Analytische Chemie
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Eingeladener Vortrag
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We have obtained a minute amount of dry ink scratched from the bronze inkwell MS 1655/2. The powder was stored between two glass slides to minimize contamination. For micro analysis by FTIR a sample of the ink powder was transferred into a diamond cell while for confocal Raman spectroscopy a micro sample was placed onto sticky tape. The same portion of the sample was also investigated by scanning electron microscopy, where the elements distribution was determined by EDX.
The aim of our work was to check whether the assumption that the jar was discovered in Qumran can be substantiated. In order to establish the archaeological provenance of the jar we conducted a series of analytical tests on samples of material collected from the jar in April and June 2009. The samples were either found loose within the jar, these being probably constituted by remnants of its original contents, or were clay detached from the inner and outer surface of the jar. In addition, a portion of sand deposit coating the inside of the jar handles was analysed.
Lead (Pb) isotope amount ratios are commonly used in applications ranging from archaeology and forensic sciences to terrestrial and extra-terrestrial geochemistry. Despite their utility and frequency of use, only three certified isotope amount ratio reference materials are currently available for Pb: NIST SRMs 981, 982 and 983. Because SRM 981 has a natural Pb isotopic composition, it is mainly used for correcting instrumental mass discrimination or fractionation. This means that, at present, there are no other certified isotope reference materials with natural Pb isotopic composition that could be used for validating or verifying an analytical procedure involving the measurement of Pb isotope amount ratios.
To fill this gap, two new reference materials, both certified for their Pb isotopic composition, have been produced together with a complete uncertainty assessment. These new reference materials offer SI traceability and an independent means of validating or verifying analytical procedures used to produce Pb isotope amount ratio measurements.
ERM-EB400 is a bronze material containing a nominal Pb mass fraction of 45 mg/kg. ERM-AE142 is a high purity solution of Pb with a nominal mass fraction of 100 mg/kg. Both materials have been specifically produced to assist analysts in verifying or validating their analytical procedures. Note that while one of these reference materials requires the chemical separation of Pb from its matrix (ERM-EB400), the other does not (ERM-AE142). Details on the certification of these isotope reference materials are provided in this report.
Selective Electron Beam Melting (SEBM) is a promising powder bed Additive Manufacturing (AM) technique for near net-shape manufacturing of high-value titanium components. However, as with every emerging technique, the manufacturing processes can still be greatly improved and optimised. In particular, the links between AM settings and the resulting sample porosity is of great interest, as the fatigue life of SEBM parts is currently dominated by the presence of porosity. In this study, the size, volume fraction, and spatial distribution of the pores in model samples have been characterised in 3D, using X-ray Computed Tomography (CT), and correlated to the SEBM process variables. A strong relationship was found with the different beam strategies used to contour, and infill by hatching, a part section. The majority of pores were found to be small spherical gas pores, concentrated in the infill hatched region. Rarer irregular shaped pores were mostly located in the contour region and have been attributed to a lack of fusion between powder particles.
The lecture will discuss the sensitive issue of authentication of the objects of cultural heritage of immense cultural and monetary value if certified to be genuine. It will be made clear that material analysis alone, especially its non-destructive variety conducted by specialists in a single technique, can not prove that the object is genuine. The best material analysis can do, after all appropriate tests have been conducted, is to announce that nothing has been found that contradicts the assumption of genuineness. Moreover, the results of the natural analysis can never be used as the only justification of the authentication in the cases of composite objects such as manuscripts or epigraphs. A certification always requires the expertise of the specialist in the field (be it a historian, paleographer, epigrapher, etc.), whose judgment can be at the most supported by appropriate material analysis.
The most effective approach for testing suspicious artifacts has been established by the forensic science. Here, not the authentication, but the determination of the forgery stands in the focus of the work. Investigation protocols developed within 150 years and constantly improved include a clear statement of the analysis purpose and the definition of plausibility criteria for the possible outcome. The younger sister of the forensics, archaeometry has to overcome additional obstacles such as the heterogeneity of historic material coupled with the scarcity of suitable reference material. Over the last two decades the popularity of archaeometric studies has increased enormously, with the industry-driven development of so-called non-destructive technologies (NDT) that do not require sampling. Further technological developments led to the appearance of NDT methods with extremely small interaction windows (µm range). Each of these methods has limitations that have to be carefully considered when planning the tests of a heterogeneous and often partially degraded historical material. This approach is inherently multi-instrumental, therefore archaeometric and forensic departments unite a number of specialists who work together defining the tasks and the methods involved for their successful completion.
