Nitrogen determination by SEM‐EDS and elemental analysis

This paper describes a methodology for the analysis of nitrogen by scanning electron microscope with an energy dispersive X‐ray spectrometer (SEM‐EDS). The methodology was developed to have a rapid and accurate alternative method to the elemental analysis by combustion and thermoconductivity detection that does not imply the decomposition of the sample. Two methods by SEM‐EDS were established: a quantitative method trying to construct a calibration curve with reference materials and another using the standardless method provided with the instrument software, and the results were compared with those obtained by elemental analysis using two instruments that work at different temperature. An important matrix effect was found when trying to construct a calibration curve for SEM‐EDS for any kind of material, being corrected when using the standardless method because this method corrects the matrix effect. The quantification of nitrogen by SEM‐EDS is a good alternative to elemental analysis by combustion and thermoconductivity detection in those cases where the sample has a very high decomposition temperature. Copyright © 2013 John Wiley & Sons, Ltd.     

Analysis of confiscated fireworks using Raman spectroscopy assisted with SEM‐EDS and FTIR

A forensic analysis of several samples of pyrotechnic artefacts was performed by Raman spectroscopy assisted by scanning electron microscopy/energy‐dispersive X‐ray spectroscopy (SEM‐EDS) and Fourier transform infrared (FTIR) analysis. Among the components, several nitrates, ammonium perchlorate, nitrocellulose, metallic titanium particles and shellac were detected. The combination of Raman spectroscopy and SEM‐EDS showed very useful performance. All components were detected by Raman spectroscopy except for shellac, kaolinite and titanium particles, which were not conclusive enough and had to be determined by FTIR and EDS. In contrast, many compounds were not detected by FTIR. Copyright © 2011 John Wiley & Sons, Ltd.     

Pigment analysis of Portuguese portrait miniatures of 17th and 18th centuries by Raman Microscopy and SEM‐EDS

Seventeen Portuguese miniature portraits on copper support from the Évora Museum collection (Portugal) were analyzed in situ and nondestructively by Raman microscopy (RM), SEM‐EDS, and stereomicroscopy. This work constitutes a great breakthrough in the study of miniature paintings from the 17^th and 18^th centuries, since the chemical information known about this unique kind of paintings are still scarce, and in particular, this exclusive collection was never been subjected to any physicochemical study. In this work, each portrait was examined in detail in order to characterize the pigments palette used by the miniaturists. The μ‐Raman analysis, in particular, guaranteed an exceptional visualization and good individual identification of small grains of pigments and other constituents of the pictorial layer. Using this technique, 19 compounds were identified, including bluish black covellite, a pigment rarely found in oil paintings. SEM‐EDS was used as an important complementary technique to confirm the chemical nature of some pigments and to identify shell gold (gold dust) in some portraits. Overall, the pigments identified in this large set of old paintings are broadly consistent with those mentioned in the painting treatises of that time or reported in other more modern bibliographic sources. Copyright © 2014 John Wiley & Sons, Ltd.     

Depth‐selective elemental imaging of microSD card by confocal micro XRF analysis

A semiconductor device, a microSD card, was measured by using two XRF instruments. 2D elemental images were obtained using a micro‐XRF system with a spatial resolution of 10 µm. Elemental distributions of the near‐surface region of the sample were clearly shown. Titanium was observed in the resin constituting the sample. Nickel and gold were observed on a terminal and localization of the sample. Elemental distribution of copper reflected the circuit structure of the measurement area that was in the neighborhood of the sample surface. Moreover, the elemental depth distributions of the sample were measured by using a confocal micro‐XRF instrument. The confocal micro‐XRF instrument was constructed in the laboratory with fine‐focus polycapillary x‐ray optics. The depth resolution of the developed spectrometer was 13.7 µm at an energy of Au Lβ (11.4 keV). The elemental images obtained at near‐surface by confocal micro‐XRF were the same as the results obtained from 2D micro‐XRF. However, different Cu images were obtained at a depth of several tens of micrometers. This indicates that microSD cards consist of a few different Cu‐circuit structure designs. The elemental depth distributions of each circuit structure of the semiconductor device were clearly shown by confocal micro‐XRF. Copyright © 2013 John Wiley & Sons, Ltd.     

