Portable X-ray Fluorescence Analysis Research Articles

Characteristics of foundries and alloy composition of modern and contemporary Korean artistic bronze

This study investigated the changes in foundries and production techniques of modern and contemporary Korean artistic bronze constructions from the 1910s to the 2000s. To determine the characteristics of foundries and changes in alloy composition based on era, interviews with key sculptors and foundry technicians, analysis of archival materials related to casting, and nondestructive X-ray fluorescence analysis of 92 bronze sculptures by Manlin Choi, were conducted. This study found that foundries for artistic bronze underwent technical and organizational changes from the 1910s to the 2000s. Modern casting techniques and foreign technologies have been introduced since the late 1960s that have resulted in various production methods. The portable X-ray fluorescence analysis of Manlin Choi’s 92 bronze sculptures revealed distinct differences in alloy composition depending on the foundry, findings that have also been supported by records (contracts, receipts, payment confirmations). This study systematically organizes the changes in foundries and production techniques of modern and contemporary Korean artistic bronze, identifying correlations between alloy composition and foundries, and is expected to provide important data for the future conservation and scientific authentication of artistic bronze.

Field-portable X-ray fluorescence analyzer for chemical characterization of carbonate-bearing base metal tailings: case study from Namib Pb-Zn Mine, Namibia

Reprocessing of historic gold tailings is a common activity in South Africa, while base metal tailings offer similar reprocessing potential. The historic base metal tailings of the Namib Pb-Zn mine (Erongo Region, Namibia) still contain valuable resources of Pb and Zn in carbonate-rich matter. Micro-analysis of primary ore minerals identifies some galena as argentiferous and sphalerite as the principal host of Cd. This study demonstrates that knowledge of primary ore mineralogy helps to reveal the hosts of valuable commodities (Ag, Cd) and that field-portable X-ray fluorescence tools allow precise and accurate determinations of major and minor elements like Zn and Cd in such carbonate-rich material. Although there are limitations to directly determine the contents of certain element (i.e., As, Sb, In), linear correlations allow prediction of the likely abundance of these elements. Providing that the inter-mineral and inter-element relations are understood and there is consistency in sampling and analytical methodology, portable X-ray fluorescence analysis is an effective method to evaluate the chemical characteristics of base metal tailings for a range of major and trace elements.

Suitability of XRF for Routine Analysis of Multi-Elemental Composition: A Multi-Standard Verification.

This study investigated the suitability of X-ray fluorescence (XRF) analysis for routine multi-elemental composition analysis, checking its analytical capabilities by measuring a wide array of certified reference materials of soil and plant origin. A portable XRF analyzer was used to evaluate 32 soil and 12 plant standard materials, using both the Soil and Geochem mode, with sequential beams, allowing the detection of a wide range of elements. Recovery rates were calculated by comparing XRF measurements with certified values, and their correlations were verified through the Spearman coefficient. The results demonstrated the reliability of XRF measurements for soil samples, with a large number of elements showing a good or very good recovery and strong correlations with certified values. For plant samples, XRF largely overestimated the certified values, but the strong statistically significant correlations for almost all tested elements allowed us to correct this systematic bias, using the reported median value for dividing the value obtained via XRF. The Geochem mode emerged as more reliable for a larger number of elements. It was concluded that XRF may be a suitable alternative to ICP-MS in routine multi-elemental composition analysis.

Seasonal aspects of macro, trace, and ultra trace element changes in soils with different anthropogenic loads

Studying seasonal changes in the concentrations of macro, trace and ultra trace elements in soil samples is important for solving a number of environmental problems in mountainous regions. An innovative technical approach, using a portable X-ray fluorescenceanalyzer, was used to detect changes in the concentrations of certain chemical elements in soil samples from different regions of Armenia during the four seasons. Based on the established Clark concentration for chemical elements, a pollution index was calculated. Regardless of the season, the significance of the pollution index for trace elements is greater than the value of the other elements of the group. Moderate direct and inverse correlations between macro and trace elements, as well as between trace and ultra trace elements were dominant throughout the experimental cycle in all soil samples. The results obtained are of practical importance for the development of mountain soils for agricultural use and can be useful for the preparation of geochemical maps of the distribution of macro, trace, and ultra trace elements to adjust the geochemical background of heavy metals in the soils of Armenia.

