Multi-collector Inductively Coupled Plasma Mass Spectrometer Research Articles

The isotopic composition of the new enriched silicon crystal Si28-31Pr11: maintaining the realization and dissemination of the mole and the kilogram via the XRCD method

The molar mass and isotopic composition of a new silicon single crystal material (Si28-31Pr11) highly enriched in 28Si has been determined in the context of the x-ray crystal density method used for the realization and dissemination of the SI base units‒the mole and the kilogram. Isotope ratio measurements have been performed using a high-resolution multicollector-inductively coupled plasma mass spectrometer (MC-ICP-MS) with improved technical performance. By applying the Virtual-Element Isotope Dilution Mass Spectrometry method, different crystal areas enclosing the locations of two silicon spheres have been investigated with respect to the magnitude of tentative variations in the molar mass and isotopic composition of the respective samples as a function of their original location in the crystal ingot. In total, 18 subsamples from four different axial and several related radial positions have been characterized. An average molar mass M(Si28-31Pr11) = 27.976 941 464(41) g mol−1 corresponding to a relative combined uncertainty u c,rel(M(Si28-31Pr11)) = 1.4 × 10−9 was yielded. The average enrichment in 28Si of the crystal is expressed by the mean amount-of-substance fraction x(28Si) = 0.999 985 350(37). Two spheres were cut from the crystal ingot. The average molar masses of the spheres Si28kg_03_a and Si28kg_03_b are: M(Si28kg_03_a) = 27.976 941 467(43) g mol−1 and M(Si28kg_03_b) = 27.976 941 461(44) g mol−1, respectively. The results are discussed using uncertainty budgets according to the Guide to the expression of uncertainty in measurement. A homogeneous distribution of the molar mass throughout the crystal is suggested, qualifying it as a material for a primary standard–a silicon sphere–for the realization and dissemination of the mole and the kilogram. A comparison with enriched silicon crystals that are already available is given.

New Pb isotopic data from Japanese hydrothermal deposits for tracing heavy metal sources

Lead isotopes are useful in determining the source of metals in environment, and studies on lead isotopic characteristics of mineral deposits have provided important insights for economic geologists, archaeologists and environmental scientists over the past 50 years. This study reports new Pb isotope and trace element data of sulfide minerals from 25 mineral deposits in Japan in order to partly update the data set reported in the 1980s, which have long been used for provenance studies. The analytical precision of the Pb isotope ratios, measured by multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS) in this study, is an order of magnitude higher than the previous data set, allowing regional- and deposit-level discrimination of isotopic signatures. The Pb isotope ratios of vein-type or intrusion-centered Japanese deposits from this study (206Pb/204Pb = 18.151–18.545, 207Pb/204Pb = 15.552–15.642, 208Pb/204Pb = 38.389–38.918) are mostly within the range of data from Japanese deposits of the same type measured in previous studies but tend to have slightly lower 207Pb/204Pb and 208Pb/204Pb ratios. This is likely be due to the differences in analytical instrumentation and isotopic variations within the deposit, which should carefully be considered in future regional-scale provenance studies. Data from the Sai, Ohizumi, Budo and Shiraita deposits in Northeast Japan as well as the Kishu and Tokoo deposits in Southwest Japan indicate a two-component mixing presumably involving magma and meteoric fluid. The isotopic variation within each of these deposit is much smaller compared to previously reported variations within volcanogenic massive sulfide deposits in Japan, indicating a relatively uniform metal source with only a small contribution from basement rocks. In contrast, Daira and Ani deposits in Northeast Japan have highly variable isotopic characteristics similar to volcanic rocks with lower crustal assimilation, indicating an additional input of material from the lower crust.

