Energy Dispersive X-ray Fluorescence Spectrometry Research Articles

Synergistic effects of zinc and cadmium on phytoremediation potential of Christmas moss (Vesicularia montagnei)

The hyperaccumulation potential of zinc (Zn) and cadmium (Cd) and their synergistic effects were examined in relation to Christmas moss (Vesicularia montagnei (Bél) Broth., Hypnaceae), an aquatic and terrestrial moss, dosed with Cd (Cd1 and Cd2), Zn (Zn1 and Zn2) and combined Zn and Cd (Cd1Zn1 and Cd2Zn2). Zinc promoted plant growth and development, particularly in the highest Zn and combined Zn/Cd treatments (Zn2 and Cd2Zn2). The Zn treatment resulted in substantial moss chlorophyll content and highest percentage relative growth rate in biomass value (0.23 mg L−1 and 106.8%, respectively); however, the Cd2Zn2 treatment achieved maximal production of chlorophyll a and total chlorophyll (0.29 and 0.51 mg L−1, respectively) due to synergistic effects. These findings suggest that Christmas moss is a highly metal-tolerant and adaptable bryophyte species. Zinc was essential for reducing the detrimental effects of Cd while simultaneously promoting moss growth and biomass development. Furthermore, Christmas moss exhibited hyperaccumulation potential for Cd and Zn in the Cd2Zn2 and Zn alone treatments, as evidenced by highest Cd and Zn values in gametophores (1002 and 18,596 mg per colony volume, respectively). Using energy dispersive X-ray fluorescence (EDXRF) spectrometry, atomic percentages of element concentrations in moss gametophores in the Zn2, Cd2 and combined Zn/Cd treatments were generally in the order: K > Ca > P > Zn > Cd. When comparing the atomic percentages of Zn and Cd in gametophores, it is likely that the higher atomic percentage of Zn was because this element is essential for plant growth and development.

Elemental profiling of agricultural soil in Hoshiarpur utilizing analytical techniques.

Our study aimed to assess the soil quality in Punjab's Hoshiarpur district through a meticulous analysis of nutrient and elemental composition. Using a variety of analytical techniques, including Neutron Activation Analysis (NAA), external Particle-induced Gamma-ray Emission (PIGE) an Ion beam analysis Technique, and energy-dispersive X-ray fluorescence (ED-XRF), we delved into soil characterization for 22 agricultural soil samples in the Punjab region. Within the NAA framework, utilizing the Pneumatic Carrier Facility and the self-serve facility at Dhruva reactor in Mumbai, a brief 1-min irradiation procedure identified pivotal elements-Na, Mg, V, Al, Mn, and K. Conversely, an extended neutron irradiation process of approximately 4h within the self-serve facility enabled the estimation of nearly 12 elements, including Rare Earth Elements (REEs), Transition elements, and other significant elements. The external PIGE technique quantified low Z elements (Na, Mg, Al, and Si), contributing to our analytical arsenal. Rigorously validating both NAA and PIGE methodologies, we compared results meticulously against established geological standard reference materials-specifically USGS RGM-1 and USGS AGV-1.Instrumental in elemental analysis, ED-XRF spectroscopy fortified our investigative endeavors by quick assessment of ten crucial elements. The elemental analysis revealed notable accumulations of Mn and Zn in the soil, surpassing the suggested permissible limits, whereas Co, Cr, and Pb were found to be within the recommended thresholds set by WHO/UNEP. Beyond elemental profiling, our study extended to estimate the accumulation levels of various elements utilizing ecological risk factors such as Contamination Factor, Potential Ecological Risk Index, Pollution Load Index, and Geoaccumulation Factor. Our findings highlighted significant accumulation of REEs including La, Sm and Yb.. This evaluation sheds new light on the interplay between soil composition and environmental health, emphasizing the need for advanced accessible agricultural technologies to prevent and forecast contaminant discharge in arable soil. This commitment aligns with our broader goal of advancing sustainable practices in soil management.

Comparison of Quantitative and Qualitative EDXRF Analysis for Provenance Study of Archaeological Ceramics.

