Elemental fractionation effects in high repetition rate IR femtosecond laser ablation ICP-MS analysis of glasses

An IR-femtosecond laser ablation ICPMS coupling was used to investigate the influence of the high repetition rate on elemental fractionation effects for the analysis of silicate glass SRM NIST 610. First, elemental fractionation inherent to the ICP was minimised by working on wet plasma conditions which had greater tolerance to mass loading and demonstrated a higher robustness compared to dry plasma conditions. Because of the use of a narrow laser beam producing small craters (17 µm in diameter), a special arrangement of pulses was used to perform resulting craters of 100 µm diameter. The ablation strategy developed in this work consisted in a series of concentric circle trajectories ablated at high repetition rates by moving the laser beam rapidly thanks to a scanning beam device. Two scanner speeds (0.25 mm s−1 and 1.5 mm s−1), five laser repetition rates (from 0.1 kHz to 10 kHz) and three fluence values (5 J cm−2, 14 J cm−2, and 25 J cm−2) were investigated in detail. For this purpose, critical elemental ratios (namely 238U/232Th, 208Pb/238U, and 66Zn/65Cu) of aerosols produced by fs-LA of silicate glass were studied to evaluate the impact of the different laser parameters on elemental fractionation . No heating zones or preferential evaporation of elements were found depending on the repetition rate employed. However, particle-size-fractionation was measured during the ablation of the sample surface, and this effect was reduced by using a high repetition rate as well as a high scanner speed which allow the dilution of the large particles coming from the surface layer with finer particles coming to deeper levels. Additionally, the ablation rate induced by the selected ablation strategy had a low influence on fractionation effects due to the high robustness of the ICP plasma and, on the other hand, fractionation indices were not particularly affected by the laser repetition rate although they could be improved by the use of high fluence values. Finally, it could be stressed that no differences on the structure of the aerosol particles collected on membrane filters were found depending on the ablation parameters

Characterization of the aerosol produced by infrared femtosecond laser ablation of polyacrylamide gels for the sensitive inductively coupled plasma mass spectrometry detection of selenoproteins

A 2D high repetition rate femtosecondlaserablation strategy (2-mm wide lane) previously developed for the detection of selenoproteins in gel electrophoresis by inductively coupled plasma mass spectrometry was found to increase signal sensitivity by a factor of 40 compared to conventional nanosecond ablation (0.12-mm wide lane) [G. Ballihaut, F. Claverie, C. Pécheyran, S. Mounicou, R. Grimaud and R. Lobinski, Sensitive Detection of Selenoproteins in Gel Electrophoresis by High Repetition Rate FemtosecondLaserAblation-Inductively Coupled Plasma Mass Spectrometry, Anal. Chem. 79 (2007) 6874–6880]. Such improvement couldn't be explained solely by the difference of amount of material ablated, and then, was attributed to the aerosol properties. In order to validate this hypothesis, the characterization of the aerosolproduced by nanosecond and high repetition rate femtosecondlaserablation of polyacrylamidegels was investigated. Our 2D high repetition rate femtosecondlaserablation strategy of 2-mm wide lane was found to produce aerosols of similar particle size distribution compared to nanosecond laserablation of 0.12-mm wide lane, with 38% mass of particles < 1 µm. However, at high repetition rate, when the ablated surface was reduced, the particle size distribution was shifted toward thinner particle diameter (up to 77% for a 0.12-mm wide lane at 285 µm depth). Meanwhile, scanning electron microscopy was employed to visualize the morphology of the aerosol. In the case of larger ablation, the fine particles ejected from the sample were found to form agglomerates due to higher ablation rate and then higher collision probability. Additionally, investigations of the plasma temperature changes during the ablation demonstrated that the introduction of such amount of polyacrylamidegel particles had very limited impact on the ICP source (ΔT~ 25 ± 5 K). This suggests that the cohesion forces between the thin particles composing these large aggregates were weak enough to have negligible impact on the ICPMS detection

Trace Elements Analysis of Tunisian and European Extra Virgin Olive Oils by ICP-MS and Chemometrics for Geographical Discrimination

