Simulating systematic errors in X-ray absorption spectroscopy experiments: Sample and beam effects

Curis, Emmanuel; Osán, János; Falkenberg, Gerald; Bénazeth, S.; Török, Szabina

doi:10.1016/j.sab.2005.04.003

Cited by 9 publications

(4 citation statements)

References 52 publications

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“…Solution samples (RQ in CH 2 Cl 2 , RQ in H 2 O + HCl, Me-RQ in H 2 O + HCl, RQ in H 2 O + H 2 O 2 , Me-RQ in H 2 O + H 2 O 2 , and RQ and hemine in HEPES buffer) spectra were recorded in fluorescence mode using a seven-element germanium detector. Potential spectrum distortion induced by self-absorption was estimated using the approach previously described using the LASE software, which was written by one of us, , based on the solid state sample spectra, and it was found to be negligible for such diluted solutions. Spectra were recorded using the same energy grid as above, with an acquisition time of 4 s in the edge region and from 4 to 8 s in the k -scale region; each sample was recorded at least three times.…”

Section: Methodsmentioning

confidence: 99%

Statistical Methodology for the Detection of Small Changes in Distances by EXAFS: Application to the Antimalarial Ruthenoquine

et al. 2012

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Antimalarial compounds ruthenoquine and methylruthenoquine were studied by X-ray absorption spectroscopy both in solid state and in solution, in normal (aqueous or CH(2)Cl(2) solutions) and oxidative (aqueous solution with H(2)O(2), either equimolar or in large excess) conditions, to detect small changes in the coordination sphere of the ruthenium atom. Since changes in the EXAFS spectra of these compounds are quite subtle, a complete procedure was developed to assess the different sources of uncertainties in fitted structural parameters, including the use of multivariate statistic methods for simultaneous comparison of edge energy correction ΔE(0) and distances, which can take into account the very strong correlation between these two parameters. Factors limiting the precision of distance determination depend on the recording mode. In transmission mode, the main source of uncertainty is the data reduction process, whereas in fluorescence mode, experimental noise is the main source of variability in the fitted parameters. However, it was shown that the effects of data reduction are systematic and almost identical for all compounds; hence, they can be ignored when comparing distances. Consequently, for both fluorescence and transmission recorded spectra, experimental noise is the limiting factor for distance comparisons, which leads to the use of statistical methods for comparing distances. Univariate methods, focusing on the distance only, are shown to be less powerful in detecting changes in distances than bivariate methods making a simultaneous comparison of ΔE(0) and distances. This bivariate comparison can be done either by using the Hotelling's T(2) test or by using a graphical comparison of Monte Carlo simulation results. We have shown that using these methods allows for the detection of very subtle changes in distances. When applied to ruthenoquine compounds, it suggests that the implication of the nonbinding doublet of the aminoquine nitrogen in either protonation or methylation enhances the tilt of the two cyclopentadienyls. It also suggests that ruthenoquine and methylruthenoquine are, at least partially, oxidized in the presence of H(2)O(2), with a small decrease in the Ru-C bond length and increase in the edge energy.

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Section: Methodsmentioning

confidence: 99%

Statistical Methodology for the Detection of Small Changes in Distances by EXAFS: Application to the Antimalarial Ruthenoquine

et al. 2012

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“…207,208 The parameters given in Table 3 need specic consideration during simulation. 209,210 Thus, criteria for simulation of EXAFS spectrum [210][211][212] can provide precise bond-length 160,161 and coordination number of shells. 213 Fig.…”

Section: Exafsmentioning

confidence: 99%

Synchrotron radiation based X-ray techniques for analysis of cathodes in Li rechargeable batteries

et al. 2022

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“…In this study, we used a fairly simple technique that does not need elaborate calculations but solves the problem of the superimposing elemental spectral lines with a Bayesian deconvolution [29][30][31]. The net intensity of the spectral lines was then normalized with a Compton signal, whose intensity and shape are proportional to the atomic number [32] of the element considered and of the density and composition of the material analyzed.…”

Section: Introductionmentioning

confidence: 99%

Smart Determination of Gold Content in PCBs of Waste Mobile Phones by Coupling of XRF and AAS Techniques

et al. 2021

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Quantitative determination of most economic valuable metals in waste is the first fundamental operation of evaluating the feasibility of recycling processes. Field-portable X-ray fluorescence spectrometers (FPXRFs) represent a more practical, efficient, and economic tool in determining the elemental composition of samples with respect to conventional analytical techniques, such as atomic absorption spectrometry (AAS) and inductively coupled plasma emission spectrometry (ICP). In this paper, quick and smart determination of gold content in printed circuit boards (PCBs) of waste mobile phones was studied. The aim of the research was to combine the practicality of FPXRFs with the reliability of quantitative spectrometry analysis and evaluate the error between the two techniques. Several samples (33) of PCBs were ground to a size below 0.5 mm, and then, the powders were analyzed by FPXRFs at different acquisition times with five replications for each sample. The same analyzed samples then underwent chemical attack to determine the quantitative gold content by AAS. The obtained results were associated with FPXRFs response with the purpose of realizing a calibration curve (100–1000 mg/kg Au). The curve was validated for accuracy and precision by other PCBs waste samples; the control samples were added as standards to obtain a more reliable calibration curve. The curve was evaluated with RPD classification, regression linear, and Bolt–Altman analysis.

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Simulating systematic errors in X-ray absorption spectroscopy experiments: Sample and beam effects

Cited by 9 publications

References 52 publications

Statistical Methodology for the Detection of Small Changes in Distances by EXAFS: Application to the Antimalarial Ruthenoquine

Statistical Methodology for the Detection of Small Changes in Distances by EXAFS: Application to the Antimalarial Ruthenoquine

Synchrotron radiation based X-ray techniques for analysis of cathodes in Li rechargeable batteries

Smart Determination of Gold Content in PCBs of Waste Mobile Phones by Coupling of XRF and AAS Techniques

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