Inclusions and metal composition of ancient copper‐based artefacts: a diachronic view by micro‐EDXRF and SEM‐EDS

A diachronic view of the metallurgy in the Portuguese territory during the first three millennia after its appearance in the Iberian Peninsula is presented based on the current state of the art. Results of micro‐energy dispersive X‐ray fluorescence (micro‐EDXRF) analyses made on metal artefacts to determine their composition and scanning electron microscopy with energy dispersive analysis (SEM‐EDS) analyses to study microstructural features as inclusions are shown to illustrate trends and specificities of each chronological period. Generally, in early periods, namely during the Copper Age and first stages of the Bronze Age, unalloyed copper and arsenical copper were at use, and only by the Late Bronze Age (LBA) did tin bronze substitute almost completely the previous role of copper. In the Early Iron Age, during the Orientalising period, a general decrease in the average tin content in bronzes seems to happen. Regarding the inclusions observed in the metal matrix, these seem to suffer a diversification with the appearance of tin bronzes. By the Copper Age, only Cu? O and Cu? As? O inclusions are observed, while by the LBA Cu? S inclusions become regular, besides others less frequent, as Sn? O, Cu? S? Fe and Pb globules. Overall, with the present analytical study, the complementary character of micro‐EDXRF and SEM‐EDS in the study of ancient metals is demonstrated, providing a first general overview of the ancient metallurgy at the Portuguese territory which is of key importance to specific investigations of the future. Copyright © 2011 John Wiley & Sons, Ltd.     

Nondestructive elemental depth profiling of Japanese lacquerware ‘Tamamushi‐nuri’ by confocal 3D‐XRF analysis in comparison with micro GE‐XRF

We have applied recently two XRF (micro x‐ray fluorescence) methods [micro‐Grazing Exit XRF (GE‐XRF) and confocal 3D‐XRF] to Japanese lacquerware ‘Tamamushi‐nuri.’ A laboratory grazing‐exit XRF (GE‐XRF) instrument was developed in combination with a micro‐XRF setup. A micro x‐ray beam was produced by a single capillary and a pinhole aperture. Elemental x‐ray images (2D images) obtained at different analyzing depths by micro GE‐XRF have been reported. However, it was difficult to directly obtain depth‐selective x‐ray spectra and 2D images. A 3D XRF instrument using two independent polycapillary x‐ray lenses and two x‐ray sources (Cr and Mo targets) was also applied to the same sample. 2D XRF images of a Japanese lacquerware showed specific distributions of elements at the different depths, indicating that ‘Tamamushi‐nuri’ lacquerware has a layered structure. The merits and disadvantages of both the micro GE‐XRF and confocal micro XRF methods are discussed. Copyright © 2009 John Wiley & Sons, Ltd.     

Uncertainty and traceability in alloy analysis by borate fusion and XRF

Owing to the increasing demand for compliance with quality system standards, analytical laboratories may need to demonstrate the traceability of their results to the International System of Units (SI) or to the values of a certified reference material. To do that, they need to demonstrate the components of uncertainty in their analytical work. At NIST, the goal is to demonstrate traceability to SI units to ensure that results are accepted on a worldwide basis. For XRF spectrometry with borate fusion, traceability to SI is achieved through calibration with spectrometric solution standards or high‐purity compounds. The method is capable of achieving relative expanded uncertainty estimates (95% confidence level) of 1% or lower. In this paper, the capability is demonstrated for low alloy‐steel and an Al? Ti? Nb? W aerospace alloy. XRF results are compared with certified values and with results from atomic emission methods through a simple bias test. NIST uses the borate fusion/XRF method as part of the value assignment process for Standard Reference Materials^®. Copyright © 2004 John Wiley & Sons, Ltd.     