A New Sample Processing Protocol for Separation and Purification Enabling Precise Analysis of Various Non-Traditional Isotopes in Geological Samples with Low Concentrations

Many non-traditional isotopes, such as chlorine, magnesium, calcium, etc., are widely used as groundwater tracers. A new sample processing protocol of purification and concentration for isotopic analysis is presented to overcome many of the major drawbacks of existing methods. Contemporary sample preparation often requires several laborious off-line procedures in a ultra clean laboratory prior to instrumental determination; additionally, interference ions in real samples are difficult to completely remove, especially when the concentration of those ions is equal to that of the target ions. The new protocol includes the following steps: (i) one-step purification using a newly developed isotopic preparative chromatograph (IPC) with a background suppressed mode to obtain extremely pure components that only have target ions and H2O; (ii) enrichment of the collected pure solution from the previous step using a newly developed ultra clean concentrator filled with high purity nitrogen; (iii) transforming the enriched target ion into suitable speciation inside the ultra clean concentrator; (iv) finally, sending the enriched solutions to a multi-collector inductively coupled-plasma mass-spectrometer (MC-ICP-MS) or thermal ionization mass spectrometer (TIMS). The present method was validated using certified reference materials and real samples for both chlorine and magnesium; the precision of chlorine ratio value was generally below 0.22‰ and that of Mg was below 0.12‰. This processing protocol provides a potential method for isotope sample preparation and analysis in a small number of geological samples with low concentrations of many other elements or compounds such as nitrate, sulfate, lithium, calcium, strontium, etc.

High-precision zinc isotope measurement of chemically different geostandards by multicollector inductively coupled plasma mass spectrometry.

Zinc isotopes are becoming increasingly applicable in high-temperature geochemistry, for example in crust-mantle interaction and volatilization-related processes. The published zinc isotope data for some commonly used reference materials, however, show large interlaboratory offsets. In addition, there is still limited data for zinc isotope compositions of many widely used geological reference materials. For precise and accurate zinc isotopic ratio analysis of chemically diverse geostandards, including ultramafic to felsic igneous rocks, carbonatites, sediments and soils, an improved procedure for chemical purification of zinc was introduced in this study. The factors potentially affecting zinc isotopic ratio measurement were assessed. The accuracy and long-term reproducibility were obtained by measurements on both synthetic solutions and well-characterized geostandards. Purification of geologic samples with different zinc concentrations and matrix compositions yields consistent elution curves with nearly 100% recovery. Acidity and concentration mismatches and the presence of some matrix elements (e.g., Mg, Ti and Cr) have significant impacts on the precision and accuracy of zinc isotopic ratio measurement. The zinc isotope compositions of a suite of reference materials were measured using this method. The present study describes methods for the chemical purification of zinc and high-precision and accurate zinc isotopic ratio measurements using multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS). The long-term external reproducibility for δ66 Zn values is ±0.04‰ (2SD). High-quality zinc isotope data of chemically different geostandards were reported to stimulate future interlaboratory calibrations.

#3539 CALCIUM ISOTOPE RATIOS IN SERUM ARE THE STRONGEST PREDICTOR OF BONE CALCIUM BALANCE IN PATIENTS ON DIALYSIS

Abstract Background and Aims Dysregulated mineral homeostasis is common in chronic kidney disease (CKD) and associated with bone demineralization and vascular calcification. The balance between bone formation and resorption, which reflect the bone calcium (Ca) balance (BCaB), cannot be determined without bone biopsy which is invasive and not easily repeatable. Recently, we have shown that stable (i.e. non-radioactive) Ca isotopes, 42Ca and 44Ca, can be measured in serum and their ratio (δ44/42Caserum) quantitatively determines net bone gain or loss of Ca. Thus, when bone formation exceeds bone resorption, the net BCaB is positive and δ44/42Caserum is high, and when bone resorption is the predominant process δ44/42Caserum is low compared to age-matched controls. In this study we compared δ44/42Caserum against δ44/42Cabone and arterial biopsy samples (δ44/42Caartery) and the sensitivity of δ44/42Ca in predicting changes in bone histology. Method Adults receiving chronic dialysis who underwent bone and arterial biopsies at the time of kidney transplantation were recruited. Patients who had parathyroidectomy or received cinacalcet or anti-resorptive agents were excluded. All participants had Dual Energy X-ray Absorptiometry (DXA) of the hip and lumbar spine. Ca44 and Ca42 measurements were performed in serum and bone and arterial biopsy samples using a multi-collector inductively-coupled plasma mass spectrometer (Thermo Fisher Scientific, Germany). Results Nineteen patients, median age 59.8 years, 84% male, median time on dialysis 3.3 years were included. δ44/42Ca was significantly higher in serum compared to bone or arterial biopsy samples (p < 0.0001), with the lowest isotope ratios in bone (Fig. 1A). δ44/42Cabone was significantly lighter than δ44/42Caartery (p = 0.0002; Fig. 1B). δ44/42Cabone correlated positively with the osteoblastic markers BAP and P1NP (p = 0.0006, R2 = 0.51 and p = 0.009, R2 = 0.31) and inversely with PTH and the osteoclastic marker RANKL (p = 0.0017, R2 = 52 and p = 0.02, R2 = 0.29 respectively; Fig. 2). Both the DXA hip and lumbar spine T-scores and z-scores correlated positively with δ44/42Cabone. δ44/42Caserum showed an inverse correlation with the osteoid area (p = 0.04, R2 = 0.22) and a positive correlation with the absolute mineralized area and the trabecular thickness (p = 0.0004, R2 = 0.58 and p = 0.013, R2 = 0.34 respectively. The were no significant correlations with δ44/42Caartery. On multivariable linear regression analysis significant predictors of δ44/42Caserum were δ44/42Cabone (p = 0.018, 95%CI −1.35 to −0.16), age (p = 0.02, 95%CI 0.002 to 0.02) and BAP (p = 0.019, 95%CI 0.04 to 0.38), together predicting 71% of the variability in δ44/42Caserum. The only significant predictor of δ44/42Cabone was the δ44/42Caserum: p = 0.004, 95%CI −1.6 to −0.37, model R2 = 69%. Conclusion δ44/42Caserum is a significant and independent maker of BCaB, correlating with bone histology measures, and may provide a more sensitive measure than DXA or bone biomarkers. Further studies are required to determine the clinical utility of using δ44/42Caserum to guide management of mineral bone disease in CKD.

