration and transformation of characteristic pollutants and revealing the hydrogeochemical processes in mines, most of the current studies are limited to the application of single/few isotopes for short time tracing studies of environmental media in mines. Therefore, further development of multi-isotope tracing technology is needed in the future, as well as long-term and continuous monitoring and investigation of various problems in the mine environment. New and effective methods for pollution prevention and control are also proposed.

Simple Summary: Alzheimer's disease is the most prevalent form of dementia and is associated with multiple alterations in biological processes. The most profound changes consist of the formation of two types of protein aggregations, called β-amyloid plaques and neurofibrillary tangles of tau proteins. Different biologically relevant metals are believed to play a role during the development of Alzheimer's disease, including copper. In Alzheimer's disease, copper has been reported to interact with β-amyloid plaques and neurofibrillary tangles, while in addition its homeostasis and metabolism are known to be affected. Therefore, Cu was investigated in a murine model mimicking Alzheimer's disease. These mice were genetically manipulated, resulting in the presence of typical Alzheimer's disease symptoms. By making use of two inductively coupled plasma-mass spectrometry (ICP-MS) based analysis techniques, the Cu concentration and the ratio between the natural 65Cu and 63Cu isotopes (65Cu/63Cu) were determined in blood plasma and four different brain regions—brain stem, cerebellum, cortex, and hippocampus—of young and aged Alzheimer's mice and age-matched healthy controls. The Cu concentration in blood plasma was significantly altered in response to both age- and Alzheimer's-related effects, whereas the blood plasma Cu isotope ratio was affected in the Alzheimer's-affected mice only. Both the brain stem and cerebellum showed changes in Cu concentration and 65Cu/63Cu isotope ratio as a result of ageing and the development of Alzheimer's disease. Finally, a correlation was observed between the 65Cu/63Cu isotope ratio in the cerebellum and blood plasma. Determination of Cu concentration and isotope ratio is therefore a relevant tool to unravel the role of Cu in ageing and Alzheimer's disease. Alzheimer's' disease (AD) is characterized by the formation of β-amyloid (Aβ) plaques and neurofibrillary tangles of tau protein in the brain. Aβ plaques are formed by the cleavage of the β-amyloid precursor protein (APP). In addition to protein aggregations, the metabolism of the essential mineral element Cu is also altered during the pathogenesis of AD. The concentration and the natural isotopic composition of Cu were investigated in blood plasma and multiple brain regions (brain stem, cerebellum, cortex, and hippocampus) of young (3–4 weeks) and aged (27–30 weeks) APPNL-G-F knock-in mice and wild-type controls to assess potential alterations associated with ageing and AD. Tandem inductively coupled plasma-mass spectrometry (ICP-MS/MS) was used for elemental analysis and multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) for high-precision isotopic analysis. The blood plasma Cu concentration was significantly altered in response to both age- and AD-related effects, whereas the blood plasma Cu isotope ratio was only affected by the development of AD. Changes in the Cu isotopic signature of the cerebellum were significantly correlated with the changes observed in blood plasma. The brain stem showed a significant increase in Cu concentration for both young and aged AD transgenic mice compared with healthy controls, whereas the Cu isotopic signature became lighter as a result of age-related changes. In this work, ICP-MS/MS and MC-ICP-MS provided relevant and complementary information on the potential role of Cu in ageing and AD. [ABSTRACT FROM AUTHOR]

In terms of isotopic technologies, it is essential to be able to produce materials with an enriched isotopic abundance (i.e., a compound isotopic labelled with 2H, 13C, 6Li, 18O or 37Cl), which is one that differs from natural abundance. The isotopic-labelled compounds can be used to study different natural processes (like compounds labelled with 2H, 13C, or 18O), or they can be used to produce other isotopes as in the case of 6Li, which can be used to produce 3H, or to produce LiH that acts like a protection shield against fast neutrons. At the same time, 7Li isotope can be used as a pH controller in nuclear reactors. The COLEX process, which is currently the only technology available to produce 6Li at industrial scale, has environmental drawbacks due to generation of Hg waste and vapours. Therefore, there is a need for new eco-friendly technologies for separation of 6Li. The separation factor of 6Li/7Li with chemical extraction methods in two liquid phases using crown ethers is comparable to that of COLEX method, but has the disadvantages of low distribution coefficient of Li and the loss of crown ethers during the extraction. Electrochemical separation of lithium isotopes through the difference in migration rates between 6Li and 7Li is one of the green and promising alternatives for the separation of lithium isotopes, but this methodology requires complicated experimental setup and optimisation. Displacement chromatography methods like ion exchange in different experimental configurations have been also applied to enrich 6Li with promising results. Besides separation methods, there is also a need for development of new analysis methods (ICP-MS, MC-ICP-MS, TIMS) for reliable determination of Li isotope ratios upon enrichment. Considering all the above-mentioned facts, this paper will try to emphasize the current trends in separation techniques of lithium isotopes by exposing all the chemical separation and spectrometric analysis methods, and highlighting their advantages and disadvantages. [ABSTRACT FROM AUTHOR]