Archaeometric study of possible Ninevite‐5 pottery from upper Tigris region using SEM‐EDS,PEDXRF, and OM

This study aims to reveal the production technology of some representative samples of possible Ninevite‐5 potsherds which are generally dated between the Early Jezirah I to EJ‐II/EJ‐III periods (roughly 3000–2500 bc ) and accepted as the typical ceramics reflecting the northern Mesopotamian culture in the first half of the 3rd millennium BC. The samples were selected from the archeological excavation area of Kuriki (upper Tigris region, Turkey) and exposed to multiple analytical techniques including scanning electron microscopy with an energy dispersive spectrometer, optical microscopy, and polarized energy dispersive X‐ray fluorescence spectrometry. The results showed that all the samples have high amounts of CaO (up to 29.83 wt.%) indicating use of calcareous clay deposits and they have an analogous chemical compositions in terms of both major oxides and trace elements which implied the use of the same raw materials. The vitrification degrees of the samples, examined by back scattered electron images, suggested that the firing temperature of the potsherds did not exceed the range of 800–900°C. It was also revealed that the firing atmosphere was oxidative which would be attributed to use of kiln firing rather than a bonfire or pit firing. Both the chemical and petrographic results suggested that the investigated samples presumably belong to a regional (upper Tigris) production rather than a local one.     

Analysis of the chromite inclusions found in nephrite minerals obtained from different deposits using SEM‐EDS and LRS

Scanning electron microscopy with energy dispersive spectrometer (SEM‐EDS) and laser Raman spectroscopy (LRS) were used to analyse the chromite inclusions found in four samples of the mineral nephrite that were obtained from Taiwan (one), Manasi in China (two) and New Zealand (one). The chromite inclusions found in sample HL‐1 (Taiwan) contain low contents of Mg and Al, as well as a characteristically high Zn content. The most significant finding, however, was that HL‐1 could also be distinguished from the other samples by the lower wavenumbers of the positions of the peaks that belong to the A_1g, F_2g⁽¹⁾ and E_g modes. Compared to the difference in compositions, the difference in the positions of the peaks in the Raman spectra of the chromite inclusions, as revealed by LRS, can more easily be used to distinguish between samples of nephrite that have been obtained from different deposits, and in particular to identify the provenance of the raw material used in ancient nephrite artefacts, in view of the fact that LRS is non‐destructive and easy to apply. Copyright © 2011 John Wiley & Sons, Ltd.     

Characterization of a Namban folding screen from the Edo period by means of EDXRF,SEM‐EDS and Raman spectroscopy

In this work, a multianalytical approach is employed to characterize the materials used in a Namban folding screen that depicts the arrival of the Portuguese to the port of Nagasaki. Portuguese sailors reached Japan in 1543 and initiated what was to be known as the Namban trade. This interaction between Portuguese and Japanese was meticulously recorded by artists in the form of valuable and rare folding screens. The present screen, attributed to the Edo period (~1603–1868), is what we could consider a second‐generation screen, a copy of scenes and characters that appear in screens from the Momoyama period (~1573–1603) but in increased scale and minor detail. The materials used in the screen were identified by means of in situ energy dispersive X‐ray fluorescence. Complementary results were obtained by Raman and scanning electron microscopy coupled to energy dispersive spectrometry analysis of microsamples taken from the screen. The palette used in this artwork resorts to gold, malachite, azurite, vermillion, red lead, white oyster shell, and carbon black. Differences were found, when compared with previously studied screens, i.e. the use of mixtures of pigments, namely vermillion with red lead in an orange shade of red and also the mixture of vermillion and carbon black to obtain a brown color. Special emphasis was given to the characterization of the golden areas and study of techniques of gold application. Copyright © 2013 John Wiley & Sons, Ltd.     

