Mass Bias Correction Research Articles

Reliability Evaluation for Mercury Stable Isotope Ratio Measurement by MC-ICP/MS

This study assessed the reliability of Mercury (Hg) stable isotope ratio measurements using MC-ICP/MS hyphenated with three different systems: wet plasma, dry plasma, and a cold vapor generator (CVG). Precision measurements using wet plasma improved with concentration, showing a range of 0.4 - 10.0% at 100 µg/L, with corresponding accuracy from 0.0 – 0.4%. By contrast, dry plasma demonstrated precision between 0.02 - 2.2% at 10 µg/L for 202/198Hg, with accuracy ranging from 1.2 - 1.4%. The CVG system, however, displayed significantly enhanced accuracy, from 0.2% for 199/198Hg to 0.9% for 204/198Hg at 0.1 µg/L. The study also incorporated a mass bias correction using a thallium (NIST 997 standard) internal spike, emphasizing the importance of maintaining a total Hg beam above 0.5 V to ensure measurement precision and accuracy. The findings suggest that the CVG method is most suitable for environmental samples with trace Hg concentrations, while both dry and wet plasma systems can serve effectively at higher concentrations (≥ 100 µg/L), given their analytical convenience and performance.

"Characterization of a New Iron Isotopic Reference Material Using Two Independent Methods for Instrumental Mass Bias Correction "

"Characterization of a New Iron Isotopic Reference Material Using Two Independent Methods for Instrumental Mass Bias Correction "

Implementation and experience of using methods for analyzing the isotopic composition of Sm and Nd, Rb and Sr in rock samples at the Geoanalitik Center for Collective Use

Research subject. AGV-2 and BHVO-2 geochemical reference materials for studying the Sm, Nd and Rb, Sr isotope systems along with various rocks and mineral samples. Materials and Methods. An analysis of the isotopic composition of Sm, Nd and Rb, Sr was carried out using Neptune Plus and Triton Plus mass spectrometers. Aim. To implement analytical techniques for the isotopic composition of Sm and Nd, Rb, and Sr in various rock and mineral samples using two types of multicollector mass spectrometers – inductively coupled plasma NeptunePlus and thermal ionization TritonPlus (Thermo-Fisher), as well as a description of the procedure of processing experimental data and the experience in using techniques at the “Geoanalitik” shared research facilities of the IGG UB RAS for the period 2015-2023. Results. The analytical techniques implemented included (1) column chromatography using various ion-exchange resins, optimised for the ratio of labour costs/quality of analytical results; (2) the measurement of isotope ratios using two types of mass spectrometers; (3) the correction of mass bias of isotope ratios and the determination of Sm and Nd, Rb, and Sr concentrations by the isotope dilution method using 149Sm+150Nd and 85Rb+84Sr spikes. Testing of the techniques was carried out using the AGV-2 and BHVO-2 geochemical reference materials; their metrological characteristics were presented. When using TritonPlus, the reproducibility (BHVO-2, n=60) of measurements of 143Nd/144Nd, 147Sm/144Nd isotope ratios and Sm and Nd concentrations are ±0.000020, ±0.0004, ±1.3 and ±0.4, respectively; indicators of correctness of determining the ratios 143Nd/144Nd and 147Sm/144Nd – 0.001 and 0.25% and concentrations of Sm and Nd – 2%; the reproducibility (BHVO-2, n=63) of measurements of 87Sr/86Sr, 87Rb/86Sr isotope ratios and concentrations (Rb and Sr) are ±0.0025%, ±1.5%, ±2%, respectively. The uncertainty of a single measurement of the 143Nd/144Nd and 87Sr/86Sr isotope ratio, represented by the standard error of the average single measurement in the sample, does not exceed 0.0025%. Conclusions: the results obtained for the geochemical reference materials are in satisfactory agreement with those provided in the GeoReM database, as well as with the certified values provided by the United States Geological Survey (USGS). The described analytical techniques are used at the “Geoanalitik” shared research facilities of the IGG UB RAS to analyse various rock and mineral samples. The work presents a number of experimental results obtained, which are subsequently used in geochronological applications.

