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•Tutorial review addressed to beginners or more experienced analysts.•Theoretical background of effects caused by organic matrices on ICP techniques.•Spatial distribution of carbon ...species and analytes in plasma.•Carbon spectroscopic and non-spectroscopic interferences in ICP.
Due to their outstanding analytical performances, inductively coupled plasma optical emission spectrometry (ICP-OES) and mass spectrometry (ICP-MS) are widely used for multi-elemental measurements and also for isotopic characterization in the case of ICP-MS. While most studies are carried out in aqueous matrices, applications involving organic/hydro-organic matrices become increasingly widespread. This kind of matrices is introduced in ICP based instruments when classical “matrix removal” approaches such as acid digestion or extraction procedures cannot be implemented. Due to the physico-chemical properties of organic/hydro-organic matrices and their associated effects on instrumentation and analytical performances, their introduction into ICP sources is particularly challenging and has become a full topic. In this framework, numerous theoretical and phenomenological studies of these effects have been performed in the past, mainly by ICP-OES, while recent literature is more focused on applications and associated instrumental developments. This tutorial review, divided in two parts, explores the rich literature related to the introduction of organic/hydro-organic matrices in ICP-OES and ICP-MS. The present Part I, provides theoretical considerations in connection with the physico-chemical properties of organic/hydro-organic matrices, in order to better understand the induced phenomena. This focal point is divided in four chapters highlighting: (i) the impact of organic/hydro-organic matrices from aerosol generation to atomization/excitation/ionization processes; (ii) the production of carbon molecular constituents and their spatial distribution in the plasma with respect to analytes repartition; (iii) the subsequent modifications of plasma fundamental properties; and (iv) the resulting spectroscopic and non spectroscopic interferences. This first part of this tutorial review is addressed either to beginners or to more experienced scientists who are interested in the analysis of organic/hydro-organic matrices by ICP sources and would like to consider the theoretical background of effects induced by such matrices.
The second part of this tutorial review will be dedicated to more practical consideration on instrumentation, such as adapted introductions devices, as well as instrumental and operating parameters optimization. The analytical strategies for elemental quantification in such matrices will also be addressed.
The 236U/238U isotope ratio is a widely used tracer, which provides information on source identification for safeguard purposes, nuclear forensic studies and environmental monitoring. This paper ...describes an original approach to determine 236U/238U ratios, below 10−8, in environmental samples by combination of ICP-MS/MS for 236U/238U ratio and multiple collector ICPMS measurements for 235U/238U and 234U/235U isotope ratios.
Since the hydride form of UO+ (UOH+) is less prone to occur than UH+, we were focused on the oxidised forms of uranium in order to reduce hydride based-interferences in ICP-MS/MS. Then, in-cell ion-molecule reactions with O2 and CO2 were assessed to detect the uranium isotopes in mass-shift mode (Q1: U+ → Q2: UO+). The performances in terms of UO+ sensitivity and minimisation of hydride form of UO+ were evaluated using five different desolvating systems. The best conditions, using an Apex Ω or an Aridus system, produced uranium oxide hydride rate (235U16O1H+/235U16O+) of about 10−7 with O2 in the collision cell.
The method was validated through measurements of two certified IRMM standards with 236U/238U isotope ratio of 1.245 × 10−7 and 1.052 × 10−8, giving results in agreement with certified reference values. The relative standard deviations on seven independent measurements for each standard were respectively of 1.5% and 6.2%. Finally, environmental samples corresponding to sediments from the radioactive contamination plume emitted by the Fukushima Daiichi Nuclear Power Plant accident were analysed after a well-established uranium chemical separation procedure. 236U/238U atomic ratios between 1.5 × 10−8 and 7 × 10−9 were obtained with a level accuracy lower than 20%.
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•The ICP-MS/MS associated to a desolvating system reduces UOH+/UO+ down to 4.10−7.•O2 and CO2 show similar reaction profiles for U in the cell.•Precise uranium isotope ratios in sediments by combination of ICP-MS/MS and MC-ICP-MS.•Measurements of 236U/238U down to 10−8 in sediments for Fukushima area.•Precision obtained is the better ever achieved for 236U/238U ratios below 10−8.
The objective of this study is to determine for the first time the zinc (Zn) isotopic composition of different soil horizons, parent rocks, litter, and plants from a single pristine watershed.
Three ...soil profiles from Nsimi–Zoétélé site (South Cameroon, Africa) have been investigated. The δ
66Zn (δ
66Zn
=
(
66Zn/
64Zn)
sample
/
(
66Zn/
64Zn)
JMC 3–0749L)
−
1
⁎ 10
3) measured in the soils and rocks range from −
0.05 to 0.64‰. In a typical hillslope soil profile developed in situ from a granitic parent rock, we observe two important and systematic trends: i) a weathering regime in the saprolite horizon that involves strong Zn depletion, with no or slight fractionation compared to the fresh igneous rock, and ii) a shallower weathering regime with significant depletion in heavy Zn isotopes in the most superficial soil horizons. In contrast, the soil profile of the swamp zone does not exhibit isotopic fractionation between the soil and the parent rock.