Chains of Currency: Manilla Money Bracelets, Early Modern Africa and the Ties That Bind

Manilla money bracelets emerged during the early modern period (ca. fifteenth century AD) as a form of currency between western Europe and West Africa, and continued to circulate until the early twentieth century. While there has been little formal scholarship on manillas, narratives abound: some histories cast the bracelets as the blood money of the transatlantic slave trade; others highlight them as the copper source used to make the Benin Bronzes; and still others uphold the manilla as a symbolically important West African cultural object in and of itself. This study begins with a history of the manilla, from its rapid proliferation to its eventual obsolescence. The term “metastasizing symbol” is proposed to describe objects like the manilla, whose propagation is underwritten by unsustainable systems of cultural difference, and thereby contains within itself the seeds for the object’s transition to disuse. The authors also describe a portable X-ray fluorescence (pXRF) analysis of nine manilla bracelets from the Yale University Art Gallery (YUAG). When compared to manilla composition data from previous studies and projected into PCA space, the nine YUAG manillas appear most similar to specimens produced in England during the mid-nineteenth century and traded extensively in British West Africa throughout the colonial period. KEYWORDS: Manilla Money Bracelets; pXRF; Transatlantic Slave Trade; Europe; West Africa; Early Modern Period; European Imperialism; Provenance

Research on the application of Bagging W-KNN algorithm in alloy steel identification with PXRF analyzer

In response to the inadequate alloy steel identification capability and intelligent recognition of domestic portable X-ray fluorescence analyzers, as well as the impact of existing classification algorithms due to factors such as imbalanced data distribution, this paper proposes the Bagging W-KNN intelligent identification algorithm for alloy steel grade. This method is based on the K-nearest neighbor classification algorithm, employs the Chi-Square statistical method, Bagging ensemble algorithm, introduces the Gini index from the decision tree classification algorithm, and utilizes the Gaussian function probability estimation method. Comparative experiments with four typical algorithms—Decision Tree, KNN, SVM, and Naive Bayes—demonstrate that the proposed algorithm achieves accuracy, precision, recall, and F1 values of 97.01%, 97.30%, 96.69%, and 96.18% respectively, significantly outperforming the other four algorithms and improving prediction accuracy.

Water Content and Pb Concentrations in the Bottom Sediments Of The Gdansk Deep (South-Eastern Baltic Sea) According to the Portable X-Ray Fluorescence Analyzer Olympus Vanta C

Water Content and Pb Concentrations in the Bottom Sediments Of The Gdansk Deep (South-Eastern Baltic Sea) According to the Portable X-Ray Fluorescence Analyzer Olympus Vanta C

A novel calibration method for portable X-ray fluorescence analysis of printed circuit boards.

Printed circuit boards (PCBs) are the most complex and valuable component of electronic devices, but only 34% of them are recycled in an environmentally sound manner. Improving the recycling rate and efficiency requires a fast, reliable and uncostly analytical method. Although the X-ray fluorescence (XRF) shows high potential, it is often unreliable. In this study, we propose a novel XRF methodology for the elemental analysis of PCBs, using the certified reference material (CRM) to decrease uncertainty and enhance accuracy. The results show significant improvement in robustness and accuracy of portable XRF(pXRF) analyses for elements Cu, Pb, Ni, As and Au, with a relative average inaccuracy of approximately 5% compared to referenced values. The methodology validation carried out by comparing pXRF and inductively coupled plasma mass spectroscopy analyses of personal computer motherboard samples shows no statistically significant difference for elements Cu, Cr and Ag. The study shows that the calibration of pXRF by CRMs enables the necessary analysis of PCBs in an efficient and reliable manner and could be also be applied to different types of PCBs and other electronic components, batteries or contaminated soil samples.