Unravelling the collision scenario of the dissociative galaxy cluster Abell 56 through hydrodynamic simulations

ABSTRACT In galaxy cluster collisions, the gas can be separated from dark matter haloes. Abell 56 displays signatures of a dissociative bullet-like merger with a possible high-inclination angle between the plane of orbit and the sky. Our objective is to provide a comprehensive description of the features observed in the collision scenario of Abell 56. Additionally, we aim to apply a potential weak lensing mass bias correction attributed to the merger to evaluate its impact on our findings. To investigate this, we perform tailored hydrodynamical N-body simulations, varying the impact parameter. We initially identified an early scenario at 0.12 Gyr after the central passage that reproduces some observational features. However, the mean temperature of 9.7 keV exceeded the observed value. Our best model corresponds to the late scenario at 0.52 Gyr after the pericentre, reproducing observed features of Abell 56, with an inclination of 58°. These features include the offset of 103 kpc between the main gas density peak and the south dark matter density peak, gas morphology, a line-of-sight relative velocity of 184 km s−1, and a mean temperature of 6.7 keV. This late model provides a plausible scenario to describe the dynamics of Abell 56. The weak lensing mass bias did not significantly impact the overall dynamics of this cluster merger.

Comparison of different mass bias correction procedures for the measurement of mercury species-specific isotopic composition by gas chromatography coupled to multicollector ICP-MS

When dealing with transient signals, such as those obtained from the coupling of gas chromatography with MC-ICP-MS, mass bias has a higher impact on isotope ratio accuracy and precision than when working with continuous signals.

The Combined Power of Double Mass Curves and Bias Correction for the Maximisation of the Accuracy of an Ensemble Satellite-Based Precipitation Estimate Product

Precise estimation of the spatial and temporal characteristics of rainfall is essential for producing the reliable catchment response needed for proper management of water resources. However, in most parts of the world, gauged rainfall stations are sparsely distributed and fail to properly capture the spatial variability of rainfall. Furthermore, the gauged rainfall data can sometimes be of short length or require validation. Following this, we present a procedure that enhances the trustworthiness of gauged rainfall data and the accuracy of the rainfall estimations of five satellite-based precipitation estimate (SPE) products by validating them using the 1779 gauged rainfall stations across Thailand. The five SPE products considered include CMORPH-BLD; TRMM-3B42; CHIRPS; CHIRPS-PL; and TRMM-3B42RT. Prior to validation, the gauged rainfall dataset was verified using double mass curve (DMC) analysis to eliminate questionable and inconsistent readings. This led to the improvement of the Nash–Sutcliffe Efficiency (NSE) between the station of interest and its surroundings by 13.9% (0.758–0.863), together with an average 11.8% increase with SPE products, whilst dropping only 7% of questionable dataset. Three different bias correction (BC) procedures were applied to correct SPE products using gauge-based gridded rainfall (GGR). Once DMC and BC procedures were implemented together, the performance of the SPE products was found to increase significantly. Finally, the application of the ensemble weighted average of the three best-performing bias-corrected SPE products (Bias-CMORPH-BLD, Bias-TRMM-3B42, and Bias-CHIRPS) further enhanced the NSE to 0.907 and 0.880 in calibration and validation time periods, respectively. The proposed DMC-based correction SPE and the weighting procedure of multiple SPE products allows for an easy means of obtaining daily rainfall in remote locations with sufficient accuracy.

Rubidium Isotope Ratios of International Geological Reference Materials

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.

A new procedure for separating thallium from geological materials prior to stable isotope ratio determination by MC–ICP–MS

In this paper, a simple and efficient method is presented for the separation of Tl from various complex geological samples and subsequent accurate and precise Tl isotope measurements by multi-collector inductively coupled plasma–mass spectrometry (MC–ICP–MS). Chemical separation involves a two-stage tandem column method with tributyl phosphate (TBP) extraction resin and AG50W-X12 cation ion-exchange resin, which efficiently separate Tl from the matrix, interfering elements, and sulfate ions. External normalization to NIST SRM 981 Pb and standard–sample bracketing using NIST SRM 997 Tl were utilized for the instrumental mass bias correction. The ε205TlNIST 997 data are reported as the per 104 deviation of 205Tl/203Tl from NIST SRM997 (Rehkämper and Halliday, 1999; Vaněk et al., 2016). The overall external precision for the ε205TlSRM 997 values is estimated to be ±0.6 (2SD; n > 1000) and ± 0.8 (2SD; n = 5) based on repeated analyses of NIST SRM 997 and the geological reference material NOD-A-1, respectively. The Tl isotopic compositions of nine well-documented geological reference materials are in good agreement with the values reported in previous studies, confirming the validity of our new analytical procedure for the accurate determination of Tl stable isotopic compositions of geological samples.