ED‐XRF set‐up for size‐segregated aerosol samples analysis

The knowledge of size‐segregated elemental concentrations in atmospheric particulate matter (PM) gives a useful contribution to the complete chemical characterisation; this information can be obtained by sampling with multi‐stage cascade impactors. In this work, samples were collected using a low‐pressure 12‐stage Small Deposit Impactor and a 13‐stage rotating Micro Orifice Uniform Deposit Impactor^?. Both impactors collect the aerosol in an inhomogeneous geometry, which needs a special set‐up for X‐ray analysis. This work aims at setting up an energy dispersive X‐ray fluorescence (ED‐XRF) spectrometer to analyse quantitatively size‐segregated samples obtained by these impactors. The analysis of cascade impactor samples by ED‐XRF is not customary; therefore, as additional consistency test some samples were analysed also by particle‐induced X‐ray emission (PIXE), which is more frequently applied to size‐segregated samples characterised by small PM quantities. A very good agreement between ED‐XRF and PIXE results was obtained for all the detected elements in samples collected with both impactors. The good inter‐comparability proves that our methodology is reliable for analysing size‐segregated samples by ED‐XRF technique. The advantage of this approach is that ED‐XRF is cheaper, easier to use, and more widespread than PIXE, thus promoting an intensive use of multi‐stage impactors. Copyright © 2011 John Wiley & Sons, Ltd.     

Development of a high‐resolution confocal micro‐XRF instrument equipped with a vacuum chamber

A confocal micro‐X‐ray fluorescence (micro‐XRF) instrument equipped with a vacuum chamber was newly developed. The instrument is operated under a vacuum condition to reduce the absorption of XRF in the atmosphere. Thin metal layers were developed to evaluate the confocal volume, corresponding to depth resolution. A set of thin metal layers (Al, Ti, Cr, Fe, Ni, Cu, Zr, Mo, and Au) was prepared by a magnetron sputtering technique. The depth resolutions of the new instrument were varied from 56.0 to 10.9 µm for an energy range from 1.4 to 17.4 keV, respectively. The lower limit of detection (LLD) was estimated by comparison with a glass standard reference material NIST SRM 621). The LLDs obtained by a conventional micro‐XRF were compared with the LLDs obtained by a confocal micro‐XRF instrument. The LLDs were improved in the measurement under confocal configuration because of the reduction of background intensity. Finally, layered materials related to forensic investigation were measured. The confocal micro‐XRF instrument was able to nondestructively obtain the distribution of light elements that cannot be detected by measurement in air. Copyright © 2013 John Wiley & Sons, Ltd.     

Accurate determination of the Ca:P ratio in rough hydroxyapatite samples by SEM‐EDS,PIXE and RBS—a comparative study

The Ca:P ratio in a certified standard of hydroxyapatite was determined by X‐ray spectrometry (XRS), with the X‐rays excited by both electrons and ions using energy dispersive spectroscopy on the scanning electron microscope (SEM‐EDS) and particle‐induced X‐ray emission (PIXE). The certified value of Ca:P was accurately verified by 3 MeV ⁴He⁺ Rutherford Backscattering Spectrometry (RBS). We show that the demonstrably rough surface of this sample does not cause perturbation of the Ca:P ratio within the uncertainties of each of the XRS measurements. Copyright © 2009 John Wiley & Sons, Ltd.     

XRF analysis of arsenic‐doped skin phantoms

Chronic arsenic poisoning can lead to serious health problems including vascular disorders and cancer. Therefore, the development of a system to measure arsenic in vivo would be useful in monitoring exposure. In particular, as skin is one of the tissues in which arsenic has health consequences and is stored for a prolonged period of time, an in vivo measure of skin arsenic content would be a clinically useful measure of chronic exposure. The preliminary development of an x‐ray fluorescence system to measure arsenic in vivo is reported. Standard addition arsenic‐ doped polyester resin phantoms were prepared, and the fluorescence induced by silver K x‐rays from a ¹⁰⁹Cd source was measured. Preliminary estimates of detection limits for an 8 mm thick phantom and an effective dose of ～0.3 µSv are 3.5 ± 0.2 and 10.3 ± 0.5 ppm in 90 and 180° measurement geometries, respectively, for a measurement time of 30 min. Copyright © 2004 John Wiley & Sons, Ltd.     