Classification of geologic materials used in the Sukhothai Historical Park of Thailand using a portable X-ray fluorescence analyzer and petrographic analysis

The Sukhothai Historical Park, designated as a world heritage site in Thailand, encompasses the remnants of the Sukhothai Kingdom and serves as a valuable locus for geological and geoarchaeological investigations. Situated in the Sukhothai province, the region is characterized by diverse lithologies, including slate, phyllite, and laterite, as well as red bricks (synthetic materials), utilized in the construction of various ancient structures. Petrographic analysis using polarized light microscopy reveals the phyllites as the primary dimension stones, exhibiting foliated and mylonitic textures with small quartz augen. A portable X-ray fluorescence analyzer was employed for geochemical analysis and the analysis of major oxides and trace elements. The resulting data facilitated the classification of protoliths and comparison with rocks from an abandoned quarry near Saritphong Dam in the western part of the historical park. Notably, phyllites utilized in several prominent structures within the park; Wat Saphan Hin, Wat Pa Daeng 2, Wat Thap Sakae, Wat Chetuphon, Wat Sri Chum, and Wat Mangkorn Temples, exhibited similar characteristics to those in the Wat Khao Noi old quarry, as confirmed by Rubidium (Rb) and Strontium (Sr) values. The SiO2/Al2O3 and FeO/K2O ratios were pivotal in identifying the protoliths of the studied phyllites as shales. In summary, the primary dimension stones for Sukhothai Historical Park originated from the western mountain within the park, with laterites sourced from foothill areas. The presence of quartz pebbles in red bricks suggests local sediment utilization, and quartz additions were employed to enhance structural strength. This comprehensive geoarchaeological study sheds light on the geological composition of the Sukhothai Historical Park, providing valuable insights into the selection and utilization of construction materials in this historically significant site.

A multi-proxy geochemical and micromorphological study of the use of space and stratigraphy of a Viking-age house in Ribe, Denmark

High-definition approaches are currently revolutionizing our understanding of the archaeology of urban archives. Multi-proxy studies at a high spatial resolution offer especially an opportunity to capture their high data potential. Here we present a study of complex floor layers from an occupation phase dating to c. AD 790–830 uncovered in the Viking-age emporium Ribe, Denmark (c. AD 700–900). In order to better understand stratigraphy and the use of indoor space, mapping for soil geochemistry (portable X-ray fluorescence analysis, pXRF) on a high-resolution grid (0.25 × 0.25 m, n = 1059), was combined with targeted sampling for soil micromorphology and artefact distributions. The results show that the studied occupation phase was composed of several short-lived floor phases belonging to two consecutive houses that had been sampled in conjunction, and which exhibited a complex stratigraphy. The older house phase had a primarily domestic function, where ten functional areas could be defined, and are interpreted as designated spaces for food preparation, storage, sitting or sleeping, and weaving. A younger house phase contained a metal workshop in addition to domestic functions. Methodologically, a number of new, potentially anthropogenic, elements of archaeological interest, such as arsenic, manganese and sulfur, were identified that may contribute to interpretations, while the multi-proxy approach elucidates the refined scale at which we can understand a complex stratigraphic sequence and the integrity of its units. This study shows how the various aspects of Viking-age urban life (craft production, domestic life) were integrated, and sheds light on the dynamics of urban occupation.

Rapid X-ray fluorescence analysis as a modern alternative to traditional spectral methods in geochemical prospecting

The purpose of the study is to present the research results of the capabilities of modern portable rapid X-ray fluorescence analyzers when solving problems of geological and geochemical prospecting. On example of the applied SciAps X200 analyzer, the metrological indicators for the analysis results by portable instruments have been studied. The accuracy assessment results of analytical studies according to state standard reference samples are shown. Reproducibility of the analysis results is calculated on the basis of samples from promising gold sites of the Bodaibo synclinorium. The method is proved to be of high precision, and measurement errors in many cases are many times lower than the permissible certified values. The reproducibility is shown as 0,5–20 % depending on the element, which in most cases is significantly lower than the methodology permits. The results of interlaboratory comparative tests confirming the comparability of the analytical results of stationary and portable X-ray fluorescence analyzers are presented. For a number of significant elements, the authors have substantiated the lack of need to refine the results of the field rapid X-ray fluorescence analysis using labor-intensive and expensive methods with acid decomposition - atomic emission and atomic absorption spectroscopy. It has been proved that introduction of portable express equipment into geological prospecting works will make it possible to conduct real-time “on site” analytical studies.