Uranium Isotope Ratios of Twenty‐nine Geological Rock Reference Materials Measured by MC‐ICP‐MS

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.

Simultaneous U and Th isotope measurements for U-series dating using MCICPMS

U-series dating is a well-established tool for determining the ages of secondary carbonates in palaeoclimate science.We present a measurement method and data treatment protocol adapted for simultaneous Th and U isotope measurements with sub-‰ precision by using a combination of Faraday cups and a secondary electron multiplier on a multi-collector inductively coupled plasma mass spectrometer (MCICPMS). We systematically analyse the effect of undetected variations in raw data corrections on the accuracy of the activity ratios and ages using three representative speleothem and coral samples.On masses of 229 and 230 amu, we observe “ghost signals” for which we introduce appropriate correction factors. Not accounting for the “ghost signal” can lead to deviations from reference values of more than 10% for young materials. Other data corrections induce accuracy variability on ε-to ‰-levels. The resulting methodology permits measurements on the ε-level for (234U/238U) and on the (sub) permille-scale for (230Th/238U) determinations.

Triple silicon isotope insights into the formation of Precambrian cherts

Cherts are pervasive in the Precambrian and their O and Si isotopic compositions have been used extensively for reconstructing seawater paleo-temperatures. However, these reconstructions are obscured by the fact that cherts exhibit, at a given age, a large isotopic (O and Si) heterogeneity at bulk and micrometer scales. This is understood as reflecting the fact that cherts are an assemblage of silica precursors having different origins, and that diagenesis and metamorphism have modified the isotopic compositions acquired during the last equilibration with seawater. To test the contributions of the different processes that control the Si isotopic composition of cherts, we developed high-precision triple Si isotope measurements by Multicollector-Inductively Coupled-Plasma Mass-Spectrometer (MC-ICP-MS). This approach allows to identify deviations from the equilibrium Si isotopic fractionation at the level of a few ppm. Triple Si isotope data combined with trace elements and O isotope data in Precambrian cherts demonstrate that three different sources of silica were involved in the formation of cherts, and that both equilibrium and kinetic isotopic fractionation took place for Si. Archean seawater is predicted to have a triple Si isotopic composition kinetically fractionated relative to bulk silicate Earth. This requires a large kinetic isotopic fractionation during hydrothermalism of the oceanic crust and appears consistent with warm oceans in the Precambrian. However more work is required on the triple isotope systematics of Si inputs and output to seawater by rivers and authigenic clays formation. Triple Si isotope variations can thus be used as a new tool to unravel the origin of cherts and of their O and Si isotopic compositions. The present evidence of kinetic isotopic fractionations for Si isotopes also implies that Si isotopes should be associated to triple O isotope for paleotemperature reconstructions.