Comparison of cartridge case and airborne GSR—a study of the elemental composition and morphology by means of SEM‐EDX

A comparative study of the properties of gunshot residue (GSR) collected from shooter's hands and from inside the case of the same cartridge used in a shooting experiment was performed. Three types of popular Luger 9 mm ammunition were chosen with primer mixtures based on different types of detonators: mercury fulminate, lead styphnate or lead azide and an organic one, e.g. diazodinitrophenol. Two modifications of lead‐free ammunition, with copper and tin plated projectiles were used. Samples of GSR were examined by means of scanning electron microscopy and energy dispersive X ‐ray spectrometry. Both, similarities and differences in the chemical composition and morphology of GSR secured from the hands of the shooting person and from the appropriate cartridge case were observed. The chemical composition of the characteristic gunshot particles originating from the primer may be influenced by the chemical composition of other parts of the cartridge case, especially the core and the jacket of the projectile. Thus, the distribution of the chemical elements in GSR strongly depends on the direction of the reaction path starting in the primer cup placed at the bottom of the cartridge case, moving along the cartridge case and finishing when the projectile leaves the gun muzzle. A reliable comparison of the airborne residue to these taken from cartridge case for forensic purposes requires some experience based on laboratory experiments performed under controlled conditions. Copyright © 2007 John Wiley & Sons, Ltd.     

Determination of gold,platinum and uranium in South African ores by high‐energy XRF spectrometry

An automated energy‐dispersive x‐ray fluorescence spectrometer, called the AZTEC, was developed for the non‐destructive determination of gold, platinum and uranium in Witwatersrand ores, by utilizing the high‐energy spectral regions of the K x‐ray lines of these elements. It provides a viable alternative to fire assay, and measures gold concentrations down to <1 ppm. About 100 g of pulverized sample are presented for analysis in a 20 mm diameter tube, and the fluorescent x‐rays are detected by an array of up to 12 high‐purity germanium detectors. Count‐rates of up to 10⁶ counts per second per detector can be processed by the signal processing electronics. The AZTEC technique is a variant of the scattered radiation technique. Concentration is related to peak intensities corrected for background, matrix variations, density and line overlaps. Provided that the samples are finely pulverised, the AZTEC analyses compare well with those obtained by fire assay. Production instruments are being used mainly in the gold mining industry, where they have analysed over 10⁷ samples to date. Copyright © 2004 John Wiley & Sons, Ltd.     

The elemental composition of Stradivari's musical instruments: new results through non‐invasive EDXRF analysis

During recent decades, many researchers have tried to understand the main influences on the extraordinary sound and beauty of the masterpieces made by the ancient violin makers. This is still a challenge for many others today. Mainly because of a lack of written historical documents, the rediscovery of some of the ancient violin‐making processes was made possible thanks to scientific analyses performed on their materials by means of diagnostic techniques. However, understanding which substances were adopted is a very hard task, because the analyses are influenced by many factors: for example, alterations, wear, retouches, and the heterogeneity of materials. This paper presents some new EDXRF results collected on eight‐stringed musical instruments made by Antonio Stradivari between 1669 and 1734 (“Clisbee” 1669, “Hellier” 1679, “Ford‐Rougemont” 1703, “Joachim‐Ma” 1714, “Russian Federation” viola 1715, “Cremonese” 1715, “Vesuvius” 1727, and “Scotland” 1734) and now preserved at the Museo del Violino in Cremona. A brief comparison with a modern violin made by Simone Ferdinando Sacconi (“Hellier copy” 1941), one of the most eminent violin makers of the 20th century and one of the greatest experts on Stradivari's work, is also provided. This represents the first comparative analysis of a wide number of ancient musical instruments made by the same violin maker over an extended period. A non‐destructive and non‐invasive approach was followed to (a) understand the elemental composition differences between the best conserved and most worn‐out surfaces; (b) check if there are elemental similarities among the finishing materials of violins made in different years by the same violin maker; (c) give new suggestions about the materials used. To distinguish the best conserved areas from the worn‐out ones, a preliminary investigation by UV‐induced fluorescence photography was performed. In addition, stereomicroscopic observations and Fourier transform infrared spectroscopy (FTIR) analyses were performed on selected areas to validate the hypotheses. The results, in some cases comparable with previous research on Stradivari instruments, have increased the pool of information about materials and treatments adopted in the Stradivari workshop.     