Portable XRF applied to regional bedrock mapping in Quebec, Canada

Whole-rock geochemistry yields better geological maps of the bedrock, since it allows, for example, visually similar lithologies to be distinguished. However, conventional laboratory geochemistry is not available in the field during a mapping campaign. Portable X-ray fluorescence (pXRF) analyzers can produce fit-for-purpose data rapidly, and constitute a useful complement to conventional geochemistry in a bedrock mapping project. The pXRF data can be employed (i) while still in the field, to orient the mapping campaign; (ii) to prepare a preliminary geological map back in the office; and (iii) to interpolate between conventional whole-rock analyses on the final map. The latter application requires a matrix-matched secondary calibration of the pXRF data to improve its accuracy. Attention must also be given to precision issues, as well as potential instrument drift and analytical interferences.This paper summarizes recent efforts to systematically integrate quantitative pXRF data in government mapping projects within the Province of Quebec (Canada). We first demonstrate how an Olympus Vanta series M pXRF analyzer was commissioned and calibrated. We then show how the pXRF data was systematically acquired and utilized during a 1:50,000 to 1:20,000 mapping campaign in a Precambrian greenstone belt setting (Abitibi Subprovince). Before the mapping began in 2021, volcanic rocks in the study area were supposed to consist of only two mafic tholeiitic formations, called Obatogamau and Bruneau. Integrating pXRF into this project meant that while still in the field and immediately afterwards during preparation of the preliminary map: (1) a marker horizon representing the top of the Obatogamau Formation was chemically identified and then traced laterally; (2) the felsic Waconichi Formation was recognized despite the high metamorphic grade and also traced laterally just above the marker horizon; (3) the Bruneau Formation was shown to be much more continuous than previously known and to have Mg-tholeiites at its base, like in the type locality; (4) the Blondeau Formation was shown to occur above the Bruneau Formation. Within the volumetrically dominant Obatogamau Formation, Fe-tholeiites were also distinguished from visually similar Mg-tholeiites, which allowed these subunits to be traced while still in the field, leading to a more detailed map. Later, after the conventional laboratory chemistry had been received, the final geological map was prepared, but it was very similar to the preliminary map, confirming the satisfactory performance of the pXRF method for this application. However, we do note some issues and limitations even with the latest generation of analyzers.

First discovery of charcoal-based prehistoric cave art in Dordogne

Archaeologists have long been puzzled by the exact age of Paleolithic cave art in Europe especially in the Franco-Cantabrian region with hundreds of decorated caves because the creation of this parietal art (paintings, drawings and engravings) is closely tied to the appearance of first modern humans in Europe and their ways of life. The Dordogne region, one of the richest regions in terms of Paleolithic cave art in the world with more than 200 cave sites, is currently known to provide figures of cave art solely made with mineral coloring matters that cannot be dated directly. Using in-situ non-invasive Raman spectroscopy combined with portable X-ray fluorescence analysis as well as visible and infrared imaging of the decor of the Font-de-Gaume cave, we show the presence of a large number of charcoal-based Paleolithic figures besides others made of iron and manganese oxides in the main galleries for the first time. The creation periods of the cave art at Font-de-Gaume are mainly attributed to the Magdalenian period and probably more complicated constituted of at least two creation phases than commonly established as shown by the direct or partial superimposition of carbon-based and iron- and/or manganese-based figures. Our new results contribute to a better understanding of the organisation of the ornamentation and thus of the imaginary language of our Prehistoric ancestors. The discovery opens new research possibilities for re-reading of the complex panels and absolute radiocarbon dating.

Purposefully purple: understanding the technological transition from late Medieval green to purple glazed Humber wares

The rise of purple glazed pottery in fifteenth-century England represented a major change in the character of domestic material culture. These wares typically evolved from the orange bodied, green glazed pottery of the later medieval period and were produced by a number of centres. This paper examines the technological advancements made by potters working at West Cowick (East Yorkshire) as they navigated the transition from green to purple glazed Humber wares. While it well known that recipes and firing regimes can be manipulated by potters to modify and enhance their colour pallet, the change exacted by West Cowick’s potters has been overlooked, dismissed by archaeologists as the result of over-firing. Through a range of analytical techniques (thin section petrology, scanning electron microscopy microstructural analysis, chemical characterisation of fabric and glaze by portable X-ray fluorescence analysis and scanning electron microscope–energy dispersive spectroscopy), we reconstruct the glazing practices employed by these potters, revealing innovative artisans, skilled in controlling glaze recipes and firing regimes, and able to effect major intentional changes in their product.

