Portable Energy Dispersive X-ray Fluorescence Research Articles

Graph clustering and portable X-Ray Fluorescence: An application for in situ, fast and preliminary classification of transport amphoras

In the last decade, numerous papers have been delivered on the potential of portable X-Ray Fluorescence (XRF) in archaeological ceramics. Additionally, new chemometric methods have been proposed to manage chemical dataset and facilitate the use of geochemical discrimination for provenance classification of ancient ceramics. In this contribute, the potential of portable Energy Dispersive X-Ray Fluorescence (ED-XRF) analysis and chemical data processing by Graph Clustering is evaluated for provenance classification of archaeological potteries, discussing possible merits and limits of the employed routine. A ceramic assemblage represented by seventy-three transport amphorae classified by typological analysis have been used as testing materials; spectra have been collected on samples simulating in situ analysis conditions (e.g. on fresh cut surfaces without any preparation) and Graph Clustering method has been applied in chemical data processing; comparison with classical Cluster Analysis (CA) and Principal Component Analysis (PCA) is also evaluated. The obtained results favor the use of Graph Clustering for a preliminary classification of ceramics, which can be chemically analyzed in easy, fast and non-destructive way. With a 75.35% of correct attribution, the study shows the suitability of portable ED-XRF in rapid screening of a large number of ceramic samples usually recovered in the framework of archaeological excavation. Misclassifications have been mostly verified for samples exhibiting a coarse-grained clay paste, suggesting that the method is particularly suitable for fine-grained ceramic materials.

Mercury Exposure Associated with Use of Skin Lightening Products in Jamaica.

Background.Skin bleaching is a major health concern among Jamaicans. A common ingredient in skin lightening products is mercury. Mercury is a toxic substance that can cause damage to the gastrointestinal tract, nervous system and kidneys.Objective.The objectives of this study were to use different analytical techniques to measure mercury concentrations in popular skin lightening products used in Jamaica and to assess individual levels of mercury exposure based on product usage.Methods.Sixty skin lightening products were purchased from different vendors across various locations in Jamaica. Each product was initially screened for mercury using a portable handheld energy dispersive X-ray fluorescence (XRF) analyzer. In addition, 25 out of 60 products were further measured using cold vapor atomic absorption spectroscopy (CVAAS). Questionnaires were distributed to users of skin lightening products to determine their usage patterns.Results.Six products had mercury concentrations above the United States Food and Drug Administration (FDA) allowable limit of 1 ppm, of which three products contained alarmingly high concentrations (i.e. > 400 ppm). The majority of products (57 out of 60) had mercury concentrations below 10 ppm. The mercury concentrations in skin lightening products ranged from 0.05 ppm to 17,547 ppm. In our sample, 51% of women and 49% of men used skin products more than once per day.Conclusions.On average, creams contained more mercury than lotions and soaps. Individuals who use skin lightening products in Jamaica may be at risk for high mercury exposure, as some popular products were found to have mercury concentrations above the allowable limit.Competing Interests.The authors declare no competing financial interests.

The use of pXRF for light element geochemical analysis: a review of hardware design limitations and an empirical investigation of air, vacuum, helium flush and detector window technologies