The experimental knowledge about the inks of antiquity and late antiquity rarely goes beyond their visual description. In rare cases, inks typology has been determined by means of microscopy and reflectography, i.e. using their physical and optical properties, respectively. Soot, plant, and iron gall inks form different typological classes of historical black writing materials. Soot ink is a fine dispersion of carbon pigments in a water-soluble binding agent; plant-based ink consists of tannin solution; iron gall-ink presents a boundary case between soot and plant ink— a water soluble preliminary stage (similar to inks from the second group) oxidizes and evolves into a black, insoluble material (similar to the carbon pigments of the first group) when the writing is exposed to air. Each ink class has distinct properties that would readily permit their easy differentiation, if only these historical inks always belonged to just one of the classes above. In reality, inks may contain additives that obscure a clear picture.
All the black inks of the DSS have been hitherto identified as soot inks. Yet some manuscripts, with 1QapGen ar among them, display ink corrosion that is incompatible with the pure soot ink. This type of corrosion commonly observed in medieval manuscripts written with iron gall inks, results from the catalytic action of metallic component in the ink. Early analysis of this ink conducted by Nir El and Broshi in 1996 found copper in the corrosive inks and attributed its presence to the use of bronze inkwells. Re-investigation of the 1QapGen ar ink suggests, however, that the ink composition, soot + copper, agrees well with the ink recipe recorded in the 1st century CE by Dioscorides. Similar inks have been already attested on contemporary Egyptian papyri. The first part of the paper is dedicated to the new results on the inks and corrosion pattern of the 1QapGen ar.
In the second part of the presentation I will focus on the luxury scrolls, a distinct codicological type introduced by E. Tov. Our studies show that the preparation of the writing materials cannot supplement the list of codicological criteria offered by Tov. Therefore, one can divorce the writing material production from its inscription in contrast with the medieval scriptoria practices that included parchment production and copying of the manuscripts.
Material study of inks
(2016)
Our experimental knowledge about the inks of antiquity and late antiquity rarely goes beyond their visual description. In rare cases, inks typology has been determined by means of microscopy and reflectography, i.e. using their physical and optical properties, respectively. Soot, plant, and iron gall inks form different typological classes of historical black writing materials. Soot ink is a fine dispersion of carbon pigments in a water-soluble binding agent; plant-based ink consists of tannin solution; iron gall-ink presents a boundary case between soot and plant ink— a water soluble preliminary stage (similar to inks from the second group) oxidizes and evolves into a black, insoluble material (similar to the carbon pigments of the first group) when the writing is exposed to air. Each ink class has distinct properties that would readily permit their easy differentiation, if only these historical inks always belonged to just one of the classes above. In reality, inks may contain additives that obscure a clear picture.
Even crude observations suggest that the inks of antiquity differed greatly in their composition. We believe, that reconstructing the ink recipes with the help of advanced non-destructive analytical techniques could serve as a powerful accessory in the studies of ancient papyri.
The proposed paper will present a short survey of the methods of material analysis and the challenges offered by ancient inks. (Two) examples of ink studies from the collections of the Israel Museum in Jerusalem and Egyptian Museum in Berlin will conclude the paper.
The international Qumran project coordinated at the BAM, Berlin, resulted in an integrated methodology for determining the original and acquired properties of the skin-based writing surfaces of the Dead Sea Scrolls. This methodology offers a powerful tool for addressing such questions as the provenance, sorting and comparison of manuscripts. In addition, we have developed specific protocols for on-site studies, which were successfully applied to the fragments from the Schøyen collection in Norway. Our studies show that the Dead Sea Scrolls writing surfaces can be divided roughly into three groups: leather, parchments of a light tint, and those of various shades of brown. The latter ones are invariably tanned, whereas the middle group is characterized by the presence of various inorganic salts. Some of the pale parchments, among them the Temple Scroll (11Q19), are remarkably similar to medieval European parchment. Therefore we have formulated the working theory that in the Judaea of the Hellenistic period two different parchment-making traditions existed side by side: an ‘eastern’ one (represented by the tanned parchments of Qumran, closely resembling Aramaic documents from the fifth century BC, and a ‘western’ one (represented by the untanned/lightly tanned ones similar to early Christian Greek parchments).