Predicting rock hardness using Gaussian weighted moving average filter on borehole data and machine learning

A comprehensive understanding of the hardness of ore being handled and processed in a mining operation can significantly improve operational efficiencies. This is feasible by providing valuable data to support decision-making through the mining value chain (drilling, blasting, loading, comminution). This study presents the results of a machine learning (ML) approach for rock hardness prediction using rock’s geophysical and geochemical features. Core samples from several mine sites were logged using a multi-sensor core logging (MSCL) system. Measurements include ultrasonic P- and S-wave velocity, elemental concentration via portable X-Ray fluorescence analyzers (pXRF), and Leeb rebound hardness, measured every 30 cm along 564 m of core samples. K-Means and PCA were used for better interpretation of the data. Supervised ML models (XGBoost and Random Forest) were utilized to predict rock hardness using the elemental concentrations and ultrasonic velocities as predictors. Since the data was collected automatically with predefined intervals, some of the measurement points were near fractures or veins. The Gaussian weighted moving average (WMA) was used to smooth out variations in geochemistry or hardness caused by local features that do not reflect the overall rock characteristics. This approach is effective for building ML models to become less susceptible to local rock features. It was concluded that the rock hardness could be effectively predicted using only geochemistry, and the process of collecting P- and S-wave velocity for hardness prediction can be skipped.

Obsidian in the Valley of Volcanoes, Peru

The Andagua Valley in the Department of Arequipa of southern Peru has only recently seen systematic archaeological investigations, revealing ancient agricultural communities that, despite apparent geographic isolation, were integrated economically with the wider Andean world. Portable x-ray fluorescence analysis of 137 obsidian artifacts recovered from sites in the lower Andagua Valley identifies the transfer of obsidian from Peru’s three largest sources, with > 90% of the analyzed artifacts coming from the Alca-1 source northwest of the valley. In addition to Alca-1 obsidian, small amounts of obsidian from the distant sources of Chivay and Quispisisa appeared in distinct contexts associated with local pre-Inka occupations, corresponding with the Middle Horizon and Late Intermediate Periods (600 – 1000 and 1000 – 1400 Common Era). Obsidian from the Alca-4 and Alca-5 sources, originating on the adjacent plateau, was also transported to Andagua during these periods, possibly continuing under Inka imperial expansion after 1400 CE.Because there is no archaeological evidence of either Wari or Tiwanaku states in the lower Andagua Valley, the probable mechanisms of obsidian transfer include direct or down-the-line exchange between plateau-based camelid pastoralists and valley farmers. Therefore, at least some long-distance obsidian transfers in southern Peru were carried out without direct oversight from Wari or Tiwanaku, though these transfers may have been facilitated by region-scale economic integration during the Middle Horizon and Late Intermediate Period. Tracing the distribution of obsidian in the Andagua Valley highlights both intra-valley and inter-zonal relationships between the Valley of the Volcanoes and specific areas of the high-elevation Andean plateau while illuminating dynamic economic and social connections along the central Andes in the pre-Hispanic past.

Utilising Portable Laser-Induced Breakdown Spectroscopy for Quantitative Inorganic Water Testing

At present, the majority of water testing is carried out in the laboratory, and portable field methods for the quantification of elements in natural waters remain to be established. In contrast, portable instruments like portable X-ray fluorescence (pXRF) analysis and portable laser-induced breakdown spectroscopy (pLIBS) have become routine analytical methods for the quantification of elements in solids. This study aims to show that pLIBS can also be used for chemical compositional measurements of natural waters. Bottled mineral waters were selected as sample materials. A surface-enhanced liquid-to-solid conversion technique was used to improve the detection limits and circumvent the physical limitations in liquid analysis. The results show that low to medium mineralised waters can be analysed quantitatively for their ions using the documented method. For more highly concentrated samples, typically above an electrical conductivity (EC) of 1000 µS/cm, further adjustment is required in the form of self-absorption correction. However, water with a conductivity up to this limit can be analysed for the main cations (Li+, Na+, Mg2+, K+, Ca2+, and Sr2+) as well as the main anions (SO42− and Cl−) using the documented method. This study demonstrates that there is significant potential for developing field-based pLIBS as a tool for quantitative water analysis.