Copper isotope delta measurements in high purity materials: CCQM-P213 pilot study

Main textAccurate and precise isotope ratio measurements of heavy elements are playing an increasingly important role in modern analytical sciences and have numerous applications. Today, isotope ratio measurements are typically performed with two principal techniques: thermal ionization mass spectrometry (TIMS) and multiple collector-inductively coupled plasma mass spectrometry (MC-ICP-MS). To obtain accurate results by mass spectrometry, isotopic certified reference materials (iCRMs) are needed for mass bias correction and for the validation of the method used for analysis. Thus, it is of paramount importance to achieve measurement comparability of all data reported, and to assess measurement capability of each CRM producer/National Metrology Institute (NMI). Therefore, the international comparison (CCQM-P213) was performed to assess the analytical capabilities of NMIs for the accurate determination of copper isotope ratio delta values in high purity materials. The study was proposed by the coordinating laboratories National Research Council Canada (NRC), National Institute of Standards and Technology (NIST), Bundesanstalt für Materialforschung und -prüfung (BAM) and Physikalisch-Technische Bundesanstalt (PTB) as an activity of the Isotope Ratio Working Group (IRWG) of the Consultative Committee for Amount of Substance - Metrology in Chemistry and Biology (CCQM). Participants included six NMIs and one designated institute (DI) from the six countries. Although no measurement method was prescribed by the coordinating laboratories, MC-ICP-MS with either standard-sample bracketing (SSB) or combined SSB with internal normalization (C-SSBIN) models for mass bias correction were recommended. Results obtained from the six NMIs and one DI were in good agreement.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Mass Bias Corrections for Hydrogen and Oxygen Isotope Analysis of Tourmaline by Secondary Ion Mass Spectrometry

ABSTRACT Hydrogen (δ2H) and oxygen (δ18O) stable isotopes are used to trace fluid sources, metals, and contaminants in the environment and Earth's subsurface. Tourmaline-supergroup minerals provide an opportunity to quantify both δ2H and δ18O from the same grain using in situ analytical techniques (e.g., Secondary Ion Mass Spectrometry – SIMS). These minerals occur in a wide variety of geological environments and have a wide range of chemical compositions. However, large differences in chemical composition are problematic during SIMS analysis, as instrumental mass fractionation (IMF) often varies with the chemical composition of the mineral. Therefore, calibration models derived by analyzing tourmalines of different chemical composition must be developed for accurate analysis by SIMS. Hydrogen and oxygen isotope analysis was done on six reference tourmaline samples using a CAMECA 7f SIMS instrument operating at extreme energy filtering. Spot-to-spot repeatability for tourmalines was in the range 4–5‰ and 0.6–1.0‰ for δ2H and δ18O, respectively. There is a strong correlation between IMF and several elements (B, Si, Ca, Fe, and Fe#). Iron content is the most robust predictor of IMF, and we report two calibration curves for the correction of δ2H and δ18O measured by SIMS using reference tourmaline crystals with different Fe contents, ranging from 0.00 to 14.00 wt.% Fe. This is the first calibration curve used to correct for the fractionation of hydrogen isotope ratios in tourmaline as measured by SIMS. Tourmaline-supergroup minerals require a suite of at least three, with a range of Fe content, to ensure accurate and precise H and O analysis by SIMS. Crystallographic orientation effects were not observed for these tourmalines.

Determination of the Isotopic Composition of Ytterbium by MC-ICP-MS Using an Optimized Regression Model.

In this study, we measure the absolute isotope ratios of ytterbium (Yb) by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) using an optimized regression model for mass bias correction. A rhenium (Re) reference material (NIST SRM 3143), which has been characterized previously, is selected as a primary calibrator to calibrate the absolute Yb isotope ratios for three Yb materials (GSB, Alfa Yb, and GBW). The three-isotope plot for all collected data indicates that the results of Yb isotope ratios obtained are not affected by any polyatomic interferences and the mass-independent isotopic fractionation. Furthermore, the recalibrated Hf historical isotope ratios by using the absolute Yb isotopic composition obtained in this study for the isobaric interference correction on Hf isotopes are in agreement with the original historical values. This work has further demonstrated the applicability of the regression model for the calibrated measurements of absolute isotope ratios using MC-ICP-MS. The three mono-elemental Yb standard solutions are thus proposed as the reference materials for Yb isotope ratio measurements in environmental and geoscience applications.