Six plants and two litter samples were analyzed for their Zn isotopic compositions. δ
66Zn varied from 0.75 to −
0.91‰ among all samples. Plant roots and shoots are generally enriched in heavy isotopes (δ
66Zn of +
0.42 to +
0.76‰) relative to the litter layer (0.12 to 0.25‰) and most superficial soils. Similar to the controlled plant growth study of Weiss et al. Weiss, D.J., Mason, T.F.D., Zhao, F.J., Kirk, G.J.D., Coles, B.J. and Horstwood, M.S.A. (2005) Isotopic discrimination of zinc in higher plants. New Phytologist 165, 703-710., negative δ
66Zn values were obtained for tree leaves (the most aerial part of the tree). Based on biomass data for the tropical forest, vegetation is on average enriched in light isotopes compared to the litter and the superficial soil horizons which are the nutrients reservoirs.
Due to the age of these soils and the complexity of pedogenetic processes, it is difficult to explain the isotopic composition of the soils at present. However, the transformation of the saprolite horizon into a ferruginous horizon is associated with an enrichment in light Zn isotopes. This observation may be due to the adsorption of Zn onto clays surfaces. The uptake of Zn by roots in the soils leads to an enrichment in heavy isotopes. Once the Zn is in the xylem, it will be transported within the plant. During this transport, both diffusion and active uptake of heavy isotopes by cells out of the xylem favour the mobility of light isotopes to the most aerial parts of the plants.
The difference in Zn isotopic composition between the deep horizons and the superficial horizons of soils suggests that Zn isotopes can be used to discriminate the source of Zn and other metals leaving the catchment by river water.
Soil temperature and gas (CO
2
concentration and flux) have been investigated at Merapi volcano (Indonesia) during two inter-eruptive periods (2002 and 2007). Precise imaging of the summit crater and ...the spatial pattern of diffuse degassing along a gas traverse on the southern slope are interpreted in terms of summit structure and major caldera organization. The summit area is characterized by decreasing CO
2
concentrations with distance from the 1932 crater rim, down to atmospheric levels at the base of the terminal cone. Similar patterns are measured on any transect down the slopes of the cone. The spatial distribution of soil gas anomalies suggests that soil degassing is controlled by structures identified as concentric historical caldera rims (1932, 1872, and 1768), which have undergone severe hydrothermal self-sealing processes that dramatically lower the permeability and porosity of soils. Temperature and CO
2
flux measurements in soils near the dome display heterogeneous distributions which are consistent with a fracture network identified by previous geophysical studies. These data support the idea that the summit is made of isolated and mobile blocks, whose boundaries are either sealed by depositional processes or used as pathways for significant soil degassing. Within this context, self-sealing both prevents long-distance soil degassing and controls heat and volatile transfers near the dome. A rough estimate of the CO
2
output through soils near the dome is 200–230 t day
−1
, i.e. 50% of the estimated total gas output from the volcano summit during these quiescent periods. On Merapi’s southern slope, a 2,500 m long CO
2
traverse shows low-amplitude anomalies that fit well with a recently observed electromagnetic anomaly, consistent with a faulted structure related to an ancient avalanche caldera rim. Sub-surface soil permeability is the key parameter that controls the transfer of heat and volatiles within the volcano, allowing its major tectonic architecture to be revealed by soil gas and soil temperature surveys.
A new method for the direct determination of the 237Np/238U ratio in irradiated UO2 pellets by multicollection inductively coupled plasma mass spectrometry (MC-ICPMS) is proposed. This less time ...consuming method allows the determination of ratios down to 10 µmol·mol-1 using ion counter for the measurement of 237Np and Faraday cup for 238U. This method was validated by analyzing samples measurable by both quadrupole ICPMS and MC-ICPMS. For 237Np/238U included between 10 and 100 µmol·mol-1, expanded uncertainties by MC-ICPMS were varying respectively between 2.75 % and 0.81 % for the new method, at least twice lower than the uncertainties determined by Q-ICPMS.