This division has found support during our first pilot study of the Geniza fragments, in which Babylonian and Palestinian traditions seem to follow the “eastern” and “western” technologies, respectively.
The evolution and socio-geographic distribution of writing inks in late Antiquity and the early Middle Ages build the second focus of the BAM group. We use X-ray fluorescence analysis (XRF) to determine the chemical composition of the inks and NIR-reflectography for their typology. Here the early appearance of the metal containing inks clearly belongs to the western tradition as opposed to the continuous use of soot inks in the East.
Investigation of manuscripts found in sites along the Silk Road shows the history of communication and exchange between Asia and the Mediterranean over the centuries. Different scripts and languages preserved on paper in certain styles provide information about traditions and provenance.
To get an idea of the cultural background of the highly developed painting techniques obvious in some illuminated manuscripts, the material used for writing and painting is analyzed. Singular Sogdian and Tocharian manuscripts from Turfan show text on one side with a colorful painting on the other side of the document. In comparison with other productions of different periods or usages from the site, special features are worked out to characterize cultural roots or influence in the network of relationships. Details analyzed in the most elaborated documents Show various influences led to the colorful masterpieces.
Similar to the success story of digital photography a major upheaval has been observed in digital industrial radiology. This paper is split into 3 parts:
Part 1: Film Replacement and Backscatter Imaging: Computed radiography with phosphor imaging plates substitutes film applications. Digital Detector Arrays enable an extraordinary increase of contrast sensitivity in comparison to film radiography. The increased sensitivity of digital detectors enables the efficient usage for dimensional measurements and functionality tests substituting manual maintenance. The digital measurement of wall thickness and corrosion status is state of the art in petrochemical industry. Photon counting and energy discriminating detectors are applied up to 300 Kv provide increased thickness dynamic and material discrimination by synchronously acquisition of images of the high and low energy part of the spectrum. X-ray back scatter techniques have been applied in safety and security relevant applications with single sided access of source and detector. First inspections of CFRP in aerospace industry were successfully conducted with newly designed back scatter cameras. Numeric modeling is used to design X-Ray optics and inspection scenarios as well as conducting RT training.
Part 2: Computed tomography (CT)
Part 3: Micro Radiography and Micro CT.
Designing artificial macromolecules with absolute sequence order represents a considerable challenge. Here we report an advanced light-induced avenue to monodisperse sequencedefined functional linear macromolecules up to decamers via a unique photochemical approach. The versatility of the synthetic strategy—combining sequential and modular concepts—enables the synthesis of perfect macromolecules varying in chemical constitution and topology. Specific functions are placed at arbitrary positions along the chain via the successive addition of monomer units and blocks, leading to a library of functional homopolymers, alternating copolymers and block copolymers. The in-depth characterization of each sequence-defined chain confirms the precision nature of the macromolecules. Decoding of the functional information contained in the molecular structure is achieved via tandem mass spectrometry without recourse to their synthetic history, showing that the sequence information can be read.We submit that the presented photochemical strategy is a viable and advanced concept for coding individual monomer units along a macromolecular chain.
A metrological approach to improve accuracy and reliability of ammonia measurements in ambient air
(2016)
The environmental impacts of ammonia (NH3) in ambient air have become more evident in the recent decades, leading to intensifying research in this field. A number of novel analytical techniques and monitoring instruments have been developed, and the quality and availability of reference gas mixtures used for the calibration of measuring instruments has also increased significantly. However, recent inter-comparison measurements show significant discrepancies, indicating that the majority of the newly developed devices and reference materials require further thorough validation. There is a clear need for more intensive metrological research focusing on quality assurance, intercomparability and validations. MetNH3 (Metrology for ammonia in ambient air) is a three-year project within the framework of the European Metrology Research Programme (EMRP), which aims to bring metrological traceability to ambient ammonia measurements in the 0.5–500 nmol mol−1 amount fraction range. This is addressed by working in three areas: (1) improving accuracy and stability of static and dynamic reference gas mixtures, (2) developing an optical transfer standard and (3) establishing the link between high-accuracy metrological standards and field measurements. In this article we describe the concept, aims and first results of the project.