THE METHOD FOR Cu AND Zn ISOTOPE RATIO DETERMINATION BY MC ICP-MS USING THE AG MP-1 RESIN

The isotopic composition of copper is of great interest for researchers in various fields of science, geochemistry and hydrology in particular, wherein the consideration is being given to the variations in the isotopic composition of the Earth’s crust, extraterrestrial matter, and water basins, as well as to the origin and transfer of matter. Zn isotopes appear to be promising for identifying the sources and pathways of the environmental pollution. The aim of this study involves the refinement and validation of the zinc and copper isotopic ratio determination methodology covering the whole process from sample digestion to MC ICP-MS measurements. For this reason, as well as to assess the suitability of the methodology for the analysis of environmental samples, Zn and Cu isotopic analysis of the BHVO-2, BCR-2 and AGV-2 USGS certified reference materials has been performed. The method for determination of Cu and Zn stable isotope ratios by multi-collector inductively coupled plasma mass spectrometry in environmental samples is developed. The application of the AG MP-1 resin with optimized layer parameters (resin bed height 3.5 cm, diameter 1 cm) provides the high-purity Cu and Zn fractions. The method is characterized by high throughput and adequate analytical figures of merit when using the standard-sample bracketing technique for mass bias correction. The procedural blanks related to chemical dissolution and ion exchange procedures are lower than 1 and 3 ng for Cu and Zn, respectively, assuring no blank effect on the isotopic composition of samples. The accuracy and precision obtained for Cu and Zn isotope measurements in the BHVO-2, BCR-2 and AGV-2 geological certified reference materials demonstrate good agreement with the reference values published.

An improved calibrated mass spectrometry for absolute copper isotope-ratio measurement using two strategies for mass bias correction factor

Modern advances in multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) have greatly promoted the investigation of copper isotopes in various research fields. To meet the demand, an improved calibrated mass spectrometry for the absolute determination of copper isotopic composition was developed in this study. The method has made progress in the investigation of instrumental mass bias correction factor for copper isotopic analysis using MC-ICPMS through employing two independent strategies. One is the conventional mathematical iterative method based on the MC-ICPMS measurement data; the other one is direct calculation using the absolute copper isotopic compositions in isotopically enriched 63Cu and 65Cu materials by developing a TE-TIMS method. The results of Kiter = 0.95563(16)k = 1 and KTE = 0.95551(17)k = 1 were consistent in their standard uncertainties, demonstrated the first cross-validation of these two strategies. Thereafter, the proposed calibrated mass spectrometry were applied to re-measure the copper isotope amount ratios in three isotopic reference materials, resulted in RNIST SRM 97665/63 = 0.44547(16)k = 2, RERM®−AE63365/63 = 0.44549(16)k = 2, and RERM®−AE64765/63 = 0.44557(16)k = 2, respectively. These expended uncertainties were only one third or one fifth of the stated uncertainties in their certificates. Furthermore, the absolute copper isotopic compositions in four natural-abundance samples and a new copper isotopic reference material GBW04624 were determined, given an average atomic weight of copper as Ar(Cu) = 63.5456(4)k = 2. The δ65Cu values of GBW04624 relative to NIST SRM 976, ERM®-AE633 and ERM®-AE647 were also applied by implementing the C-SSBIN calibration model. This provides an additional independently certified and SI-traceable copper isotopic reference material, in support of various scientific researches.

High-Precision Fe Isotope Analysis On MC-ICPMS Using A 57Fe-58Fe Double Spike Technique

Herein we report procedures based on multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) for high-precision Fe isotopic analysis using a 57Fe-58Fe double spike technique. Iron purification was achieved using AG1-X8 in HCl media following previously or newly established procedures. In the new procedure, smaller columns with 4 mm diameter were used, containing 0.4 mL AG1-X8, thus greatly reducing the operation time and the amount of acid and resin consumed compared to the previously established method using 1 mL resin. Potential trace Ni interference on 58Fe was suppressed by increasing the total Fe ion intensity to ≥ 120 V. Measurements of GSB Fe solutions doped with mono-elements demonstrated that a mass bias correction by the 57Fe-58Fe double spike was robust if Ca/Fe ≤ 1.0, Al/Fe ≤ 1.0, Cu/Fe ≤ 1.0, Co/Fe ≤ 0.1, Ni/Fe ≤ 10-4, and Cr/Fe ≤ 10-4. Monitoring of pure Fe standard solutions, viz. IRMM-014 and NIST3126a, and geological reference materials, viz. JP-1, BHVO-2, W-2a, GSP-2, and COQ-1, over nine months yielded δ56Fe (relative to IRMM-014) values of 0.003 ± 0.013‰ (2 SD, N = 20), 0.368 ± 0.011‰ (2 SD, N = 30), 0.019 ± 0.018‰ (2 SD, N = 15), 0.109 ± 0.017‰ (2 SD, N = 30), 0.049 ± 0.018‰ (2 SD, N = 17), 0.155 ± 0.018‰ (2 SD, N = 14), and -0.066 ± 0.022‰ (2 SD, N = 20), respectively, consistent with the recommended values within quoted errors. Based on repeated analyses of the standards, the long-term precision of our double spike method is better than 0.02‰ for δ56Fe on average, proving its ability to distinguish small isotope fractionation among high-temperature samples.