Light element data are required for robust and accurate lithogeochemical interpretations and are important components in the study of hydrothermal alteration and mineralization processes. In this contribution we review the latest available portable energy dispersive X-Ray Fluorescence (pXRF) technologies exclusively in the context of light element analysis, with focus on the acquisition of data for Na, Mg, Al and Si. We discuss pXRF hardware design limitations, quantify variables that attenuate X-ray energies through numerical modelling, including common pXRF configurations, and empirically investigate modern pXRF technologies used to mitigate X-ray attenuation and improve light element analysis. The void between the sample and detector is a key issue regarding the success of pXRF light element analysis. Dry-air (normal conditions), vacuum purge and helium flush systems are evaluated. Modelled data that use a nominal sample-detector void of 10 mm show that using helium in lieu of air improves X-ray transmission effectiveness from ≈2% to ≈99% for Na and ≈10% to ≈100% for Mg. Modelled detector window data show that using a graphene detector window in lieu of a traditional beryllium detector window improves X-ray transmission effectiveness for Na from ≈38% to ≈64% and ≈57% to ≈77% for Mg. Progressive X-ray transmission effectiveness equates to ≈63% Na and ≈76% Mg when using a helium-graphene pXRF configuration v. ≈1% for Na and ≈6% Mg when using a traditional in-air beryllium pXRF arrangement (i.e. without sample or X-ray entrance window media). Empirically determined improvements of the resolved signal are more modest than those of modelled X-ray transmission effectiveness data. Instrument noise, spectral overlaps and random counting errors are unavoidable and inherent with the limitations of modern detector technologies. However, the employment of helium with graphene detector window technology allows very precise data to be obtained at significantly shorter scan times (i.e. 20 s, instead of the traditional 60–180 s, i.e. 3–9 times faster): a scan time of 20 s can achieve a precision of ≈18% @ ≈0.4% Na and ≈8% @ ≈0.3% Mg for elemental interference-free samples. Precision will improve with increasing analyte concentration.

What shall we put in the grave? Archaeometric analyses of ceramics from a late Pre-Roman, Roman and Migration period cemetery in Malbork-Wielbark, northern Poland

AbstractThe necropolis at Malbork-Wielbark was excavated from 1927 to 1936 and 2008 to 2019. This burial ground is the eponymous site of the Wielbark culture. To date, over 2000 burials, both inhumation and cremation (pit and urn graves), have been recorded at this site, attesting to its continuous use from the Early Pre-Roman Iron Age (phase A1) to the early Migration Period (phase D1), with particular emphasis on the Roman Period. The cemetery site partially overlies and damages an earlier Iron Age settlement of the Pomeranian culture.Laboratory analyses were carried out on 113 pottery sherds. The series of samples chosen for analysis reflected, as far as was possible, all relative chronological phases and vessel shapes. The pottery was analysed using a step by step strategy built on the results of MGR-analysis (i. e. the classification of samples based on their matrix type) and on a macroscopic assessment of clastic material. In addition, an estimation of chemical composition by portable energy-dispersive X-ray fluorescence (pXRF) was available for each sample. After they had been classified, samples were selected for chemical analysis by wavelength-dispersive X-ray fluorescence (WD-XRF), estimation of physical ceramic properties (open porosity, water absorption and apparent density), Kilb-Hennike analysis (K-H analysis), thin-section studies using a polarising microscope, a study of surface phenomena by RTI (Reflectance Transformation Imaging), thermal analysis (TG-DTG-DTA), X-ray diffraction analysis and functional properties analysis (water permeability and thermal shock resistance), as well as experimental estimation of magnetic properties.The results of MGR-analysis carried out on ceramic samples taken from 113 potsherds revealed that all of the pottery was made from various non-calcareous clays with fine-grained iron compounds homogeneously distributed in the matrix. It was decided not to carry on determining/using MGR-groups, as nearly every sherd represents a different MGR-group. This means that these vessels were made during different production cycles. The differences in thermal behaviour between samples were attributed only to matrix-type groups. It can be concluded that 85 % of the total sherds were made from plastic raw materials of the same provenance, and that the same matrix-type groups occurred in all chronological phases. The percentage of vessels made of particular raw materials indicates a significant difference in the preferences of Pomeranian Culture potters and those of Pre-Roman Iron Age, Early Roman Period and those of the Late Roman Period, when one type of raw material disappears from use. This last period is also characterized by an increase in the number of vessels fired in a reducing atmosphere. Standardization is also evident in vessel-wall thickness, which falls within a narrow range of values, on the other hand combined with a large variety in grain sizes up to very large ones and with a wide range of open porosity values, which in turn points to a lack of care in the preparation of the ceramic body. Vessels that may have been non-local origin are noted in all chronological phases. Analysis of functional properties (water permeability and thermal shock resistance) revealed that the pottery deposited in graves included fully functional wares, such as cooking pots, as well as vessels intended solely as grave goods.More than a few samples evidence the use of a slow-rotating potter’s wheel, and it is also possible that a template was used for forming vessel rims. However, there are very few examples of truly technologically advanced vessels. The technology is generally tailored to the desired type or form of vessel.