The most common scientific analysis of archaeological ceramics aims to determine the raw material source and/or production technology. Scientists and archaeologists widely use XRF-based techniques as a tool in a provenance study. After conducting XRF analysis, the results are often analyzed using multivariate analysis in addition to interpretation and conclusions. Various multivariate techniques have already been applied in archaeological ceramics provenance studies to reveal different raw material sources, identify imported pieces, or determine different production recipes. This study aims to evaluate the results of multivariate analysis in the provenance study of ceramics that belong to three cultures that settled in the same area during various prehistoric periods. Portable energy-dispersive X-ray fluorescence spectrometry (pEDXRF) was used to determine the elemental composition of the ceramic material. The ceramic material was prepared in two different ways. The ceramic body material was ground into powder, homogenized, and then pressed into tablets. After that, the same fragments are polished in suitable places. Quantitative and qualitative analyses were performed on the tablets and polished pieces. The results were subjected to both unsupervised and supervised multivariate analysis. Based on the results, it was concluded that qualitative analysis of the well-prepared shards' surface using EDXRF spectrometry could be utilized in provenance studies, even when the ceramic assemblages were made of similar raw materials.

Profile of mineral nutrients and proteins in soybean seeds (Glycine max (L.) Merrill): Insights from 95 varieties cultivated in Brazil

Soybean (Glycine max (L.) Merrill) stands out as a major source of protein meal for human and animal nutrition. Nevertheless, the increase in soybean yield has been accompanied by a reduction in protein content over the last decades. In this study, we determined the profile of mineral nutrients and total protein in 95 soybean varieties broadly cultivated in Brazil, the world’s largest soybean producer and exporter, to identify a possible association between seed mineral and protein content. Energy-dispersive X-ray fluorescence spectroscopy (EDXRF) was employed to determine the concentration of macro, i.e., potassium (K), phosphorus (P), sulphur (S), calcium (Ca), and micronutrients, i.e., iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu). The protein content of soybean seeds was evaluated using the Dumas method. The correlation and clustering between nutrients and proteins were determined using both univariate and multivariate non-parametric tests. Both protein and nutrient concentrations were not homogeneous across soybean seed varieties. It was also revealed that the higher the seed protein content, the higher the S, Mn, and Zn concentrations, whereas the opposite trend was observed for K and P. These results indicate an intricate association between S, Zn, Mn, and total protein content in soybean seeds.

Assessment of marine and urban-industrial environmental impact on stone acting as the base of a quaternary bronze sculpture

This work investigates the influence of a marine and urban-industrial environment on the deterioration of a funerary memorial in Getxo (Basque Country, Spain). The sculpture and artificial stone materials as well as their degradation products were characterised via a multi-analytical approach. An in situ characterisation of the bronze statue and its artificial limestone base was carried out with portable Energy Dispersive X-Ray Fluorescence (ED-XRF) and Raman spectrometers. In addition, several samples of white crusts as well as metal runoff crusts and biological patina were collected and some of them were prepared as cross-sections. High Resolution Micro-X-ray fluorescence and micro-Raman spectroscopy were used as non-destructive methods to detect original and degradation compounds. The test of soluble salts was also carried out on the samples and ion chromatography was employed in the laboratory. Exclusively calcite salt-efflorescences were found at the monument side with ED-XRF and Raman spectroscopy. While their morphology was compact at unsheltered sites, they showed a lamellar structure at sheltered locations, whose increased volume strongly influences the destruction of the memorial. The spectroscopic characterization of metal runoff showed that its excessive occurrence on the memorial surface was due to the dissolution of the copper-alloy caused by chemical reactivity with the surrounding acidic atmosphere. The formation of brochantite Cu4(SO4)(OH)6, posnjakite Cu4(SO4)(OH)6·(H2O), langite Cu4(SO4)(OH)6·2(H2O), or malachite Cu2(CO3)(OH)2 was favored exclusively in metal runoff crusts at unsheltered locations. However, much thinner crusts collected at sheltered sites showed a different composition, with copper species such as moolooite (Cu(C2O4)·nH2O) and atacamite Cu2Cl(OH)3. The soluble salt extraction showed a variable concentration of soluble ions depending on the area where the samples come from. The sample from north west sheltered location showed the highest content of sulfate, nitrate and chloride compounds. In addition, the concentration of fluoride and nitrate reflects the impact of contamination of surrounding industries.