Development of an analytical method for accurate and precise determination of rare earth element concentrations in geological materials using an MC-ICP-MS and group separation.

The concentration of rare earth elements (REEs) in geological materials including SLRS-6 (natural water certified reference material) and JB1b, JA1, and JG2 (Standard Rock Materials of Geological Survey of Japan) can be used as a tracer to characterize various geochemical processes in earth systems. Particularly, accurate and precise determination of rare earth element concentration in natural waters is difficult due to their extremely low concentration and the interference of polyatomic oxides. In this study, we developed a method for accurate and precise determination of the REE (particularly heavy rare earth elements) concentrations in geological materials including natural waters using a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS) and group separation by 2-hydroxyisobutyric acid (HIBA). The REEs were separated into light rare earth elements (LREEs, La-Ce-Pr-Nd), middle rare earth elements (MREEs, Sm-Eu-Gd-Tb), and heavy rare earth elements (HREEs, Dy-Ho-Er-Tm-Yb-Lu) by a cation-exchange column (AG50W-X8 200-400 mesh) using HIBA. The recovery rates of each REE in the natural water sample exceeded 98%, whereas the recovery rates of each REE in rock materials exceeded 95% except for HREEs. The method developed in this study can accurately measure the REE concentrations (particularly HREE) in geological materials without polyatomic oxide interference during the REE analysis by using the MC-ICP-MS and, thus, can correctly interpret the geochemical implications of REEs in geological systems. The determination of the Sr concentrations and Sr isotopic ratios of SLRS-6 CRM and JB1b, JA1, and JG2 SRMs is also reported, and they are shown to be in good agreement with the recommended values.

Heavy metals, rare earth elements and isotopic fingerprint of Venetian Protected Designation of Origin sparkling wines

PurposeWorld imports of Italian sparkling wines fell by 9% in value and 5% in quantities. In view of this, the quality characterisation of these products is desirable to increase their market value and restore their global visibility.Design/methodology/approachFor this purpose, in this paper, heavy metals (Cd, Co, Cr, Cu, Fe, Ga, Hf, Hg, Mn, Mo, Nb, Ni, Pb, Re, Sb, Sn, Ta, Th, Tl, U, W, V, Zn, Zr), rare Earth elements (REEs) (Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Sm, Tb, Tm, Yb) and isotopes ratio (208Pb/206Pb, 207Pb/206Pb, 206Pb/204Pb, 208Pb/207Pb, 87Sr/86Sr) were analysed in Italian sparkling wines with Protected Designation of Origin (PDO) certification by High Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS) and MultiCollector Inductively Coupled Plasma Mass Spectrometer (MC-ICP-MS). The samples were produced in the Veneto region, and they were compared to white and red wines from the same area.FindingsSparkling wines present a characteristic elemental pattern compared to white and red ones, with lower content of heavy metals and higher content in REEs. The ratio 87Sr/86Sr resulted in a powerful micro-scale geographical origins marker while Pb ratios as winemaking process one, both useful to prevent possible frauds. Multivariate data analyses, such as PCA and PLS-DA, were used to develop a model of recognition of Venetian sparkling wines.Originality/valueThe good classification of sparkling wines was achieved (95%), proving the suitable use of these analytes as markers for recognising sparkling wines and their geographical origin verification. To the best of the authors’ knowledge, this is the first study investigating heavy metals, REEs and isotopes in Venetian sparkling wine for their recognition.