Macro-classification of meteorites by portable energy dispersive X-ray fluorescence spectroscopy (pED-XRF), principal component analysis (PCA) and machine learning algorithms

The research on meteorites from hot and cold deserts is gaining advantages from the recent improvements of portable technologies such as X-ray fluorescence spectroscopy (XRF). The main advantages of portable instruments include the fast recognition of meteorites through their classification in macro-groups and discrimination from materials such as industrial slags, desert varnish covered rocks and iron oxides, named “meteor-wrongs”. In this study, 18 meteorite samples of different nature and origin were discriminated and preliminarily classified into characteristic macro-groups: iron meteorites, stony meteorites and meteor-wrongs, combining a portable energy dispersive XRF instrument (pED-XRF), principal component analysis (PCA) and some machine learning algorithms applied to the XRF spectra. The results showed that 100% accuracy in sample classification was obtained by applying the cubic support vector machine (CSVM), fine kernel nearest neighbor (FKNN), subspace discriminant-ensemble classifiers (SD-EC) and subspace discriminant KNN-EC (SKNN-EC) algorithms on standardized spectra.

Examination of the composition and mechanism of discoloration of the fugitive pigment copper resinate

Copper resinate was a green pigment used through the Renaissance when it was largely discontinued due to its tendency to discolor to brown over time. Historically, this pigment was made by grinding copper(II) acetate, or verdigris, in a tree resin rich in abietic acid. Commercial copper resinate and copper(II) abietate mixtures were analyzed by electrospray ionization mass spectrometry, infrared and visible spectroscopy. The pigment consists of mixed organic copper salts with bridged acetate (Ac) and abietate (Ab) ligands (i.e, [Cu2Ab4], [Cu2Ab3Ac], and [Cu2Ab2Ac2]) based upon sodiated ions detected in mass spectra. The lipophilic abietate groups allow the molecules to dissolve in the resin and oil binders for a transparent glaze free of pigment particles. A paddlewheel bridged-dimer structure of [Cu2Ab4] modeled by density functional theory has similar bond distances to copper(II) acetate. Experimental results suggest that copper(II) abietate lacks the axial water ligands found in copper(II) acetate. The green color of copper resinate originates from a combination of the blue typical for organic copper salts and the yellow of free abietate/abietic acid. Solutions of both verdigris and copper resinate quickly discolor to brown upon the addition of a dilute basic solution. Slow conversion of organic copper salts in the paint layer to brown copper(II) oxide, possibly enhanced by environmental conditions or cleaning with alkaline materials, may be an alternate discoloration mechanism in cultural artifacts. Copper detected by portable energy dispersive X-ray fluorescence (XRF) spectroscopy and scanning electron microscopy with energy dispersive X-ray (SEM-EDX) in discolored paint layers of an Italian Renaissance painting by Tintoretto is consistent with this artist’s established use of copper resinate.

A simple and sustainable portable triaxial energy dispersive X-ray fluorescence method for in situ multielemental analysis of mining water samples

In-situ monitoring of potentially toxic elements in mining water samples is of special relevance in order to evaluate the environmental impact of abandoned mining activities. However, it is difficult to develop suitable analytical methods for this purpose considering the complexity of mining water samples matrix as well as the limited sensibility of conventional filed portable X-ray fluorescence spectrometry systems (pXRF).In the present contribution, a simple, sustainable and reliable triaxial pXRF method (3pXRF) is proposed for multielemental analysis of mining water samples. In this method, several microliters of sample are deposited onto a commercial filter paper retainer and after drying, the loaded filter is directly analyzed in the field using a laboratory pXRF with orthogonal triaxial geometry (p3XRF). This geometry reduces the background of the measured spectra improving peak-background ratios in comparison with conventional pXRF systems.Using the best analytical conditions (sample deposition volume of 200 μL and 600 s as measurement time), limits of detections were in the low mg∙L−1 range and therefore suitable considering the expected high metal concentration in mining water samples. Acceptable accuracy and precision of the results was obtained in comparison with laboratory techniques such as inductively coupled plasma optical emission spectrometry and total reflection X-ray fluorescence spectrometry but with the possibility of in-situ measurements in the field. The developed method was applied to the analysis of different types of mine water samples (stream waters, drainage water tanks and mining lake waters) collected in the mining districts of Tinoca (Portugal) and Cartagena-La Unión (Spain).