Evaluation of plasma condition, concentration effect, position effect, and nickel-doping method on non-matrix-matched Fe isotopic analysis by femtosecond laser ablation multi-collector inductively coupled plasma mass spectrometry

This study investigated the influences of plasma condition, concentration effect, ablation position and on-line addition of an aqueous Ni standard for non-matrix-matched Fe isotopic analysis by femtosecond laser ablation multi-collector inductively coupled plasma mass spectrometry (fs LA–MC–ICP–MS). Deviations up to ~0.7‰ in δ56Fe values caused by non-matrix-matched analyses were difficult to eliminate under dry plasma condition even with fs-LA. However, the nebulized water after the ablation cell efficiently reduces or eliminates the matrix-dependent fractionation of Fe isotopes without reducing signal intensity. Furthermore, concentration- and position-dependent fractionation of Fe isotopes was not observed under wet plasma condition. For instrumental mass bias correction, the standard–sample bracketing (SSB) method and SSB with Ni doping (SSB + Ni) were performed in the presence of nebulized water with fs LA–MC–ICP–MS. Results indicate that both the SSB and SSB + Ni methods are sufficient to correct for instrumental mass bias under wet plasma condition, with the SSB + Ni method being more effective in calibrating short-term fluctuations in mass bias with improved external reproducibility of ~0.15‰ (2SD) for δ56Fe values. Compared to SN–MC–ICP–MS, deteriorated precision offered by fs LA–MC–ICP–MS may represent a major limitation for some applications relying upon precise Fe isotope ratio measurements. This approach for non-matrix-matched analysis of Fe isotopes by fs LA–MC–ICP–MS under wet plasma condition combined with the SSB + Ni method allows for more flexibility in tracing detailed geological processes with large Fe isotope fractionation of a wide range of solids. Relatively precise and accurate Fe isotopic compositions of potential reference materials of Balmat pyrite (δ56Fe = −1.32 ± 0.12‰, δ57Fe = −1.91 ± 0.20‰; 2SD, n = 166) and PZH12–24 ilmenite (δ56Fe = −0.38 ± 0.15‰, δ57Fe = −0.57 ± 0.23‰; 2SD, n = 134) were obtained using this analytical protocol, consistent with reference values obtained by solution nebulization (SN)–MC–ICP–MS within analytical uncertainties (Balmat pyrite: δ56Fe = −1.30 ± 0.04‰, δ57Fe = −1.94 ± 0.07‰, 2SD, n = 3; PZH12–24 ilmenite: δ56Fe = −0.38 ± 0.06‰, δ57Fe = −0.55 ± 0.07‰, 2SD, n = 6).

Data processing made easy: standalone tool for automated calculation of isotope ratio from transient signals – IsoCor

A data processing application (App) IsoCor facilitating automatic calculation of isotope ratios from transient signals was introduced. IsoCor performs baseline subtraction, peak detection, mass bias correction, isotope ratio and delta calculation.

Size determination of nanoparticles by ICP-ToF-MS using isotope dilution in microdroplets

Combination of microdroplet generator and ICP-ToF-MS for nanoparticle sizing via on-line ID (on-line ID-MDG-sp-ICP-ToF-MS). 194Pt/195Pt ratio was used for sizing of the particles, while 182W/183W ratio used simultaneously for mass bias correction.

Analysis of solid uranium particulates on cotton swipes with an automated microextraction-ICP-MS system.