Calcium isotope measurements using a collision cell (CC)-MC-ICP-MS

Calcium is a major element in terrestrial planets and has six stable isotopes, including 40Ca which is a product of radioactive decay of 40K (T1/2 = 1.25 Gyrs). Calcium isotope geochemistry has therefore been used to trace biological and geological processes in various environments as well as radiogenic dating. However, it has been technically impossible to analyze stable and radiogenic isotopes simultaneously and high precision measurements usually require tens of micrograms of Ca. Here, we present high-precision Ca isotopic data, including the stable isotopes 42Ca, 43Ca and 44Ca as well as the radiogenic 40Ca using a Nu Sapphire multi-collector inductively-coupled-plasma mass-spectrometer (MC-ICP-MS), that is equipped with a collision cell to minimize Ar based interferences. The stable isotopic variations are reported using the delta notation (δ40/44Ca, δ42/44Ca, δ43/44Ca), which is the permil deviation of a given ratio from the NIST SRM 915b standard. The radiogenic excess is reported as ε40Ca, the per ten thousand deviation of the 40Ca/44Ca ratio from the same standard, after internal normalization to the 42Ca/44Ca ratio. We tested the influence of various parameters (Ca concentration, Ca and HNO3 concentration mismatch between sample and standard, effect of matrix elements) on the precision and accuracy of the measurements. We show that, using ~ 100 ng is sufficient to obtain high precision (<100 ppm, 2SD) δ40/44Ca and ε40Ca using a standard bracketing technique-this represents an improvement by over an order of magnitude in sensitivity compared to any previous methods. It should be noted that a limitation is that the intensities of the standard and sample must be matched very closely (better than 2%). Following this recommendation, the Ca isotopic compositions of 9 geological samples reported here is consistent with previous data. For example, the ε40Ca value of GSP-2 (3.92 ± 0.48 ‱) is within error with literature data (values between 3.69 and 4.32 ‱). Using this method, it is therefore possible, for the first time, to obtain simultaneously high-precision radiogenic and stable Ca isotopes on small samples, which will certainly open up many novel applications of Ca stable isotopes.

(U,Th)-He dating of Pleistocene carbonates: Analytical methods and age calculations

The uranium-thorium-helium ((U,Th)-He) dating method applied to calcium carbonate speleothems holds much promise for constraining the timeline of hominin evolution, as well as for palaeoclimatology research beyond the range of U/Th disequilibrium dating. Technical problems are posed by often low U concentrations and the requirement that samples need to be individually removed from the ultrahigh vacuum (UHV) system after helium is extracted from them, to be then analyzed for U, Th content and U series disequilibrium. We describe a low-cost furnace with this capability, constructed from standard UHV components, as well as the methods for subsequent U/Th disequilibrium analysis using multicollector ICP mass spectrometry. We present analytical and numerical solutions to determine (U,Th)-He ages for four conditions that have been encountered: (1) for an age range in which the residual activity ratio (234U/238U) can still be resolved but not that of (230Th/234U) (up to about 3000 ka), (2) for an age range where neither can be resolved (unlimited), (3) for ages up to 1000 ka where both activity ratios may be resolvable, and (4) for cases where (234U/238U) and (230Th/234U) indicate ages < 200 ka but (U,Th)-He systematics point to much older ages.•Helium extraction is carried out using an in-house built vacuum furnace that allows for large sample sizes (20 to 100 mg) of powdered carbonate material wrapped in Cu foil.•U and Th are separated together using Eichrom UTEVAⓇ resin and their isotope abundances are measured together in a single 2-cycle dynamic run using the multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS).•(U,Th)-He ages are calculated using four methods that take into account the U/Th disequilibria.

Rapid unseparated rare earth element analyses by isotope dilution multicollector inductively coupled plasma mass spectrometry (ID-MC-ICP-MS)

We present a method for analyzing rare earth elements (REEs) by isotope dilution without separation of individual elements. Utilizing a Nu Plasma 2 multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS) equipped with an Aridus II desolvation nebulizer, sample introduction tuning parameters (torch position, gas flows) were investigated and used to minimize oxide formation (e.g., NdO/Nd <0.05%) and obviate the need to analyze the REEs as separated “cuts.” Ratios for spike isotopes relative to reference in mixed elemental standards containing varying amounts of Ce, Nd, Sm, Eu, Gd, Dy, Er, and Yb were measured accurately within 1% of IUPAC values. La and Lu in the standards deviated more than 2% from expected values due to more pronounced interferences reducing the efficacy of corrections. A USGS (United States Geological Survey) BCR-2 rock standard was also processed with flux fusion, iron coprecipitation and bulk REE separation by a single column pass followed by analysis. The concentrations for Ce, Nd, Sm, Eu, Dy, Er, and Yb fell within 2% of consensus values. A USGS BIR-1A rock standard was also processed in triplicate by hydrofluoric and nitric acid digestion followed by iron coprecipitation and a single ion exchange column pass, yielding rare earth concentrations within 3% of consensus values with 0.3% relative standard deviation (n = 3). This demonstrates the ability to produce high quality REE patterns of comparable quality to traditional methods which require labor and time intensive REE separation, but with sample preparation and analytical times that are comparable to isotope dilution analyses by single-collector ICP-MS.