Portable EDXRF and Principal Component Analysis for inorganic element determination and provenance of eye shadows

Nos dias de hoje, produtos cosméticos desempenham um importante papel na vida de quase todas as pessoas. Homens e mulheres dedicam muito tempo, recursos e esforços para cultivar a higiene pessoal e a melhor aparência possível ao longo de suas vidas. Um dos tipos de cosméticos mais utilizados é a sombra para os olhos. A fluorescência de raios X (XRF) é uma técnica bem estabelecida, conhecida por sua capacidade de identificar e quantificar espécies inorgânicas de maneira simples, rápida e não-destrutiva, no entanto, não é amplamente utilizada em análises de produtos cosméticos. A fim de se mostrar a potencialidade da técnica, fluorescência de raios X por dispersão em energia portátil foi empregada na quantificação de elementos inorgânicos em 40 sombras para os olhos brasileiras. Foi possível identificar e quantificar os elementos Cl, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn e Bi. Utilizando a análise de componentes principais, foi possível distinguir os diferentes fabricantes. A metodologia de fluorescência de raios X associada à análise de componentes principais provou ser uma ferramenta valiosa para a discriminação e caracterização de produtos cosméticos.

Archaeometric analysis of patinas of the outdoor copper statue Sant'Oronzo (Lecce, Italy) preparatory to the restoration

The Sant'Oronzo statue (Lecce, Southern Italy) consists of an internal wooden structure, completely covered with copper sheets, lying on a concrete base about 1.5 m high, which is placed on the top of a Roman column about 29 m high. Lecce may be classified as urban site since it is mainly influenced by vehicular traffic and it is not affected by intense industrial emissions.In the time schedule of the restoration, first of all, non-destructive analyses were planned. In particular, a portable energy dispersive X-ray fluorescence (ED-XRF) was used in order to map the composition of the patinas and to evaluate their degradation. Subsequently, a micro-sampling was performed both of the statue and the column. The collected samples were analysed by using Raman spectroscopy and X-Ray Diffraction in order to evaluate chemical composition.This paper summarizes the archaeometric results and the diagnostic information obtained before of the restoration, which are significant for the restorers’ subsequent work.

A new carbonate-specific quantification procedure for determining elemental concentrations from portable energy-dispersive X-ray fluorescence (PXRF) data