Anatomy of the Painting: The Study of the Serbian Orthodox Icon from the Turn of the Seventeenth to the Eighteenth Century

The paper presents the results of the multi-analytical study of the painting on a panel from the icon collection of the Gallery of Matica srpska museum in Novi Sad, Serbia. It is part of the research aiming to set the methodology for the museum’s database on artistic materials and techniques present in the collection. Computer tomography (CT) scanning was used to understand the structure of the wooden panel support. Ultraviolet (UV) and infrared (IC) imaging, as well as visible (VIS) macro photography, were used to study the paint layer, both the original part and restoration treatments, as well as the coat of varnish. Energy dispersive X-ray fluorescence (EDXRF) and Fourier-transform infrared (FTIR) spectroscopy revealed the pigments, binders, and metal leaf, defining the artistic technique. Optical microscopy (OM) and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) were used to disclose the stratigraphy and composition of layers in the artwork. The multi-analytical approach confirmed that protein-based binder, gilding, silver leaf, and traditional pigments were used. The data gathered from this research are important for studying the artistic materials and techniques in icon production and defining the methodology setting for the museum collection’s databases as the reference material.

Colouring mechanism and firing technology of white porcelain from the Sui Dynasty (581–618) from the Xiangzhou kiln, Anyang, China

The Xiangzhou kiln was one of the first significant kilns in China to fire white porcelain and as well as the earliest one to adopt the technique of Make-up clay. It plays a very important role in the history of Chinese ceramics. Here we utilize ten pieces of Sui (581–618) white porcelain from the Xiangzhou kiln as the research objects. The chemical composition, micro-morphology, firing temperature, firing atmosphere, micro-area composition and other characteristics of white porcelain glaze were tested by energy dispersive X-ray fluorescence spectroscopy (EDXRF), laser Raman spectroscopy (LRS), optical microscope (OM), thermal dilatometer (TD), focused ion beam scanning electron microscope combined with X-ray energy spectrometer (SEM-EDS), X-ray photoelectron spectroscopy (XPS) and spectrophotometer (UV–Vis–NIR). Finally, the firing technology and colouring mechanism of the Xiangzhou white porcelain are revealed. Our study demonstrates that the relatively high content of Fe2O3 and TiO2 in the white porcelain glaze of the Xiangzhou kiln results in a milky white glaze with a slight greenish tinge. The high content of CaO and K2O in the glaze and the almost entirely glass phase of glaze layer lead to the fine grain, good transparency and gloss. Most of the white porcelain of the Xiangzhou kiln is fired at high temperature under reducing atmosphere. The Xiangzhou kiln white porcelain glaze belongs to the crystalline glaze, glaze disorderly distribution of some calcium feldspar precipitation crystals and a very small amount of quartz, calcite residual crystals, glaze bubbles are larger, the distribution of relatively dispersed. The overall colour effect of the Xiangzhou kiln white porcelain results from the combined action of the chemical colour of the body and glaze, along with structural colour.