A modular system for XRF and XRD applications consisting of a microfocus X‐ray source and different capillary optics

In recent years, new components for x‐ray analysis have been developed: capillary optics, microfocus x‐ray tubes and compact detectors, e.g. energy‐dispersive detectors without liquid nitrogen cooling. Microfocus tubes have a relatively low power but their brightness is up to 100 times higher than for normal x‐ray tubes which are used in diffractometry. A combination of these tubes with highly efficient capillary optical elements allows one to obtain parallel or focused beams of high intensity. Combining such a special source with detectors of different kinds, a compact system can be realized which may be successfully used in micro‐XRF, in diffraction and microdiffraction, etc. The system presented is designed in a modular way so that the components may be replaced by each other. Some examples of applications of such systems are reported. Copyright © 2004 John Wiley & Sons, Ltd.     

Quantitative analysis of sulphides and sulphates by WD‐XRF: Capability and constraints

In the course of geochemical characterisations, total sulphur analyses are common practice although a differentiated quantification of sulphur species could provide valuable additional information, particularly when samples from unclear or changing redox environments are investigated. Unfortunately, a likewise simple distinct determination of just sulphide and sulphate already requires considerable efforts as sample dissolution or extra equipment. Two comparatively convenient strategies based on extended routine wavelength dispersive X‐ray fluorescence spectrometry measurements were adapted and optimised for a reliable quantitative sulphur speciation whereupon the matrix influence can be neglected. About 100 synthetic samples with different concentration ratios of sulphides and sulphates have been prepared and analysed using a WD‐XRF spectrometer. The first approach to differentiate between oxidation states and their quantification takes advantage of the Kα_1,2 doublet shift. Sulphide lines are located at 2309 eV, sulphate lines at 2310 eV, and mixtures can be quantified by a regression curve of fluorescence energy versus sulphide amount. Secondly, the amount of sulphide can be calculated by a regression curve based on the quotient Kβ′/Kβ of the sulphur peak heights or areas. In contrast to sulphides, sulphates show sulphur Kβ′ satellite peaks, and the intensity of S Kβ′ increases with the increasing sulphate content. However, the applicability of this second method is limited by the lower detection limit of sulphide (10 g kg^?1 sulphide in the sample) and interferences with lead (Pb Mβ line). Both approaches are validated by an independent method, Electrothermal Vaporisation Inductively Coupled Plasma Optical Emission Spectrometry, and already employed in investigations of ore‐containing mining dumps in Saxony/Germany. Copyright © 2016 John Wiley & Sons, Ltd.     

Large‐surface‐area diamond (111) crystal plates for applications in high‐heat‐load wavefront‐preserving X‐ray crystal optics

Fabrication and results of high‐resolution X‐ray topography characterization of diamond single‐crystal plates with large surface area (10 mm × 10 mm) and (111) crystal surface orientation for applications in high‐heat‐load X‐ray crystal optics are reported. The plates were fabricated by laser‐cutting of the (111) facets of diamond crystals grown using high‐pressure high‐temperature methods. The intrinsic crystal quality of a selected 3 mm × 7 mm crystal region of one of the studied samples was found to be suitable for applications in wavefront‐preserving high‐heat‐load crystal optics. Wavefront characterization was performed using sequential X‐ray diffraction topography in the pseudo plane wave configuration and data analysis using rocking‐curve topography. The variations of the rocking‐curve width and peak position measured with a spatial resolution of 13 µm × 13 µm over the selected region were found to be less than 1 µrad.