Portable energy-dispersive X-ray fluorescence (PXRF) analyzers are routinely used to generate large elemental datasets in sedimentary strata. These data provide the basis for assessing stratigraphic changes in geochemistry, bulk mineralogy, and paleo-redox conditions. The manufacturer provided procedure used to calculate elemental concentrations from PXRF photon counts that was developed for siliciclastic mudrocks. This quantification is, however, routinely applied to other sedimentary rocks, such as carbonates, which often have very different elemental concentrations and rock textures. The current study reports elemental concentration data from 57 limestone and dolomite rock samples measured by both PXRF and conventional geochemical analyses including inductively coupled plasma-mass spectrometry (ICP-MS), inductively coupled plasma - optical emission spectrometry (ICP-OES), and wavelength-dispersive X-ray fluorescence (WD-XRF). Carbonate samples were subdivided into two groups. The calibration set (N = 43) is used to establish a carbonate-specific PXRF quantification procedure, and to investigate the effects of different sample preparation techniques. The validation set (N = 14) is used to evaluate the applicability of both the newly developed carbonate-specific quantification procedure and the existing mudrock quantification procedure for the carbonate rock suite.PXRF measured photon counts in the calibration set exhibit strong positive linear correlations (R2 = 1–0.76) with the elemental concentrations independently measured from ICP-MS and/or ICP-OES, and WD-XRF. These linear relationships were used to calculate elemental concentrations in the validation set, which were then statistically compared with the measured elemental concentrations. Results of the carbonate-specific quantification procedure show that 13 elements (Mg, Al, Si, P, K, Ca, Ti, Mn, Fe, Rb, Sr, Y, and Zr) in the carbonate validation set are quantified with PXRF at the definitive data quality level. The mudrock-based quantification procedure, in contrast, quantified only 4 elements at the definite data quality level (Si, K, Ca, and Zr), suggesting that carbonate-specific calibration should be used to ensure higher data quality. The results from the sample preparation experiments exhibit different linear regressions for whole rock, loose powders, pressed powder pellets, and fused discs.The results of this study show that (i) PXRF can reliably identify and accurately quantify the concentrations of 13 common rock-forming elements in carbonate rocks; (ii) the carbonate-specific quantification procedure provides a higher level of data quality for carbonate rocks compared to the mudrock-based quantification; (iii) carbonate rock samples are inherently heterogeneous and thus require more intensive sample preparation and advanced statistical methods to account for this in the quantification procedure; and (iv) the matrix effect that results from different sample preparations must be accounted for in the quantification procedure.

Optimizing subsampling strategies for U/Th dating and geochemical proxies in carbonate speleothems

Since they provide the chronological frame on which paleoclimate and paleoenvironmental reconstructions are built, radiometric ages of carbonate speleothems, especially U/Th dating, are of fundamental importance to speleothem and paleoclimate sciences. Based on 17 aragonite-calcite speleothems from the Pont-de-Ratz Cave (S. France), we propose an integrated petrographical and geochemical approach for optimizing subsampling in speleothems. Portable energy-dispersive X-ray fluorescence was used as a fast and non-destructive in-situ trace-element screening of the speleothems. These geochemical results are combined with petrographical and mineralogical information to produce distribution maps showing the growth discontinuities and the identified primary and secondary (diagenetic) products on the speleothem slabs. Because they provide a clear and precise spatial distribution of primary and secondary carbonate phases at the sample scale, these maps constitute a valuable tool for selecting the position of subsamples for radiometric dating or environmental proxy analysis. The efficiency and reliability of our integrative approach is convincingly demonstrated by the remarkable coherence of U/Th ages both within and between speleothem samples.

Implementation of a portable EDXRF measurement chain for characterization of metallic objects of cultural interest in Colombia

The study of cultural heritage requires sophisticated equipment that does not alter or destroys the materials composing the objects under study. The main requirement about an artifact or an ancient work of art, for its restoration or conservation processes, is information about its constituting elements. Energy-dispersive X-ray fluorescence (EDXRF) is a very versatile and relatively inexpensive technique for conducting a nondestructive elemental analysis. In this paper, we present the design and implementation of a hand-hold X-ray fluorescence spectrometer. Although the EDXRF measurement chain appears to be a simple technique to assemble and use, it requires extensive knowledge about the proper handling of the X-ray beam, the analysis of the spectrum and whether the obtained spectrum is appropriate for a qualitative and quantitative analysis. Even geometry is one of the most important factors since the source-sample-detector distances must be handled with meticulousness to obtain optimal spectra. Acquisition time and the amount of accumulated counts to obtain high resolution spectral peaks are very important as well.This work shows the results obtained from metallic samples of Colombian cultural interest belonging to the collection of Museo Universitario Universidad de Antioquia.