The toxicological assessment of hazardous elements (Pb, Cd and Hg) in low-cost jewelry for adults from Chinese E-commerce platforms: In situ analysis by portable X-ray fluorescence measurement

This article focusses on the environmental implications of low-cost jewelry for adults from Chinese e-commerce platforms ((n = 8) with heavy metal impurities (Pb, Cd and Hg) and their potential impact on human health and the environment. The study highlights the advantages of using portable X-ray fluorescence (pXRF) analysis for rapid, non-destructive, and in situ analysis of heavy metals in jewelry. The results reveal that all products (n = 106) contained heavy metals at varying levels, Hg being the most commonly detected heavy metal. The fact that 71% of the samples exceeded the EU limit for Pb and 51% exceeded the EU limit for Cd is alarming and highlights the need for stricter regulations and monitoring of the jewelry industry to mitigate the risks posed by heavy metals in the environment. The study emphasizes the importance of using pXRF analysis to identify heavy metals in jewelry and address the literature gap in environmental risk assessments of Pb, Cd, and Hg in low-cost jewelry for adults from China. In general, the findings call for urgent action to ensure the safety of consumers and prevent environmental pollution by strengthening regulations and monitoring the jewelry industry.

Evaluating the Application of Portable Handheld X-ray Fluorescence (XRF) Scanner for Determining Seafood Provenance: A Case Study on Penaeus monodon.

Seafood elemental profiling (SEP) is the quantification of a range of elements in seafood products and may serve in addressing questions of seafood provenance and quality. Traditional methods for analyzing soft tissue present several limitations for the industry-level use of SEP. Portable handheld X-ray fluorescence (pXRF) analysis is a promising alternative to conventional methods; however, its application for biological analysis has not been fully established. Intact giant tiger prawn (Penaeus monodon) abdomens were analyzed with a Vanta M series XRF portable analyzer following a novel soft tissue protocol. Exploratory statistics (principal component analysis, nonmetric multidimensional scaling, and canonical discriminant analysis), as well as random forest models, have been implemented with pXRF profiles, yielding 81% accuracy when assigning the geographical origin of P. monodon. The results of this study highlight that SEP via pXRF is a viable industry-level analysis, and its application will depend on improved instrument calibration to account for fluctuating wetness factors that are influenced by cooking, storage, and other pre- and post-harvest treatments.

Testing the suitability of portable X-Ray Fluorescence (pXRF) analysis of dried herbarium specimens to detect Ni hyperaccumulators in South Africa

Metal hyperaccumulators accumulate particular metals or metalloids in their leaves to concentrations hundreds or thousands of times greater than is normal for most plants. Globally, Ni is the most often hyperaccumulated metal, with 532 hyperaccumulator species documented to date. Hyperaccumulators have attracted much attention as potential candidates for green technologies, including phytoremediation and agromining. In South Africa, six serpentinite-associated plants in the genera Berkheya and Senecio hyperaccumulate Ni (to > 0.1% of leaf tissue dry weight). It is surprising that only six of about 70 Berkheya and 290 Senecio species native to South Africa hyperaccumulate Ni, given about ∼10–20% of taxa from each genus occur on serpentinite. While it is costly and time consuming to field collect and chemically analyze leaves of all species in these genera, a novel method (portable X-Ray Fluorescence or pXRF analysis of herbarium specimens) allows for rapid (100 s of specimens/day) and non-destructive measurement of Ni in dry herbarium specimens. We tested the accuracy of this approach on known Ni hyperaccumulators vouchered at two South African herbaria (C.E. Moss Herbarium (J) of the University of the Witwatersrand and A.P. Goossens Herbarium (PUC) from North-West University). While the absolute concentrations of Ni determined by ICP-MS and pXRF were not always directly in agreement, we had 100% success in confirming those that were known to hyperaccumulate Ni with those that did not. We propose pXRF as a cheap, effective, and efficient approach to rapidly screen herbarium specimens across South Africa to discover additional metal hyperaccumulators for much-needed remediation purposes.