In this study a metal-matrix-composite with aluminum matrix and Al2O3 particles was investigated with x-ray refraction topography and in-situ tensile loading. It could be observed that after reaching a certain load the specific surface increased steadily. However, the classical radiographs taken for comparison show no damage in the sample.
Preparation of graphene oxide by cyanuric chloride as an effective and non-corrosive oxidizing agent
(2016)
In this work, we report a new method for the synthesis of graphene oxide (GO) using cyanuric chloride as a non-corrosive oxidizing agent.
The mild conditions, simple purification, and scalability of this method are significant advantages over common approaches in which harsh oxidizing agents are used. Moreover, a major drawback with the Hummers' method, the production of toxic gases, is not an issue with this process. This method is a safe and large-scale alternative for the production of GO under mild conditions.
Light damage to selected organic materials in display cases: A study of different light sources
(2016)
The protection of works of art and cultural assets against light-induced aging is vital when planning exhibitions. Newly developed lighting systems render the selection of suitable light sources more difficult, not least in the context of energy–economical systems. This study accordingly examines different lighting systems (fluorescent tubes, halogen lamps, low-voltage metal halide lamps, and LED lamps) in terms of the damage potential they hold for the materials concerned. The changes in color were evaluated using the CIEDE2000 color-difference formula. This study focuses on selected organic materials and shows that changes in color already occur after only a brief exposure time. The color changes induced by the fluorescent tubes were consistently more intense than those induced by the other light sources. The results obtained with the remaining lamps show that the color changes depend more on the material under investigation than on the source used. The changes determined after a relatively short exposure period (five months) vividly demonstrate that exposing sensitive materials to light for longer terms (as is the case during a permanent exhibition) is most definitely a non-viable option.
Molecular machines are a key component in the vision of molecular nanotechnology and have the potential to transport molecular species and cargo on surfaces. The motion of such machines should be triggered remotely, ultimately allowing a large number of molecules to be propelled by a single source, with light being an attractive stimulus. Here, we report upon the photoinduced translation of molecular machines across a surface by characterizing single molecules before and after illumination. Illumination of molecules containing a motor unit results in an enhancement in the diffusion of the molecules. The effect vanishes if an incompatible photon energy is used or if the motor unit is removed from the molecule, revealing that the enhanced motion is due to the presence of the wavelength-sensitive motor in each molecule.
We present the results of a machine learning (ML)- inspired data fusion approach, applied to multi-sensory nondestructive testing (NDT) data. Our dataset consists of Impact-Echo (IE), Ultrasonic Pulse Echo (US) and Ground Penetrating Radar (GPR) measurements collected on large-scale concrete specimens with built–in simulated honeycombing defects. In a previous study we were able to improve the detectability of honeycombs by fusing the information from the three different sensors with the density based clustering algorithm DBSCAN. We demonstrated the advantage of data fusion in reducing the false positives up to 10% compared to the best single sensor, thus, improving the detectability of the defects. The main objective of this contribution is to investigate the generality, i.e. whether the conclusions from one specimen can be adapted to the other. The effectiveness of the proposed approach on a separate full-scale concrete specimen was evaluated.
Sealing and strengthening of the subsoil by grout injection is a major issue in the field of geotechnical engineering. One commonly applied method is jet grouting, which allows creating columns of grouted soil by eroding and mixing the in-situ soil with a thin cement suspension. A general difficulty linked with this method is in predicting the resulting column diameter and its material strength. In this paper, we illustrate the application of a newly developed non-destructive quality assurance tool used to determine the diameter of jet grout columns. This approach incorporates standard crosshole and downhole seismic measurements. To demonstrate its effectiveness, we tested the new approach within two-dimensional finite-difference numerical simulations. Additional field tests showed that this tool is also applicable in real site conditions. For this purpose, three jet grout columns were produced with different process parameters in a depth between 3 and 10 m. The evaluated diameters were within 1 and 1.5 m, slightly deviating from the previously predicted range by the jet grouting contractor. Moreover, we were able to detect the base of the columns at a 10-m depth with no significant difficulties. On the other hand, unsaturated, less compacted sands between the groundwater level and surface considerably affected the seismic data, hence complicating the detection of the top of the columns.