Green methodology for quality control of elemental content of infant milk powder

A green methodology for the direct determination of elemental content in infant milk powder samples from 0 to 3 years was developed. A portable energy dispersive X-ray fluorescence (ED-XRF) tool has been used as a direct method for the quantification of five essential elements (Ca, K, Fe, Cu and Zn). For analysis pellets from 0.8 g of each sample weight were made and analyzed. Due to the high dependence of the ED-XRF signal with the sample matrix, external calibrations using cocoa powder diluted with glucose were performed. Infant milk samples were diluted with lactose and the signals were interpolated in the external calibrations. Concentrations obtained by ED-XRF were compared with the concentration found by Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) determination and those indicated in the package label of the corresponding milk samples. Direct determination by ED-XRF provides accurate results, and shows a good correlation with ICP-OES with r2 values ranging between 0.80 till 0.95. Limits of detection (LOD) were 114, 178, 14, 0.9 and 1.7 μg/g for Ca, K, Fe, Cu and Zn, respectively, being relative standard deviation (RSD) for real milk powder sample analysis lower than 10% for most of the elements.

Interdisciplinary examinations carried out on heterogeneous coarse ceramics from Neolithic lakeside settlements in the Northern Alpine Foreland (3900–3500 BCE): Analysis strategy and preliminary results from a test series using pXRF

In recent decades numerous Neolithic lakeside and wetland settlements have been investigated in Switzerland, southern Germany and eastern France. The finds from these settlements indicate that complex relationships and close contacts existed between the inhabitants of different settlements and regions. This can be seen in ceramic vessels that exhibit similarities to those from other regions based on their style, manufacturing technique and raw materials. Although the use of chemical and archaeometric analyses to determine the origin of pottery has been well established for years and despite promising investigations, such analyses have hardly ever been carried out in the study region; as a result, the topic of mobility has rarely been examined. In order to better understand mobility patterns in Neolithic societies by combining stylistic analyses with a chemical characterisation of the potter's clay used, this paper explores the use of portable energy dispersive X-ray fluorescence (pXRF) analysis as a means of chemically characterising ceramics. Since studies on the use of pXRF to examine handmade, heterogeneous and coarsely tempered ceramics are rare, it seems necessary to evaluate the method. This paper presents the development of a strategy for the analysis of large series of handmade coarse ceramics from prehistoric settlements. Two examples illustrate the possibilities of and limitations to pXRF analysis on pottery for the detection of mobility patterns of Neolithic societies in the Northern Alpine Foreland.

Recent Publications on Archaeological Ceramic Analyses and their Contributions to the Study of Ancient Pottery Technology

Recent Publications on Archaeological Ceramic Analyses and their Contributions to the Study of Ancient Pottery Technology

A type of portable micro-EDXRF spectrometer with laser displacement sensor

A portable micro energy dispersive X-ray fluorescence spectrometer with Laser Displacement Sensor (LDS) is reported in this paper. Due to irregular or curved surface of archaeological object, the distances between the irradiation spot of sample and exit of polycapillary X-ray optics can vary. In this paper, we employed a LDS in our portable micro-X-ray fluorescence spectrometer to control the distances between the irradiation spot on the sample and the exit of polycapillary X-ray optics in order to decrease the errors caused by the irregular or curved surfaces of samples. In order to test this spectrometer, elemental mapping analyses were carried on with and without LDS on an irregular colored glaze of a piece of curved ancient porcelain, the height difference of two parts of ancient porcelain being nearly 5 mm. From the results, it can be concluded that this spectrometer has potential application prospects in measuring irregular or curved surface of samples.

Characterization of building materials by means of spectral remote sensing: The example of Carcassonne's defensive wall (Aude, France)

Geological and archaeological analysis of stone masonries in standing structures helps reveal information about use of natural resources. At the same time, the study of historical materials is useful for conservators and cultural heritage management. Geochemical and petrographic analysis of building material types is usually done through destructive analysis on a few selected samples and can be problematic due to the costs of operations and the size of buildings themselves. This paper demonstrates that the combination of hyperspectral imaging portable Near Infrared (NIR) spectroscopy and Energy Dispersive X-ray Fluorescence (ED-XRF) spectroscopy can be useful for analysing types of raw materials used in distinct construction phases of the inner defensive wall in the citadel of Carcassonne (Aude, France). Stratigraphic analysis of the architecture, short-range spectral remote sensing and portable ED-XRF measurements were combined in an interdisciplinary approach to classify sandstone elements. The experimental protocol for in situ non-destructive analysis and classification of the masonry types allows the investigation of the monument in a diachronic perspective, collecting information to delineate raw materials varieties and their use or re-use through time.