An automated microextraction method coupled to an inductively coupled plasma - mass spectrometer (ICP-MS) was developed for the direct analysis of solid uranium particulates on the surface of cotton swipes. The microextraction probe extracts particulates from the sample surface, in a flowing solvent, and directs the removed analyte to an ICP-MS for isotopic determination. The automated system utilizes a mechanical XY stage that is software controlled with the capability of saving and returning to specific locations and a camera focused to the swipe surface for optimal viewing of the extracted locations (i.e., material present). Here, particulates (n = 135) were extracted and measured by ICP-MS, including 35 depleted uranyl nitrate hexahydrate (UN) (used for mass bias corrections), 50 uranyl fluoride (UO2F2), and 50 uranyl acetate (UAc) particulates. Blank extractions were performed on the cotton swipes between triplicate sample analyses. Between each swipe extraction, the probe was sent between two wells containing 10% and 5% HNO3 to clean the probe head and to eliminate any analyte carryover between particulates. The measured 235U/238U and 234U/238U isotope ratios for the UO2F2 particulates were 0.00725(8) and 0.000054(4), a percent relative difference (% RD) of -0.041% and -1.7% from the reference isotope ratios determined in-lab through multi-collector ICP-MS analysis of dissolved aliquots of the U material. The UAc samples had a measured 235U/238U isotope ratio of 0.00206(7), a -0.96% relative difference from the reference value of 0.00208(1). The 234U/238U and 236U/238U isotope ratios were 0.000008(1) and 0.000031(4), -5.1% RD and -4.3% RD, respectively. The automated sample stage enabled seamless and rapid particle analysis, leading to a significant increase in throughput versus what was previously possible. Additionally, the saved location capability reduced user sampling error as sampling locations were easily stored and recalled. Analysis of U particles on the swipe surface - including blanks, mass bias, and triplicate extractions - was completed in less than an hour without any sample preparation necessary.

Is a Lead Isotope Ratios in Wine Good Marker for Origin Assessment?

Lead isotope ratio pattern (206Pb/207Pb, 208Pb/206Pb, 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb) was analyzed in 59 samples of Serbian wine, from four geographical regions. By utilization of powerful inductively coupled plasma mass spectrometry (ICP-QMS), lead isotope ratios were used as unique “fingerprint”, when combined with multivariate methods of analysis (Principal Component Analysis), provided information on the geographical origin of wine. In validation of ICP- QMS method and quantitative analysis, the certified reference material NIST SRM 981 was employed to test the mass-bias correction and thallium isotopes 203Tl and 205Tl (NIST SRM 997) as an internal standard. The obtained results were discussed in correlation with the corresponding values of LIRs of different European and Australian wines. In addition, the impact of anthropogenic Pb from different sources on the total Pb isotopic composition in Serbian wines was analyzed too. On the other side, the obtained values of Pb content were compared with the applicable health safety standards, according to the International Code of Oenological Practices.

Interferences and Matrix Effects on Iron Isotopic Composition Measurements by 57Fe-58Fe Double-Spike Multi-Collector Inductively Coupled Plasma Mass Spectrometry; the Importance of Calcium and Aluminum Interferences

Multi-collector inductively coupled plasma mass spectrometers (MC-ICPMS) are widely used for Fe isotope measurements. The latter may be perturbed by interferences (notably from Cr and Ni) and matrix effects (notably from major elements), caused by elements remaining in the samples after purification. We quantified some of these perturbations and our ability to correct them whenever possible, using Thermo Neptune and Neptune Plus MC-ICPMS with a 57-58Fe double-spike mass bias correction. 54Cr and 58Ni isobaric interference corrections were found to be extremely efficient up to Cr/Fe=0.12 and Ni/Fe=0.04 (g/g natural Fe). Matrix effects were found negligible up to at least Na/Fe=175, Mg/Fe=10, K/Fe=1.5, and Mo/Fe=75 (g/g natural Fe). 28Si2+ interference was found negligible up to Si/Fe=50. Finally, we found that calcium and aluminum could cause significant interferences (e.g., 40Ca16O and 27Al2+), for Ca/Fe ≥ 2.5 and Al/Fe ≥ 2.5. The perturbation intensity relative to the Ca/Fe ratio was found dependent on the measurement conditions (plateau width). While working with samples with potentially high calcium or aluminum contents (such as calcite minerals or tests, bones and teeth, or marine samples and crustal rocks), we recommend to carefully take into account Ca and Al while tuning the instrument and checking the measurement accuracy with isotopic standards (i.e., doping the isotopic standard with Ca and Al levels comparable to those of the samples).