Sieci neuronowe do mapowania archeologicznych artefaktów litowych

An analytical non-destructive strategy to chemically characterize lithic artefacts has been developed. Around 100 archaeological lithic materials found in Neolithic-Chalcolithic sites in the Mediterranean region of the Iberian Peninsula and nowadays stored in different museums of the Valencian Community (Spain), were studied. The materials belong to different typologies of rock (diabase, sillimanite, ophite and amphibolite) and were analysed employing portable energy dispersive X-ray fluorescence spectroscopy (pXRF) directly in the rock surface. The obtained data were processed through neural networks protocol, specifically the so-called Kohonen networks or Self Organised Maps (SOM), to map the geologic samples. This self-organized topological feature maps are suitable to deal with multidimensional representations and map them in a two-dimensional space of neurons, following an unsupervised learning protocol. SOM is used to reduce multidimensional data onto lower-dimensional spaces and clustering procedures. As a result, SOM create spatially organized representations, which enhance the discovery of correlations between data. In this case the method has enabled the evaluation of elemental markers related to each rock type behaving as a fine hidden pattern detector and so understand the possible advantages and disadvantages of the analytical method employed to define provenance issues. The attribution suggested by statistics is mainly driven by the composition of rocks essential minerals which are linked to the different petrogenetic conditions. The results showed that in most of the cases the distribution and dispersion of the chemical profile depend of the kind of rock, and clearly suggest that a good way to identify stone tools raw material procurement is to look for elemental markers, being the prior step to create an approximation to ancient exchange networks and their evolution in a diachronic axis.

Innowacyjne podejście metodologiczne do badania starożytnej zaprawy hydroizolacyjnej cystern zamku Sagunto

In this work, we present the results of the chemical, mineralogical and colorimetric characterization of the waterproofing mortars from the ancient cisterns of the Sagunto Castle (Valencia, Spain). The fortress presents 2500 years of human occupation and, given the lack of natural water sources, collecting and storing rain water was mandatory ever since. Nowadays, several cisterns are found in the hill, and thus the application of analytical approaches can help in characterizing each layer within the cultural phases of the Castle’s history (Iberian, Punic, Roman, Islamic, Medieval, Modern or Contemporary). Mineralogical analyses were carried out employing X-ray diffractometry and mid-infrared attenuated total reflection spectroscopy, and, on the other hand, the portable energy dispersive X-ray fluorescence spectroscopy was employed to obtain the concentrations of major and minor chemical elements. Colour features of the samples were identified by smartphone photo processing to observe possible relation between colour and waterproofing mortar compounds. Last, Raman spectroscopy was employed to analyze the different phases present in the samples. Multivariate statistics were employed to identify different waterproofing mortar layers and develop hypotheses concerning different construction phases and compare their manufacturing processes. Analytical results allowed to find common patterns among different cisterns and mortar layers, and colorimetric analyses showed good potential as an additional fast, cheap and non-destructive source of information for studying these types of samples.

Association between exposure to specific PM2.5 constituents and environment, lifestyle, and clinical parameters in patients with COPD

ABSTRACT This study investigated the correlation between the individual chemical constituents of particulate matter 2.5 μm (PM2.5) and respiratory parameters as well as the living environment and daily behaviors in patients with chronic obstructive pulmonary disease (COPD). Data were obtained from prospective COPD panel conducted in South Korea. Following collection via a microPEM, 18 metallic elements were determined using energy-dispersive X-ray fluorescence spectroscopy. All participants completed detailed questionnaires on living environments and lifestyle practices. Eighty-nine stable COPD patients (mean age 68.1 years; 94.4% male) were analyzed. Several constituents (titanium, aluminum, bromine, and silicone) were significantly associated with respiratory outcomes. Copper and manganese concentrations were significantly associated with the living environment. Increased ventilation time and air purifier operation were associated with lower concentrations of copper, silicone, barium, and titanium. These findings suggest varying relationships between PM2.5 constituents and clinical parameters in COPD patients, providing a basis for personalized interventions and future research.

The Iridescent Painting Palette of Michelino da Besozzo: First Results of Non-Invasive Diagnostic Analyses

This study concerns the characterization of the color palette of Michelino da Besozzo, one of the leading painters and illuminators of the Late Gothic period in Northern Italy. The artist’s relationship with the color blue was investigated by considering the recipe for lapis lazuli given by the artist to Giovanni Alcherio in Venice in 1410 and found in the medieval treatise of Jean Lebegue. The paper highlights this important evidence for the study of painting technique in the first half of the 15th century with an analytical and technical study of two paintings: The Mystic Marriage of Saint Catherine (Siena, Pinacoteca Nazionale, inv. 171) and The Madonna of the Rose Garden (Verona, Museo di Castelvecchio, inv. 173-1B359). These two case studies were approached through analyses carried out with non-invasive and portable techniques such as Energy Dispersive X-ray Fluorescence (ED-XRF) spectroscopy and Fiber Optics Reflectance Spectroscopy (FORS). The results show a color palette based on ultramarine, azurite, verdigris or copper resinate; earths, cinnabar or vermillion; and lead white, yellow and red ochre and lac. These preliminary results made it possible to clarify certain aspects of the artist’s style and his painting technique and identify common elements between the two works of art.