Starting out from Flory`s most probable Distribution concept, correct and incorrect evaluations of SEC measurements are discussed. Using the correct mode, polyesters prepared by irreversible and reversible polycondensation methods were studied. Polyesters of α,ω−alkanediols and isophthalic acid or polyesters of diphenols and sebacic acid were prepared by three different irreversible polyconcensation methods. Formation of cyclic oligo and polyesters was monitored by MALDI-TOF mass spectrometry and dispersities were measured by SEC. The results are compared with the theories of Flory and Odian.
Eqilibrated polyesters were prepared by reversible polycondensation of ethyl 6-hydroxycaproate or by alcohol-initiated ring-opening polymerization of ε-caprolactone. Various catalysts were compared. The influence of dilution and of di- or multifunctional initiators was evaluated. Furthermore, equilibrated polylactides were prepared from L- or meso-lactide at 120, 160 and 180°C. A fast even-odd equilibration was discovered in addition to reversible cyclization and intermolecular transesterification. The influence of these different equilibration mechanisms on the dispersity was investigated. The preparative and theoretical consequences are discussed.
The content of the paper is the assessment of the performance of (conventional) measurement techniques (MTs)with respect to the classification of disperse materials according to the EC recommendation for a definition of nanomaterial. This performance essentially refers to the accurate assessment of the number weighted median of (the constituent) particles. All data and conclusions are based on the analytical study conducted as real-world performance testing.
It comprised different types of MTs (imaging, counting, fractionating, spectroscopic and integral) as well as different types of materials. Beside reference materials with well-defined size distribution the study also included several commercial powders (variation of particle composition, morphology, coating, size range and polydispersity). In order to ensure comparability of measurement results, the participants were guided to use uniform protocols in sample preparation, conducting measurements, data analysis and in reporting results. Corresponding documents have been made public, in order to support the reviewing process of the paper, respectively to ensure the reproducibility of data by other users under the same conditions.
The scientific paper relies on a comprehensive set of revised measurement data reported in uniform templates, completely describes the experimental procedures and discusses the MTs’ performance for selected materials in detail. Even more, the study is summarised and evaluated, which leads to recommendations for the use of MTs within a tiered approach of NM characterisation. In addition, the paper critically examines the factors that may affect the outcome of such a comparison among different MTs.
Scanning Electron Microscopy (SEM) or Transmission Electron Microscopy (TEM) ? This is a question, nowadays discussed in EM labs of research and industry involved in the characterization and metrology of nanoparticles. The Scanning principle is adapted to TEM, the Transmission mode is adapted to Ultra High Resolution SEM. Can modern SEM replace TEM, reach atomic resolution even without Cs corrector or nm lateral resolution for X-ray Spectroscopy (EDX)?
Due to the development of a New Cold Field Emission (NCFE) electron source Hitachi SEMs SU9000 and SU8200 can deliver routinely sub-nm image resolution and EDX mappings at very high count rates and a lateral EDX resolution of a few nm. A TiO2 sample provided by BAM was analysed at 30 kV using low kV STEM – simultaneously with the Through-the-lens (TTL) SE detector, the Bright Field transmission and Dark Field transmission signals. By this method a pixel-precise information of the particle’s surface using SE, its chemical nature using DF-STEM and its crystalline structure using Bright Field signal is given in one 40sec scan. The advantage of this observation mode compared to Ultra Low Voltage imaging is outlined.
The design of bright and functional dye–protein conjugates requires hydrophilic and stable fluorophores with high molar absorption coefficients and high fluorescence quantum yields,which must not be prone to dimerization, as well as conservation of protein function and suppression of protein association. Although many synthetic dyes meet these needs, the influence of dye charge on bioconjugate performance is commonly neglected. This encouraged us to assess the spectroscopic properties, antibody functionality, binding behavior, folding, and association of conjugates of the therapeutic antibodies trastuzumab and cetuximab with the red cyanine dyes S0586, S2381,and 6SIDCC (bearing two, three, and six sulfonate Groups respectively.