Direct determination by portable ED-XRF of mineral profile in cocoa powder samples.

The present study has exploited the rapidity of the analysis and the multi-elemental capability of the energy dispersive X- ray fluorescence (ED-XRF) technique for the mineral profile determination in cocoa powder. A fast, cheap and environmental sustainable method without reagent consumption or toxic waste generation has been proposed. The samples can be prepared in the form of pellets of 13 mm in diameter and 2-3 mm thickness. The different internal calibrations used by ED-XRF equipment did not provide accurate results when comparing the mineral profile with the concentration obtained by Inductively Couple Plasma Optical Emission Spectroscopy (ICP-OES) after microwave assisted digestion of samples. For direct ED-XRF analysis of the cocoa samples, an external calibration using as standards the cocoa samples diluted with sugar was prepared. The analytical parameters of Relative Standard Deviation and Limit of Detection for the determined elements are adequate to the concentration levels found in the samples.

Near-infrared spectroscopy and X-ray fluorescence data fusion for olive leaf analysis and crop nutritional status determination

Leaf analysis is a useful way of diagnosing the nutritional status of the plants and therefore fast methods of analysis are demanded to aid in fertilization management decisions. In this work, a strategy based on the combined use of near-infrared spectroscopy (NIR) and portable energy dispersive X-Ray Fluorescence (EDXRF) is proposed as a suitable cheap and rapid alternative to traditional wet analytical methodologies. The approach has the major benefit of minimal sample preparation since leaves need to be only dried and ground. The ability of both techniques individually and applying two strategies of data fusion for the prediction of the most important plant nutrients, namely N, P, K, Ca, Mg, Mn, Zn, and B was tested. Predictive models were constructed using Partial Least Squares (PLS) to correlate the spectra with the nutrient contents. Models of unequal prediction performance in terms of the ratio of predictive deviation (RPD) were obtained for the different parameters when considering both techniques separately. Low-level data fusion, which consists of a concatenation of the raw data from both techniques, showed little improvement and even decreased the predictive ability for some elements. Better results were obtained with mid-level data fusion, that is, merging data after a feature extraction step performed by means of Principal components analysis (PCA). The results show that a fair quantitative prediction is possible for Ca, K and Mn with RPDs ≥ 2 for external validation, whereas models for N and P allowed a semiquantitative estimation. Mg and B models were less satisfactory and can be used only for distinguish between low and high levels, while Zn content cannot be predicted. Finally, the potential of the fusion of FT-NIR and EDXRF spectroscopic data for the fast screening of olive crop nutritional status has been tested. Deficiencies in important elements like N and K has been successfully detected.

Chronological Classification of Ancient Mortars Employing Spectroscopy and Spectrometry Techniques: Sagunto (Valencia, Spain) Case

Forty-two mortar samples, from two archaeological excavations located in Sagunto (Valencian Community, Spain), were analysed by both portable energy dispersive X-ray fluorescence spectroscopy (pED-XRF) and inductively coupled plasma mass spectrometry (ICP-MS) to determine major and minor elements and traces including rare earth elements (REEs). Collected data were crossed with those previously obtained from Sagunto Castle mortars, and principal component analysis (PCA) was applied to discriminate the construction phases of the unearthed buildings. REE permitted to ascribe most of the masonries to the Roman Imperial period. Moreover, a statistical model was built by employing partial least squares discriminant analysis (PLS-DA) in order to classify the mortars from Roman Imperial period and from Islamic period due to the problematic overlapping between these two phases. Results confirmed the effectiveness of the developed indirect chronology method, based on REE data, to discriminate among historic mortars from different construction periods on a wide scale including different Sagunto archaeological sites.