Mineral and particle-size chemometric classification using handheld near-infrared instruments for soil in Northeast Brazil

The characterization of soil variations crucial for agriculture is challenging due to soil having different mineral composition and particle-size distribution. Traditional methods are costly and time-consuming for large-sized areas. Spectroscopic techniques coupled with chemometrics are alternative ways to overcome these drawbacks. Miniaturized near-infrared (NIR) spectrophotometers provide fast, cost-effective spectra acquisition for assessing soil chemistry and distribution despite challenges like overlapped bands and reduced spectral range. This study presents a pattern recognition strategy to address these limitations, enhancing the use of handheld NIR instruments for soil analysis. The study analyzed 176 soil samples from 15 soil groups in the Northeast region of Brazil. First, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) and energy-dispersive X-ray fluorescence spectrometry (EDXRF) were employed to characterize the samples, providing complementary vibrational and elemental information, respectively. Common Dimension Analysis (ComDim) identified links between ATR-FTIR and EDXRF data, aiding soil characterization. The Common Components (CCs) from ComDim were used in Partitioning Around Medoids (PAM) clustering, resulting in five distinct classes based on their mineral composition. These classes showed significant differences in clay and sand contents. With the use of ComDim-PAM, samples were labeled for classification via Partial-least Squares-Discriminant Analysis (PLS-DA) and Support Vector Machine (SVM) using NIR spectra (spectral range: 908–1676 nm) from two handheld instruments (Hand 1 and Hand 2). The SVM models outperformed the PLS-DA models, especially by including variable selection for Hand 1, with test accuracy exceeding 90%. These findings highlight the method's advantages for fast and cost-effective assessment, classification, and soil mapping based on their mineral and particle-size distribution.

Application of handheld/portable spectroscopic tools to the identification, inner stratigraphy and mapping of archaeological metal artefacts

Field handheld/portable instrumentations, such as in-situ geochemical analyzers, have the potential to assist efficiently targeted geochemical archaeometry campaigns in detecting and quantifying specific elements. Non-destructive portable energy dispersive x-ray fluorescence and micro-destructive handheld laser-induced breakdown spectroscopy (LIBS) instrumentation were utilized to investigate the elemental composition, internal stratigraphy by depth profiling and microscale compositional mapping of five copper and two iron alloy artefacts collected from various ancient graves in the Minervino Murge area, Apulia, Italy. The primary elements identified by both techniques included Cu, Sn and Pb in copper alloys, and Fe with minor amounts of Cu and Pb in iron alloys. Furthermore, the elements Al, Ca, Si, Mg, Na and K, mostly originated from soil contamination, and the trace elements Sb, Ni and Zn were detected. The satisfactory performance of both techniques was assessed by their capacity to provide reproducible elemental composition data. Finally, the depth profile and mapping achieved by LIBS contributed to understanding the metal processing and history of the objects studied, so confirming both techniques to be robust analytical tools in outdoor archaeology and archaeometry campaigns.

Studies on the Authorship of Albumen Vintage Photographs: A Combined Experimental and Chemometric Approach.