The aim of this study was to investigate the levels of trace elements in olive oils from different locations and their use for geographical authentication. Concentrations of seventeen elements were determined in a total of 42 olive oils from Tunisia, Spain (Basque country), and southern France, and in nine soil samples from Tunisia by quadrupole inductively plasma mass spectrometry. The compilation of appropriate techniques integrated into the analytical procedure achieved a precision (RSD) between 2% and 15% and low limits of detection (between 0.0002 and 0.313 µg kg−1). The accuracy of the analytical method applied for olive oil analysis was evaluated using SRM NIST 2387 Peanut butter. The recoveries obtained after microwave-assisted digestion for the certified elements ranged between 86% and 102%. Concentrations of non-certified elements (V, Cr, Co, Ni, Ba, Rb, Sr, Cd, Pb, and As) were presented. The use of Pearson correlation applied on paired Tunisian oil/soil samples has shown that several elements (Mg, Mn, Ni, and Sr) were significantly correlated. The multivariate statistics using principal component analysis have successfully discriminated against three studied origins. The most significant variables were the elemental concentrations of Cu, Cr, Fe, Mn, Sr, V, and Zn. This study shows the potential of applying trace elements profiles for olive oil geographical discrimination.This research was funded by European Project TunTwin from the Horizon 2020 Framework program of the European Union under grant No. 952306. It was also funded by the French ANR EquiPex MARSS project with a contribution of the METROFOOD ESFRI project. This work was partially supported by the Euskadi/Nouvelle Aquitaine/Navarra Eurorregion through the research project ISOTOPO (with agreement no. 2020/3). The financial support of a Ph.D. grant for Emna G. Nasr has been provided by the “Excellence Eiffel” scholarship of Campus France, the European project “TunTwin” and the scholarship “bourse d’alternance” of University Tunis El Manar, Ministry of Higher Education and Scientific Research in Tunisia

The stability of major and trace element concentrations from musts to Champagne during the production process

Thirty-nine Champagnes from six different brands originating from the AOC Champagne area were analyzed for major and trace element concentrations in the context of their production processes and in relation to their geographical origins. Inorganic analyses were performed on the must (i.e., grape juice) originating from different AOC areas and the final Champagne. The observed elemental concentrations displayed a very narrow range of variability. Typical concentrations observed in Champagne are expressed in mg/L for elements such as K, Ca, Mg, Na, B, Fe, A, and Mn. They are expressed in µg/L for trace elements such as Sr, Rb, Ba, Cu, Ni, Pb Cr and Li in decreasing order of concentrations. This overall homogeneity was observed for Sr and Rb in particular, which showed a very narrow range of concentrations (150 &lt; Rb &lt; 300 µg/L and 150 &lt; Sr &lt; 350 µg/L) in Champagne. The musts contained similar levels of concentration but showed slightly higher variability since they are directly influenced by the bedrock, which is quite homogenous in the AOC area being studied. Besides the homogeneity of the bedrock, the overall stability of the concentrations recorded in the samples can also be directly linked to the successive blending steps, both at the must level and prior to the final bottling. A detailed analysis of the main additives, sugar, yeast and bentonite, during the Champagne production process, did not show a major impact on the elemental signature of Champagne

Sr Isotopic Composition of NIES Certified Reference Material No. 28 Urban Aerosols

An interlaboratory study of the National Institute for Environmental Studies (NIES) certified reference material (CRM) No. 28 Urban Aerosols collected from the filters of a central ventilating system in a building in the Beijing city center from 1996 to 2005 was performed to obtain an information value of the Sr isotopic composition. The Sr isotopic composition was measured using multi-collector-inductively coupled plasma-mass spectrometry (MC-ICP-MS) to confirm the CRM’s within- and between-bottle homogeneity, and the results showed a 87Sr/86Sr ratio of 0.710227 ± 0.000019 (2SD, n = 18). The Sr isotopic compositions were intercompared using thermal ionization mass spectrometry (TIMS), which showed good agreement with values obtained at NIES. Subsequently, a consistent 87Sr/86Sr ratio was observed between two dissolution (hotplate vs. high-pressure bomb) and Sr separation (Sr spec resin vs. cation exchange resin) methods. To validate and reproduce the accuracy of our analytical methods, the Sr isotopic compositions of secondary reference materials, JB-1b and JA-2, were also measured. Our results showed that NIES CRM No. 28 is appropriate for the quality control of Sr isotope measurements of particulate matter analyses for environmental and geochemical studies

Simultaneous speciation of arsenic, selenium, antimony and tellurium species in waters and soil extracts by capillary electrophoresis and UV detection

7 pages, 5 figures, 3 tables.Capillary electrophoresis with indirect UV detection was used to determine simultaneously arsenic, selenium, antimony and tellurium compounds. The separation was achieved in a fused silica capillary filled with an electrolyte solution containing sodium chromate and an electroosmotic flow modifier, trimethyltetradecylammonium hydroxide (TTAOH). The effect of the TTAOH concentration and electrolyte solution pH on the electrophoretic mobility of the species was studied. The best simultaneous separation of these species was achieved with 0.5 mM TTAOH and an electrolyte pH of 11.2 within 5 min. Detection limits range from 13 µg l–1 for SeVI to 509 µg l–1 for TeIV with electromigrative injection. The reproducibility was below 10% and linearity was verified in the 0–100 mg l–1 range for all species. Interferences by other inorganic ions were studied. This method was applied to the determination of metalloids in a spiked drinking water. Water extracts of industrial soils were analysed and results were compared with those of ICP-MS measurements.The authors thank ECOS (Comité Evaluation–Orientation de la Coopération Scientifique entre France, Chili, Mexique et Uruguay—Action C96E04) for its financial support.Peer reviewe