Certification of a Natural Silicon Reference Material with SI‐Traceable Isotopic Composition

Silicon (Si) is the second most abundant element in the continental crust. Studies have illustrated that silicon isotopes have a potential to be tracers in the biogeochemical silica cycle. This paper details a developed method for the production and certification of a new Si reference material with natural‐like isotopic composition using a fully calibrated multi‐collector inductively coupled plasma‐mass spectrometer (MC‐ICP‐MS). To correct for the mass bias effect, three blend solutions were gravimetrically prepared with isotopically enriched 28Si, 29Si and 30Si materials. Homogeneity and stability tests were performed, and no significant influences were found. Uncertainties of property values were evaluated, and the traceability to the International System of Units (SI) was established. The developed certified reference material (GBW04503) is a silicon powder (≈ 300 mesh) with high purity (≈ 0.999 99 kg kg−1), which can be used in silicon isotopic measurement to support validation of analytical procedures and/or quality control of gas source mass spectrometry (GS‐MS) or MC‐ICP‐MS. The certified isotope amount ratios of n(29Si)/n(28Si) and n(30Si)/n(28Si) are 0.050291(12) mol mol−1 and 0.033397(16) mol mol−1, respectively, (k = 2), and the certified isotope amount fractions of silicon are 92.2776(20)% (28Si), 4.6407(10) % (29Si) and 3.0818(14)% (30Si) (k = 2). Meanwhile, the delta value of δ30/28SiNBS 28 = 1.679(17)‰ was obtained (k = 2).

High-Resolution Atomic Absorption Spectrometry Combined With Machine Learning Data Processing for Isotope Amount Ratio Analysis of Lithium.

An alternative method for lithium isotope amount ratio analysis based on a combination of high-resolution atomic absorption spectrometry and spectral data analysis by machine learning (ML) is proposed herein. It is based on the well-known isotope shift of approximately 15 pm for the electronic transition 22P←22S at around the wavelength of 670.8 nm, which can be measured by the state-of-the-art high-resolution continuum source graphite furnace atomic absorption spectrometry. For isotope amount ratio analysis, a scalable tree boosting ML algorithm (XGBoost) was employed and calibrated using a set of samples with 6Li isotope amount fractions, ranging from 0.06 to 0.99 mol mol-1, previously determined by a multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS). The calibration ML model was validated with two certified reference materials (LSVEC and IRMM-016). The procedure was applied toward the isotope amount ratio determination of a set of stock chemicals (Li2CO3, LiNO3, LiCl, and LiOH) and a BAM candidate reference material NMC111 (LiNi1/3Mn1/3Co1/3O2), a Li-battery cathode material. The results of these determinations were compared with those obtained by MC-ICP-MS and found to be metrologically comparable and compatible. The residual bias was -1.8‰, and the precision obtained ranged from 1.9 to 6.2‰. This precision was sufficient to resolve naturally occurring variations, as demonstrated for samples ranging from approximately -3 to +15‰. To assess its suitability to technical applications, the NMC111 cathode candidate reference material was analyzed using high-resolution continuum source atomic absorption spectrometry with and without matrix purification. The results obtained were metrologically compatible with each other.

Investigation of mass-scale drift effects in the milli-mass range: Influence on high mass resolution mode multicollector-inductively coupled plasma mass spectrometer isotope ratio measurements.

The consequences, possible origins, and prevention of mass-scale drifts in the high mass resolution mode (HR, M/ΔM ≈ 8000) under constant conditions were investigated and simulated in case of a multicollector-inductively coupled plasma mass spectrometer (MC-ICP-MS) using silicon enriched in 28 Si as the main element in this survey. A drifting mass scale strongly impairs the precise and accurate determination of isotope ratios, depending especially on the peak/plateau width. For example, 29 Si+ in Si highly enriched in 28 Si has an extremely small mass plateau width of ΔM ≤ 4 × 10-3 u, compare ΔM(56 Fe+ ) ≈ 18 × 10-3 u, which is to our knowledge one of the smallest plateaus routinely investigated in isotope ratio measurements, thus requiring extreme stability. During warm-up of the double-focusing sector field mass spectrometer, a mass drift up to ΔM/Δt ≥ 0.006 u/hr has been observed. Long-term studies on mass scale stability and simulations concerning fluctuations of the magnetic field B, acceleration voltage Uacc and ESA voltage UESA are reported. A change of one of these quantities of 0.01% induces changes of the mass scale of 6 × 10-3 u, 3 × 10-3 u, and 1 × 10-3 u in the case of B, Uacc , and UESA , respectively. After identifying electrical charging/discharging effects in the mass spectrometer affecting the mass scale stability, the instrument was completely dismantled and carefully reinstalled. Additional stability tests using silicon, strontium, and lead finally yielded a mass drift of ΔM/Δt ≤ 0.001 u/8 h in the case of silicon. This enhanced stability guarantees measurements of isotope ratios on smallest plateaus with lowest uncertainty. The importance of a stable mass scale is pointed out and the relevant quantities of a typical magnetic sector field mass spectrometer are discussed.