The differences in albumen photographs from vintage photographic studios were identified by energy-dispersive X-ray fluorescence spectroscopy and Fourier transform infrared spectroscopy. The results inspired the concept of finding common features characteristic of a given photographic studio. The obtained measurement data (i.e., positions of vibrational bands for characteristic groups of albumen and the mass contents of chosen elements) were analyzed chemometrically by employing the Principal Component Analysis (PCA). The PCA technique allowed us to reduce the number of relevant experimental parameters characterizing the unique features of the photographic objects. The two major components were able to distinguish the photographic objects in terms of their authorship and the time to produce a photograph. The method developed was examined for a selected group of photographs consisting of albumen prints from three Polish photographic ateliers. To validate ED-XRF measurements and, consequently, the chemometric findings, reference albumen photo samples were designed and prepared. The empirical functional relationships between the content of photochemically reduced silver particles on the photographic paper and several physicochemical factors, including time of exposure to UV light, AgNO3 concentration in a fixed bath, and concentrations of other additives, were proposed. These results can be used for the prediction of the experimental conditions under which the investigated photographs were developed.

Fast, accessible and reliable method for elemental analysis of metals in solution by ED-XRF spectroscopy

The measurement of metals in solution is usually performed using inductive coupled plasma hyphenated techniques or atomic absorption. Although very sensitive and accurate, these analytical techniques are quite expensive and do not allow field measurements. The present work takes advantage of energy-dispersive X-ray fluorescence (ED-XRF) ease-of-use features to determine the concentration of rare earth elements (Y, Pr, Nd, Eu) and others (S, Fe, Ni, Cu, Zn) in aqueous solutions, after appropriate sample treatment. The approach turned out to be a reliable and very convenient procedure for field analysis. The simplicity, speed and reliability of the methodology used combined with the possibility of simultaneous analysis and low cost of the method can be advantageous in industrial context. The approach relies on the suspension of the target solutions in a cellulose matrix that is further converted into a pellet for direct analysis. Calibration curves obtained by regression analysis at 5% significance are shown for a variety of elements (S, Fe, Ni, Cu, Zn, Y, Pr, Nd, Eu) with correlation coefficients between 0.9555 and 0.9980. Higher coefficients of variance were obtained for the calibration of S and Pr due to low sensitivity and the overlapping with the L lines of Nd, respectively. The performed calibrations were not affected by the presence of other analytes in the matrix. Results obtained showed that it is possible to use the proposed methodology to accurately quantify d and f block metals in aqueous solutions by ED-XRF after sequestering the chemical content into a cellulose powder matrix and further processing into a pellet.Graphical

Compositional characterization of paint sample by neutron and charge particle activation analysis: validation by energy dispersive X-ray fluorescence spectrometry

The elemental composition of the paint was determined by non-destructive nuclear analytical techniques, namely neutron activation analysis (NAA), charge particle activation analysis (CPAA), and energy dispersive X-ray fluorescence (EDXRF). NAA was chosen as the primary method of analysis as there is no matrix effect, requirement of a small quantity of a sample, detection capability down to ppb level, and self-validation. Ba, Ca, and Cr are detected as the major constituents, whereas Co, Hf, Mn, Y, Sr, Sb, W, Zn and Zr were detected at trace levels in the paint sample by NAA. CPAA was also utilized for the analysis, and elements like Ca, Cr, Fe, Sr, Ti and Zr were detected in the sample. The validation of the analytical results obtained in NAA and CPAA was carried out by the EDXRF technique, in which, including Si, most of the transition and high Z elements like Ca, Cr, Fe, Sr, Zr and Ba were detected. Analysis of variance was carried out to establish the statistical indistinguishability and acceptability of the analytical results obtained by these three methods. This study showcases the capability of NAA and CPAA for routine compositional analysis of paint sample without the requirement of a matrix matched standard.

ZnS@ fluorenone derived multifunctional quantum dots for simultaneous recognition of bovine serum albumin (BSA) and copper ions (Cu2+) in aqueous blood and urine samples

An efficient synthesis of water-stable and fluorescent ZnS quantum dots has been executed beginning with its organic predecessor possessing fluorenone for sensing bovine serum albumin (BSA) among other proteins. Moreover, the organic predecessor of quantum dots has also been utilized for sensing of F- ions with binding constant of 1.8 × 104 M−1. Various spectroscopic techniques such as high-resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (PXRD), UV-visible (UV-vis), Fourier transform infrared (FTIR), thermogravimetric (TGA), Energy dispersive X-ray analysis (EDX), circular dichroism (CD) and Fluorescence (FL) spectroscopy have been utilized for the characterization of the developed quantum dots. The emission properties of quantum dots made them useful for the sensing of BSA and Cu2+ accompanied with secondary sensing of urea. The LODs value for BSA and Cu2+ were calculated as 213 and 211 nM, respectively. Demonstrating remarkable efficacy, these quantum dots have been successfully employed for the discernment of BSA in human blood and urine samples, achieving an outstanding recovery rate of up to 99.8%.