Lithium (Li) isotopes have been widely used to investigate continental weathering, climate change, recycling of surface materials and ore formation. However, muti-column systems and/or a large volume of eluents are generally required for Li purification and its accurate isotopic measurements due to variably high matrix/Li ratios of different geological materials. Here we present a simplified dual-column system with small volumes of resins (3 mL + 2 mL) and eluents (16 mL 0.5 M HCl + 22 mL 0.2 M HCl) for Li purification of various geological materials. This system can efficiently separate Li from matrix elements with a very low blank level (∼25 pg), high yield (99.3%–99.8 %) and narrow Li collection ranges (10 mL in each column stage). Additionally, we first demonstrate that the largest total cation content of loaded samples can be up to 24.4 % of the resin (AG 50W-X8) capacity for Li purification. The effects of acid and Li concentration mismatch, solution Li concentration and matrix elements on the accuracy and precision of Li isotopic analysis are also systematically evaluated for the new generation of dual-path MC-ICP-MS (Nu Sapphire). The reliability of the new procedure for Li purification and isotopic analysis is confirmed by analyzing twelve international geological reference materials (including ten mafic to felsic silicate igneous rocks, a meta-sediment (SDC-1) and a carbonatite (COQ-1)) and results obtained are consistent with previously reported data with a long-term reproducibility better than 0.20 ‰ (2SD). Therefore, our study provides a simplified and efficient system for Li purification and isotopic analysis by MC-ICP-MS. [Display omitted] • First quantificational evaluation of the loading capacity of the AG 50W-X8 resin. • A simplified and efficient dual-column system is developed for Li purification. • Evaluation of acid/Li concentration mismatch, Li concentration and matrix effects. • The reliability of this method confirmed by twelve geological reference materials. [ABSTRACT FROM AUTHOR]

BACKGROUND Soil cadmium pollution has become one of the main factors that endanger human health. Rapid and effective remediation of Cd pollution soil requires a fundamental understanding of Cd sources and geochemical cycling. With the advancement of Cd isotope analysis technology and the in-depth understanding of its fractionation mechanism, Cd isotopes provide new perspectives for understanding the source and fate of Cd in the soil. OBJECTIVES To systematically summarize the cadmium isotope analysis method, and emphasize the research progress, problems, and potential application of Cd isotopes as tracers in soil. METHODS Sample digestion methods, such as high-temperature digestion bombs, microwave acid digestion, ashing, and acid extraction, are reviewed here with ion-exchange separation and multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS). RESULTS Based on previous studies, this review systematically summarizes the fundamental principle and methodology of Cd isotopic analysis methods. For the soil samples, the high-temperature digestion bombs method and microwave acid digestion can meet its cadmium isotope analysis requirements. With sufficient recovery and complete removal of interfering elements, standard-sample bracketing, external normalization, and double-spike techniques can be used for mass bias correction to obtain accurate and reliable Cd isotope data. In addition, the theoretical basis of soil cadmium isotope tracing was reviewed. This review summarizes the cadmium isotopic composition of multiple potential cadmium sources in soil and the direction and extent of cadmium isotope fractionation in typical processes (weathering leaching, adsorption, precipitation/co-precipitation, complexation). Combined with the latest research results, the application of cadmium isotopes in tracing soil cadmium sources and their migration and transformation processes is summarized. CONCLUSIONS In the future, we should further develop and optimize the high-precision cadmium isotope analysis method, construct the fingerprint map of soil cadmium isotope, and reveal the cadmium isotope fractionation mechanisms in the processes of multi-component and multi-interface.

This study presents high‐precision W isotopic measurement results using the 180W‐183W double spike technique with MC‐ICP‐MS. The effects of isobaric and polyatomic interferences on W isotopic measurements were evaluated. The δ186/184W values were not significantly affected when the solution had Hf/W ≤ 3 × 10‐4, Ta/W ≤ 1, Os/W ≤ 0.06, Ce/W ≤ 0.0075, Nd/W ≤ 3.5 and Sm/W ≤ 5. The intermediate measurement precisions of both standard solutions (NIST SRM 3163 and Alfa Aesar W) and geological reference materials (NOD‐A‐1) were better than ±0.024‰ (2s). We also obtained a precision of 0.026‰ for a minimum sample loading mass of 5 ng, allowing the analysis of samples with low W contents. Replicated measurements of geological reference materials (AGV‐2, BCR‐2, BHVO‐2, GSP‐2, RGM‐1, SDC‐1, NOD‐A‐1 and NOD‐P‐1) yielded δ186/184W values ranging from 0.017‰ to 0.144‰. The δ186/184W values of two major tungsten ore minerals (scheelite and wolframite) were reported and compared herein. Scheelites had systematically slightly heavier W isotopic compositions than wolframites, which may reflect differences in the crystal structure. The resolvable variations of stable/mass‐dependent W isotopic compositions in rocks and ore minerals make W isotopes a novel tool for studying hydrothermal mineralisation processes and the W cycle of geological reservoirs. [ABSTRACT FROM AUTHOR]