scholarly journals A simple determination of whole-rock major- and trace-element composition for peridotite by micro-XRF spectrometer and ICP-MS using fused-glass bead

2020 ◽  
Vol 54 (2) ◽  
pp. 81-90
Author(s):  
Norikatsu Akizawa ◽  
Akira Ishikawa ◽  
Tetsu Kogiso
2020 ◽  
Vol 20 (3) ◽  
pp. 23-32
Author(s):  
S. S. Savinov ◽  
N. A. Riadchikova ◽  
T. M. Pikalova ◽  
A. I. Drobyshev

Hair is one of the promising non-invasive samples for monitoring the trace element composition of the human body. But it is necessary to take into account the individual and subpopulation characteristics of sample donors. Inthis work, we experimentally studied the features of the analysis of human hair samples for the determination of trace elements by arc atomic emission spectrometry using a dry residue after acid mineralization. Validation was carried out by comparative analysis by the method used, as well as by atomic emission spectrometry with inductively coupled plasma. It has been shown that the concentrations of Al, B, Ca, Cu, Fe, Mg, Mn, P, Pb, Zn in a set of 50samples from different donors obey the lognormal law, and therefore, the geometric mean (or median) is preferable as mean value. The content of Ca and Mg is higher in the female hair, while the content of Pb is higher in the male hair. Theconcentrations of Fe, Mn, and Pb are slightly higher in the hair of smokers than in non-smokers, but this difference is not statistically significant (probably due to the small sample size). Although the concentrations of several elements (including Mg, Mn, and P) differ in the hair of donors living in different regions of Russia, we failed to establish asignificant difference of this factor. Positive correlations were found between the contents of some elements, in particular, Mg/Ca, Al/Fe, Al/P, Cu/Fe, Cu/P, Fe/P, weaker relationships were found for Al/Cu, Ca/Mn, Cu/Pb, Mn/P.


2020 ◽  
Vol 105 (6) ◽  
pp. 820-832 ◽  
Author(s):  
Aleksandr S. Stepanov ◽  
Leonid V. Danyushevsky ◽  
Ross R. Large ◽  
Indrani Mukherjee ◽  
Irina A. Zhukova

Abstract Pyrite is a common mineral in sedimentary rocks and is the major host for many chalcophile trace elements utilized as important tracers of the evolution of the ancient hydrosphere. Measurement of trace element composition of pyrite in sedimentary rocks is challenging due to fine-grain size and intergrowth with silicate matrix and other sulfide minerals. In this contribution, we describe a method for calculation of trace element composition of sedimentary pyrite from time-resolved LA-ICP-MS data. The method involves an analysis of both pyrite and pyrite-free sediment matrix, segmentation of LA-ICP-MS spectra, normalization to total, regression analysis of dependencies between the elements, and calculation of normalized composition of the mineral. Sulfur is chosen as an explanatory variable, relative to which all regressions are calculated. The S content value used for calculation of element concentrations from the regressions is calculated from the total, eliminating the need for independent constraints. The algorithm allows efficient measurement of concentrations of multiple chalcophile trace elements in pyrite in a wide range of samples, including quantification of detection limits and uncertainties while excluding operator bias. The data suggest that the main sources of uncertainties in pyrite composition are sample heterogeneity and counting statistics for elements of low abundance. The analysis of regression data of time-resolved LA-ICP-MS measurements could provide new insights into the geochemistry of the sedimentary rocks and minerals. It allows quantification of ratios of elements that do not have reference material available (such as Hg) and provides estimates on the content of non-sulfidic Fe in the silicate matrix. Regression analysis of the mixed LA-ICP-MS signal could be a powerful technique for deconvolution of phase compositions in complex multicomponent samples.


2012 ◽  
Vol 9 (8) ◽  
pp. 10615-10644 ◽  
Author(s):  
L. Jonkers ◽  
L. J. de Nooijer ◽  
G.-J. Reichart ◽  
R. Zahn ◽  
G.-J. A. Brummer

Abstract. Crust formation is a common phenomenon in planktonic foraminifera. Because of their different formation mechanism and hence composition, crusts affect the overall test composition and therefore complicate the use of crust-bearing foraminifera in paleoceanography. Such species are often used to estimate subsurface paleotemperatures and although the influence of the crust on the trace element/Ca ratio is recognised, it has not been systematically explored between and within tests. Here we use laser ablation ICP-MS to assess the variability in trace element composition of the crust of Neogloboquadrina dutertrei within individual chambers, as well as the effect of compositional heterogeneity of the crust on whole test chemistry. Compositionally, the outer crust differs from inner layer by lower Mg/Ca and Mn/Ca, but is indistinguishable in Sr/Ca. Crust thickness decreases towards the younger chambers and it may be entirely absent from the last chamber. In contrast to Mn/Ca and Sr/Ca, crustal Mg/Ca ratios show a tendency towards higher values on the younger chambers. These patterns in crust thickness and in crust Mg/Ca indicates that temperature is not the dominant factor controlling crust composition. Temperature estimates based on N. dutertrei, and presumably other crust-forming species too, are therefore biased towards too low values. Through comparison of modern and glacial tests we show that this bias is not constant and that changes in the crust thickness and/or in the Mg/Ca values can spuriously suggest temperature changes.


2015 ◽  
Vol 49 (3) ◽  
pp. 243-258 ◽  
Author(s):  
Akihiro Tamura ◽  
Norikatsu Akizawa ◽  
Ryo Otsuka ◽  
Kyoko Kanayama ◽  
Marie Python ◽  
...  

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