The $^{236}$U/$^{238}$U isotope ratio is a widely used tracer, which provides information on source identification forsafeguard purposes, nuclear forensic studies and environmental monitoring. This ...paper describes an originalapproach to determine $^{236}$U/$^{238}$U ratios, below 10$^{−8}$, in environmental samples by combination of ICP-MS/MS for $^{236}$U/$^{238}$U ratio and multiple collector ICPMS measurements for $^{235}$U/$^{238}$U and $^{234}$U/$^{235}$U isotope ratios.Since the hydride form of U$^+$ (UOH$^+$) is less prone to occur than UH$^+$, we were focused on the oxidisedforms of uranium in order to reduce hydride based-interferences in ICP-MS/MS. Then, in-cell ion-moleculereactions with O$_2$ and CO$_2$ were assessed to detect the uranium isotopes in mass-shift mode (Q1: U$^+$ → Q2:UO$^+$). The performances in terms of UO$^+$ sensitivity and minimisation of hydride form of UO$^+$ were evaluatedusing five different desolvating systems. The best conditions, using an Apex $\Omega$ or an Aridus system, produceduranium oxide hydride rate ($^{235}$U$^{16}$O1H$^+$/$^{235}$U$^{16}$O+) of about 10$^{-7}$ with O$^2$ in the collision cell.The method was validated through measurements of two certified IRMM standards with $^{236}$U/$^{238}$U isotoperatio of 1.245×10$^{17}$ and 1.052×10$^{-8}$, giving results in agreement with certified reference values. The relativestandard deviations on seven independent measurements for each standard were respectively of 1.5% and6.2%. Finally, environmental samples corresponding to sediments from the radioactive contamination plumeemitted by the Fukushima Daiichi Nuclear Power Plant accident were analysed after a well-established uraniumchemical separation procedure. $^{236}$U/$^{238}$U atomic ratios between 1.5×10$^{-8}$ and 7×10$^{-9}$ were obtained with a level accuracy lower than 20%.
This tutorial review is dedicated to the analysis of organic/hydro-organic matrices by ICP techniques. A state-of-the-art focusing on sample introduction, relevant operating parameters optimization ...and analytical strategies for elemental quantification is provided.
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•Practical considerations to perform analyses in organic/hydro-organic matrices.•Description, benefits and drawbacks of recent introduction devices.•Optimization to improve plasma tolerance towards organic/hydro-organic matrices.•Analytical strategies for elemental quantification in organic/hydro-organic matrices.
Inductively coupled plasma optical emission spectrometry (ICP-OES) and mass spectrometry (ICP-MS) are increasingly used to carry out analyses in organic/hydro-organic matrices. The introduction of such matrices into ICP sources is particularly challenging and can be the cause of numerous drawbacks. This tutorial review, divided in two parts, explores the rich literature related to the introduction of organic/hydro-organic matrices in ICP sources. Part I provided theoretical considerations associated with the physico-chemical properties of such matrices, in an attempt to understand the induced phenomena. Part II of this tutorial review is dedicated to more practical considerations on instrumentation, instrumental and operating parameters, as well as analytical strategies for elemental quantification in such matrices.
Two important issues are addressed in this part: the first concerns the instrumentation and optimization of instrumental and operating parameters, pointing out (i) the description, benefits and drawbacks of different kinds of nebulization and desolvation devices and the impact of more specific instrumental parameters such as the injector characteristics and the material used for the cone; and, (ii) the optimization of operating parameters, for both ICP-OES and ICP-MS. Even if it is at the margin of this tutorial review, Electrothermal Vaporization and Laser Ablation will also be shortly described. The second issue is devoted to the analytical strategies for elemental quantification in such matrices, with particular insight into the isotope dilution technique, particularly used in speciation analysis by ICP-coupled separation techniques.
The high-precision isotopic characterization of actinides and fission products in nuclear samples is fundamental for various applications such as the management of spent nuclear fuel or the ...validation of neutronic calculation codes. However multi-elemental isotope ratio measurements by mass spectrometric techniques are hampered by the presence of both spectral and non-spectral interferences as complex sample matrices are encountered in such topics, but also due to the lack of high precision mass spectrometers able to cover the entire mass spectrum. This work describes a new LC-MC-ICPMS approach allowing simultaneous high-precision and multi-elemental isotope ratio measurements of four fission products of interest for nuclear issues (Nd, Sm, Eu, Gd) within a single elution run. Variable motorized Faraday cup configurations were successively used during a specifically designed elution procedure in order to take into account the non-natural Nd, Sm, Eu, Gd isotopic compositions encountered in irradiated nuclear samples. This new method, involving the relevant isotopic reference standard injection timings for on-line mass bias corrections, was validated by the analysis of a simulated fission product fraction from a 235U-irradiated target. Reproducibilities better than 2‰ (k=2), comparable to those obtained by off-line measurements and the classic sample-standard bracketing mass bias correction approach, were obtained for all isotope ratios, except those involving isotopes with a transient signal peak apex lower than 100mV, for which the reproducibilities were comprised between 2‰ and 6‰.
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•New hyphenated method between LC and MC-ICPMS.•Multi-elemental isotopic measurements by cup configuration switch during LC elution.•High precision isotopic measurements in nuclear fuel samples.•Comparison of data treatment methods for transient signals.
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