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A prefiltering system made up of a double-Wien filter and a collision/reaction cell is included with the new Neoma MC-ICPMS/MS to reduce spectral interferences and allow high-precision isotope analyses. In the present study, we challenge these capabilities for measuring Sr isotopes. We first test the effect of different combinations of magnetic and electrostatic field values in the double-Wien filter on the transmission of a bandpass window that includes Sr isotopes and their reaction products. We next scrutinize the spectrum of ion products resulting from the introduction of N2O or SF6 to remove on-line Rb which interferes with Sr on the 87-mass unit. While N2O is the preferred reaction gas when using ICPMS/MS, we found that it reacts with Sr to create expected Sr16O products, but also 14N- and, most probably, 18O-based interfering products. By contrast, the introduction of SF6 generates a more resolved spectrum of F-based products, notably because F is mono-isotopic, but leads to a 50% reduction in signal intensity. Care must, however, be taken to measure 88SrF+ in a mass range free of the 32S19F316O+ interference. We then measure the 87SrF/86SrF ratio first in raw solutions of a suite of geological reference materials without prior Sr extraction and second in sintered in-house materials and natural solid samples using laser ablation. In the solution mode, no RbF+ is detectable and the sensitivity is ∼50 V ppm−1 for 88SrF+. The accurate measurements of the 87SrF/86SrF ratio of the geological reference materials are achieved with an uncertainty of 70 ppm (±2 SD), which is comparable with that typically obtained using MC-ICPMS with prior Sr extraction. In the laser ablation mode, the performance without SF6 of the Neoma for measuring Sr isotopes in homogeneous materials is roughly equivalent to that of the Neptune MC-ICPMS. With SF6, the Neoma MS/MS exhibits a sensitivity of ∼8 mV ppm−1 (based on 88SrF) and the measurement of the 87SrF/86SrF ratio has a short-term external precision of ∼0.0015 (±2 SD). Finally, an analysis of a heterogeneous material (a fossil tooth) reveals more well-resolved spatial variations of the 87SrF/86SrF ratio than of the 87Sr/86Sr ratio, likely thanks to the absence of 87RbF+. [ABSTRACT FROM AUTHOR]

Rationale: Understanding the interactions between marine mammals and their environment is critical for ecological and conservation purposes. Odontocetes offer a continuous record of their life history from birth as recorded in annual increments of their tooth dentine. Because dentine is not remodeled and contains collagen, nitrogen stable isotope compositions (δ15N) reflect nursing and weaning events, life history traits that would otherwise be impossible to retrieve in such elusive marine animals. Yet, capturing the magnitude and temporal changes in these events is constrained by tooth size and sampling resolution. Moreover, historical and fossil specimens undergo collagen decay, hence the need to develop the measurements of other proxies. Methods: Here, we present a multiproxy approach to investigate the use of Ca isotope compositions (δ44/42Ca) in relation to δ15N and laser ablation profiles for different trace metal (Ba, Mg, Sr, Zn) concentrations across the dentine of a single individual of the common bottlenose dolphin Tursiops truncatus. Results: To help interpret the dentine data, we provide milk elemental compositions and δ44/42Ca values for two odontocete individuals. We discuss the observed changes in δ44/42Ca across the dentine as potential markers of birth, weaning interval, incidental ingestion of seawater, trophic level and physiology. Incidental ingestion of seawater during nursing induces a positive offset in δ44/42Ca values recorded in the early formed dentine. Conclusions: Life history parameters of individual marine mammals are extremely difficult to retrieve due to limitations in observing specimens in the wild and the methodology presented here offers new ecological and paleoecological perspectives. [ABSTRACT FROM AUTHOR]

The new Neoma MC-ICPMS/MS is equipped with a prefiltering system consisting of a double-Wien filter and a collision/reaction cell whose performances are challenged using different combinations of magnetic and electrostatic field values and adjustable slit apertures. The results show an asymmetrical attenuation of transmission relative to the chosen axial mass-to-charge value, with higher efficiency at removing low masses than high masses, even when magnetic induction is minimal. The resulting asymmetry of the bandpass window is fully predictable by theoretical calculations of ion trajectories in a Wien filter, either as a function of the magnetic field value or that of the aperture of the adjustable slit. With an axial mass-to-charge value set at 120Sn, the vertical deviation for a magnetic field value at 100% will be approximately 3 mm and 4 mm for a variation of mass-to-charge of ±20%, respectively. In these conditions, Ar was already barely detectable with the lowest magnetic field value (10%) and a fully open adjustable slit, while Pb is quantitatively transmitted. We then use the prefiltering system to remove on-line the 40Ar23Na+ compound that produces an isobaric interference with 63Cu, hampering high-precision measurement of Cu stable isotope composition (65Cu/63Cu). While Na is not transmitted thanks to the double-Wien filter, 40Ar23Na+ still interferes with 63Cu, demonstrating that this argide is produced in the plasma source but not in the reaction cell. Helium in the collision/reaction cell is necessary to remove the 40Ar23Na+ interference. The MS/MS technology of the Neoma allows for the correction of the 40Ar23Na+ interference up to a Na/Cu ratio of 10, where other classic MC-ICPMS already show an offset of the Cu stable isotope composition for a Na/Cu ratio of 1. The inability to correct the Cu stable isotope composition with a Na/Cu ratio higher than 10 suggests that the Na-based interference is no longer spectral and becomes linked to the matrix. We next measure the Cu stable isotope composition in eight certified reference materials prepared with a simple automated single step ion-chromatography procedure to purify Cu. The results show a very good agreement with previously reported values. The overall results suggest that the MS/MS technology of the Neoma MC-ICPMS allows efficient on-line isolation of analytes, therefore reducing potential spectral and matrix interferences to permit much better resolved and controlled subsequent effects in the collision/reaction cell. [ABSTRACT FROM AUTHOR]

It has been proposed that gold purification by cementation could account for the low gold content of ancient Greek coinage from Attica and the Cyclades. In order to place new constraints on this suggestion, the concentrations of platinum-group elements (PGEs) and gold have been measured in 72 silver coins mostly from the Greek Archaic and Classical periods, but also from Rome, India, medieval Europe, and colonial Spanish Americas, by inductively coupled plasma mass spectrometry. A novel technique allowing these concentrations to be determined in silver coins is described. Variations are consistent with element position in the periodic table. The volatile elements Rh and Os are commonly at or below the detection level, which may reflect evaporation during smelting and cupellation. Ruthenium and Ir, which binary phase equilibrium experiments show to be insoluble in solid silver and gold, and soluble Pd and Pt, show variations in coinage consistent with these properties. The dichotomy of Ir/Au ratios is not consistent with Ir loss in gold during salt cementation (parting) and is better explained by the contrast between Au-rich and Au-poor ore districts. This contrast is suggested to reflect either regional differences or the variability of conditions during ore genesis, such as hydrothermal solution chlorinity. [ABSTRACT FROM AUTHOR]