Potassium isotopic composition of various samples using a dual-path collision cell-capable multiple-collector inductively coupled plasma mass spectrometer, Nu instruments Sapphire

Mass-dependent K isotopic fractionations can be used to trace cosmochemical, geological, and biological processes such as evaporation/condensation, core formation, magmatic processes, weathering, and cellular metabolism. However, the application of stable K isotopes has been limited by major isobaric interferences from Ar, common on conventional multi-collector inductively-coupled-plasma mass-spectrometer (MC-ICP-MS), particularly for the low-K samples. Here, we present a set of high-precision K isotopic data acquired on terrestrial rocks, seawater, as well as a lunar meteorite using the recently released Nu Sapphire™ MC-ICP-MS that utilizes a collision cell to minimize Ar based interferences while maintaining remarkably high K sensitivity (≈ 2000 V/ppm). The influence of several parameters on the precision and accuracy of the K isotopic data has been evaluated, including total K concentration, K intensity mismatch between sample and standard, HNO3 molarity mismatch between sample and standard, and the presence of matrix elements. We found that the Nu Sapphire™ can be used to acquire precise and accurate data using as little as 125 ng of K, which represents an improvement by a factor 10 compared to what has been done on previous instruments. We present data for 23 previously analyzed samples; these data are highly consistent with literature values. On the other hand, accurate measurements are conditioned 1) to the close matching of sample and standard K intensities (a 1% mismatch creates a 0.02‰ offset on the 41K/39K ratio), and 2) to the absence of Ca (a Ca/K ratio of 1% creates a 0.069‰ offset on the 41K/39K ratio). In addition, Rb/K, Na/K, Ti/K and Cr/K ratio should also be maintained under 2.5% to avoid isotopic offset.We confirm the existence of significant mass-dependent K isotopic variations in terrestrial samples and that lunar rocks are isotopically heavier than terrestrial rocks. The incomparable sensitivity offered by the Nu Sapphire opens the possibility for high-precision K isotopic measurements across a wide range of samples for diverse applications.

Tracing geographical origin of Lambrusco PDO wines using isotope ratios of oxygen, boron, strontium, lead and their elemental concentration

Wine identification is one of the most important aspects in the classification of wines and consumer protection. In particular, assuring wine authenticity is a crucial issue on which researchers are focusing on. This study aims to evaluate the feasibility of using chemical (B, Pb and Sr concentration) and isotopic compositions (δ11B, 20yPb/20xPb, 87Sr/86Sr and δ18O) of wine samples to trace their geographic origins. Different PDO Lambrusco wines coming from a confined area of northern Italy were analyzed and all the isotopic systematics were monitored by using a multi collector inductively coupled plasma mass spectrometer (MC-ICP/MS).The obtained results showed that boron isotope ratio measurements led to a satisfactory degree of accuracy and precision (measured value, n = 28, 11B/10B of NIST SRM 951a equal to 4.04343 ± 0.00178, (u = 2s) with a certified value of 4.04362 ± 0.00136 (u = 2s). Furthermore, in the present study, it has been possible to highlight significant differences among samples by means of one-way analysis of variance (ANOVA) and post hoc Tukey-Kramer test. Finally, Principal Component Analysis (PCA) was also carried out in order to evaluate to which extent the different PDOs can be distinguished from each other, taking into account the whole set of geographical origin descriptors. Although δ11B provided more sensitive information, the obtained results highlighted the important to consider the synergistic combination of all the investigated parameters to trace the different samples and the need to combine the obtained values with the same parameters evaluated in the soil, water and fertilizer as well.