Influence of fluoride characteristics on tooth surface protection in an erosive condition: A multifaceted characterization approach.

To evaluate the effect of fluoride consistency and composition to protect enamel and dentin against the dental erosion. Bovine enamel and dentin specimens were treated with artificial saliva, neutral fluoride gel (NFG), acidulated phosphate fluoride gel (AFG), neutral fluoride foam (NFF), and acidulated phosphate fluoride foam. The samples were subjected to cycling. Micro energy-dispersive X-ray fluorescence spectrometry, surface roughness (Ra), contact angle (CA), and scanning electron microscopy (SEM) were performed. Composition, CA and Ra data were analyzed by ANOVA and multiple comparison test (p < 0.05). The dentin protected had a significantly higher mineral content than in the control. Eroded unprotected enamel had higher Ra values than normal surfaces. Fluoride treatments increased the Ra in dentin samples. AFG increased the CA in enamel. Fluoride foams increased CA in dentin with reduced mineral loss. SEM analysis found a deposited layer on enamel treated with AFG and remnants of deposits on dentin treated with NFG and NFF. Regardless of the form of application, fluoride provided protection against erosion, however with different levels. Applying the adequate fluoride form is relevant since the formulations have different effects on both enamel and dentin.

Combined use of principal component analysis/multiple linear regression analysis and artificial neural network to assess the impact of meteorological parameters on fluctuation of selected PM2.5-bound elements.

Based on the data of the State of Global Air (2020), air quality deterioration in Thailand has caused ~32,000 premature deaths, while the World Health Organization evaluated that air pollutants can decrease the life expectancy in the country by two years. PM2.5 was collected at three air quality observatory sites in Chiang-Mai, Bangkok, and Phuket, Thailand, from July 2020 to June 2021. The concentrations of 25 elements (Na, Mg, Al, Si, S, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Br, Sr, Ba, and Pb) were quantitatively characterised using energy-dispersive X-ray fluorescence spectrometry. Potential adverse health impacts of some element exposures from inhaling PM2.5 were estimated by employing the hazard quotient and excess lifetime cancer risk. Higher cancer risks were detected in PM2.5 samples collected at the sampling site in Bangkok, indicating that vehicle exhaust adversely impacts human health. Principal component analysis suggests that traffic emissions, crustal inputs coupled with maritime aerosols, and construction dust were the three main potential sources of PM2.5. Artificial neural networks underlined agricultural waste burning and relative humidity as two major factors controlling the air quality of Thailand.

Critical evaluation of energy dispersive X-ray fluorescence spectrometry for multielemental analysis of coffee samples: Sample preparation, quantification and chemometric approaches

In the present contribution, a critical evaluation of the use of EDXRF (Energy dispersive X-ray fluorescence spectrometry) for elemental composition determination (K, Ca, Mn, Fe, Cu, Zn, Sr and Rb) of coffee samples is presented. Firstly, several sample treatment procedures (pressed pellets and loose powder) and quantification strategies (fundamental parameters and empirical calibration) were evaluated.In addition to quality and nutritional purposes, information of elemental content in coffee samples can be also useful for coffee traceability and provenance studies. In view of that, a comparison of different tools such as explorative principal component analysis (PCA) and classification by partial least square regression (PLS-DA) were also tested as discriminating tools of different types of coffee samples (i.e., pure, instant and coffee with additives). Chemometric analysis was performed using coffee elemental concentrations determined by the developed EDXRF method and, for the first time, using raw EDXRF spectra obtained, without the need of a fitting and quantification procedure.