Preparation of calibrating standards for x‐ray fluorescence spectrometry of trace metals in plastics

Nakano, Kazuhiko; Nakamura, Toshihiro

doi:10.1002/xrs.675

Cited by 32 publications

(17 citation statements)

References 17 publications

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“…In our experience, applying pXRF to block samples can introduce its own issues which must also be considered by the analyst. These include, (a) ensuring proper degree of impregnation quality (e.g., length of time and setting during curation), which can be affected by the porosity of sediments and soils, especially in regard to clay‐rich samples which commonly demand the need to use a vacuum for proper impregnation (Courty et al, , p. 58), (b) measuring the chemical composition of the resin, which can include trace amounts of V, Cr, Co, Na, Ni, Ge, and Sb (Mentzer, ; Nakano & Nakamura, ), (c) understanding that there is an inability to determine the presence of inclusions or voids directly beneath the sampling area, and (d) controlling for the potential effect of differences between sampled areas that have large inclusions versus small (e.g., CaCO 3 nodules which would have strong Ca absorption which may affect the ability to interpolate nearby measurements). By following proper impregnation and curation protocols (see Goldberg & Macphail, , pp.…”

Section: Methodsmentioning

confidence: 99%

Elemental mapping of micromorphological block samples using portable X‐ray fluorescence spectrometry (pXRF): Integrating a geochemical line of evidence

Holcomb

Karkanas

2019

Geoarchaeology

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Archaeological soil and sediment micromorphology represent the most efficient way to obtain microcontextual information at archaeological sites. Because of the generally qualitative (descriptive) nature of micromorphology, one difficulty with the method is establishing vertical and lateral continuity of the observed layers or features. Through an Exploratory Spatial Data Analysis approach, we demonstrate that portable X‐ray fluorescence (pXRF) elemental mapping of resin‐impregnated micromorphological block samples provides a complementary geoarchaeological approach for gathering valuable chemical information at the mesoscale. Specifically, we integrate these data with micromorphological analyses to aid our interpretation of the formation of a complex Archaic (seventh century) ritual ash midden (eschara) from the site of Kalapodi, in Greece. We demonstrate that pXRF elemental mapping provides a rapid and cost‐effective approach to generate a geochemical line of evidence during micromorphological analyses, and can help tease apart and interpret complex formation processes, such as those found in anthropogenic deposits.

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Section: Methodsmentioning

confidence: 99%

Elemental mapping of micromorphological block samples using portable X‐ray fluorescence spectrometry (pXRF): Integrating a geochemical line of evidence

Holcomb

Karkanas

2019

Geoarchaeology

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“…For example, plastic (polyester) discs of certified reference materials (CRMs; JSAC 0611, 0612, 0613, 0614, and 0615) for the XRF determination of hazardous metal issued by the Japan Society for Analytical Chemistry contain some heavy metals . The analytes had the following analytical depths: 2 mm for Cr Kα (5.41 keV), 8 mm for Pb Lα (10.55 keV), and 40 mm for Cd Kα (23.17 keV).…”

Section: Thicknessmentioning

confidence: 99%

“…To avoid variations in fluorescent X‐ray intensities, Nakano et al . polished the surfaces of polyester discs in a milling machine to a thickness of 4.0 ± 0.1 mm and then further smoothed the surfaces by buffing …”

Section: Thicknessmentioning

confidence: 99%

Approaches to solid sample preparation based on analytical depth for reliable X‐ray fluorescence analysis

Ichikawa

Nakamura

2016

X-Ray Spectrometry

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In this paper, we discuss approaches to prepare solid samples for X-ray fluorescence spectrometry (XRF). Although XRF can be used to analyze major and minor elements in various solid samples including powders and grains without dissolution techniques, to obtain reliable XRF results, the prepared sample must meet certain criteria related to homogeneity, particle size, flatness, and thickness. The conditions are defined by the analytical depth of fluorescent X-rays from analytes, and the analytical depth can be estimated from the X-ray absorption related to the energy of each X-ray and the composition and density of the sample. For example, when the sample flatness and particle size are less than the analytical depth and the sample possesses homogeneity within a depth less than the analytical depth, the XRF results are representative of the entire sample. Furthermore, an appropriate sample thickness that is larger than the analytical depth or constant can prevent changes in fluorescent X-ray intensity with variations in sample thickness. To obtain accurate and reproducible measurements, inhomogeneous solid samples must be pulverized, homogenized, and prepared as loose powder, powder pellets, or glass beads. This paper explains the approaches used to prepare solid samples for XRF analysis based on the analytical depths of fluorescent X-rays.

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“…Others have investigated more empirical methods using a complete set of standards [2]. For a comparison of different XRF methods and their relation to atomic spectroscopy see Nakano and Nakamura [3].…”

Section: Introductionmentioning

confidence: 99%

F-7 Minimal Use of Standards for Quantifying Trace Elements in Plastics

Elam¹,

Scruggs²,

Shen³

et al. 2007

Powder Diffr.

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The minimum requirements for standards when quantifying trace elements in plastics by X-ray fluorescence (XRF) have been investigated. The fundamental parameters method, backed up by one or more standards, is used to translate XRF intensities into quantitative information about trace element concentrations. The method includes accounting for variations in sample thickness using scattered radiation. Of course, the method works best if the standards contain certified values of all of the trace elements of interest in a matrix identical to the unknown. However, we have had reasonable success using only a single element from a plastic standard as a calibrant. The presence of uncertified and uncalibrated elements in both the standards and the unknowns can also have a significant affect on the results, depending on how such elements are treated in the fundamental parameters method. We have also investigated using standards based on a different matrix than the unknown, such as polyvinyl chloride standards for analyzing various other plastic resins and water-based standards for analysis of trace elements in oil. Standard deviations are typically 10% to 15% relative when all elements are calibrated from a standard, and up to 20% when minimum use is made of standards.

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Preparation of calibrating standards for x‐ray fluorescence spectrometry of trace metals in plastics

Cited by 32 publications

References 17 publications

Elemental mapping of micromorphological block samples using portable X‐ray fluorescence spectrometry (pXRF): Integrating a geochemical line of evidence

Elemental mapping of micromorphological block samples using portable X‐ray fluorescence spectrometry (pXRF): Integrating a geochemical line of evidence

Approaches to solid sample preparation based on analytical depth for reliable X‐ray fluorescence analysis

F-7 Minimal Use of Standards for Quantifying Trace Elements in Plastics

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