Determination of Plutonium and Uranium Radionuclides in Glacier Ice Samples by MC-ICP-MS

A radiochemical procedure for the determination of plutonium (Pu) and uranium (U) radionuclides in ice samples by multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS) is presented. Pu and U radionuclides are preconcentrated by coprecipitation and then separated by extraction chromatography. The purified Pu and U fractions are analyzed by MC-ICP-MS. Detection limits of 2 × 10 -3 and 3 × 10-6 mBq kg-1 were achieved for 239Pu and 236U, respectively. Surface ice samples collected from the Gauli glacier (Switzerland) were analyzed by this method. The surface of the Gauli Glacier retains historical records of 239Pu, 240Pu and 236U from the nuclear weapon testing (NWT) period. Pu and U radionuclides were found to be consistent in terms of pattern, showing two peaks possibly related to the two main periods of the NWTs (1954-1958 and 1961-1963). ³H measurements, also released by the NWT, further confirmed the Pu and U results. The 240Pu/239Pu ratio ranged from 0.14 to 0.25, and 236U/ 239Pu ranged from 0.14 to 0.81. The Pu atom ratios ranged within the limits of global fallout in the most intensive period of NWT (1952 to 1962).

Nickel isotopes and rare earth elements systematics in marine hydrogenetic and hydrothermal ferromanganese deposits

Attention is now being given to Ni isotope systematics in hydrogenetic marine ferromanganese (Fe-Mn) crusts as paleoceanographic proxies. Previous work focused on identifying both mineralogy (post-depositional) and source effects (Gall et al. 2013; Gueguen et al. 2016), in particular regarding hydrothermal inputs in the oceans and the response of Ni isotope biogeochemical cycling through time. The most important sink for Ni in the oceans is the Fe-Mn oxides sink, but estimation of its Ni isotope composition is only based on hydrogenetic Fe-Mn crusts. In this study, we investigated a range of Fe-Mn deposits including Fe-Mn deposits variably affected by hydrothermal inputs, including hydrothermal deposits from the Lau back-arc basin (South West Pacific) and Lo'ihi seamount (Hawaii), hydrogenetic crust and nodules from the Bauer Basin (Pacific Ocean). Nickel isotope ratios were measured by multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS) using a double-spike (61Ni and 62Ni) correction method. The combination of Ni isotopes and rare earth element (REE) geochemistry show that Ni isotope fractionation in Fe-Mn deposits is essentially controlled by formation processes of the deposits (such as the rate of formation, the initial Mn-phase and sorption processes) which are also related to the depositional environment. Consistent with previous studies, pure hydrogenetic crusts are characterized by isotopically heavy Ni isotope signatures (δ60/58Ni values range from ‰ 0.9 and 2.5‰) and well-developed positive Ce anomalies. In contrast, mixed hydrothermal‑hydrogenetic crust and nodules from the Bauer Basin (East Pacific) display negative Ce anomaly and lighter δ60/58Ni values (0.3‰ to 0.4‰), which are interpreted as the result of far-field hydrothermal inputs of Fe-Mn precipitates from the East Pacific Rise.Nickel in hydrothermal deposits from the Lau Basin (0.5 and 1.1‰) and Lo'ihi seamount (−0.8 to −1.5‰) is isotopically lighter than in hydrogenetic Fe-Mn crusts. Light δ60/58Ni values in Lo'ihi deposits is due to the removal of Ni during Ni adsorption from seawater and from the hydrothermal fluid (between 0 and 1.4‰) on Fe-oxides followed by isotope fractionation between the fluid and the mineral phase. Results suggest that Ni isotopes in hydrothermal Fe-rich deposits are strongly fractionated relative to the seawater/fluid source due to partial removal of Ni on Fe-phases. Hydrothermal Mn-oxides deposits from the Lau Basin acquired their Ni isotope signature through Ni adsorption and continuous exchange of Ni with seawater. We propose that the systematic difference in Ni isotope signatures between hydrogeneous and hydrothermal Fe-Mn deposits is related to the mechanisms of Ni uptake into oxide minerals (e.g., birnessite vs. todorokite; Fe-oxides vs. Mn-oxides) which depend on the rate of formation and the source of Mn and Fe to marine ferromanganese deposits (i.e., depositional environment) rather than Ni sources.