Our results demonstrate a negligible effect of dye labeling on antibody folding, yet a strong influence of Label charge and density on antibody isoelectric points and association.Especially 6SIDCC decreased strongly the isoelectric points of both antibodies and their heavy or light chains even at low labeling degrees, thus favoring protein association. Although an increasingly negative dye charge reduces Antigen affinity as shown in a competitive immunoassay, all conjugates still bound to cells overexpressing the target of the respective antibody. Obviously, dyes that cause minimum dimerization with a small number of charged groups are best for conjugate brightness, minimum protein association, and strong target binding. This underlines the need to consider dye Charge for the rational design of conjugates with Optimum performance.
In order to ground the debate on the metrics that apply for VSSA determined by adsorption isotherms and to illustrate the consequences of real bimodality for VSSA screening, a bimodal mixture has been selected for systematic investigations. A sample of BaSO4 fine was spiked with 10% g/g of BaSO4 ultrafine. The ultrafine grade is a clear nanomaterial (NM) according to the size criterion with a median Feretmin of 27 nm and the fine grade is clearly a non-NM with a median Feretmin of 249 nm. Because of the number ratio of 300:1, the mixture has to be a NM according to the size criterion. Three independent BET measurements were performed on the mixture by two different labs and resulted in a mean VSSA of 23 m2/cm3 with a standard deviation of 3.3 m2/cm3, which leads to a dminVSSA of 258 nm, and, therefore, would falsely classify the material as a non-NM. This effect was predicted earlier by calculated examples (Roebben et al. 2014) and demonstrates that mixtures of nano- and non-nano multimodal materials very likely lead to false negative classifications. Moreover, the measured VSSA values for the mixture of 23 m²/cm³ are in excellent accord with the value of 24.6 m²/cm³ predicted from the TEM size distributions of the individual materials according to the model described by JRC (Roebben et al. 2014), but are significantly different from the prediction of 309 m²/cm³ obtained from the same TEM size distribution by a particle number weighted approach (Lecloux 2015). The same is true for a 50% g/g mixture. We conclude that the mass-based VSSA approach (Roebben et al. 2014) is equal to the VSSA that is measurable by adsorption isotherms, such as from standardized BET.
A proposal of an inter-laboratory study (ILC) on determination of size and shape distribution of TiO2 nanoparticles (NPs) by transmission electron microscopy is presented. The anatase NPs synthesized in a controllable fashion within the EU/FP7 project SETNanoMetro can be considered as shape-defined (bipyramidal) and are offered to complete the list of case studies already in progress within ISO/TC229/JWG2. The main points of the measurement procedure are presented as well as a proposed procedure to evaluate the size and shape according to the standard operation procedure already developed within SETNanoMetro is discussed. Potential ILC participants and a plan with next step to be carried out are proposed.
A high-performance fiber Bragg grating-based (FBG) sensor device has been developed for the detection of small magnetic fields. Based on a smart multilayer jacket around the fibre over the physical length of the FBG, magnetic fields generated by rotating machine parts, power generators or power cable can be easily detected, analysed and evaluated. Consequently, this innovative, on-line and non-contact inspection method results in an increase in quality and reliability of high-performing machine parts, devices and cables. The basic physical principle is based on a magnetostrictive multilayer system that strains the high-resolution FBG element in presence of magnetic fields. Subsequently, a fixed relationship between induced magnetic field and wavelength change of the FBG element describes the characteristic sensitivity curve. Intensive tests regarding characterisation of this magnetic field FBG sensor have been carried out and its performance has been evaluated.
High Speed, High Resolution imaging spectrometers based on pnCCDs for XRF and XRD applications
(2016)
For many years pnCCDs have been well known as X-ray detectors for spectroscopic imaging in many fields of science: X-Ray Fluorescence analysis (XRF), X-ray Diffraction (XRD) with light sources in large accelerator facilities as well as with laboratory light sources or with X-rays from celestial sources in X-ray astronomy. A brief introduction in GEXRF (Grazing Emission XRF) measurements with a laboratory laser produced plasma source will be given, PIXE (Particle Induced X-ray Emission) measurements and D2XRF (Double Dispersive X-Ray Fluorescence) and Slicing experiments with pnCCDs coupled to polycapillary optics performed at the BESSY synchrotron will be shown. Energy-dispersive Laue diffraction with ultra-hard X-rays for the analysis of defects in metals will conclude the overview of spectroscopic X-ray imaging measurements in the field of structure and dynamics of matter.
High Speed X-ray Imaging and Spectroscopy with pnCCDs: XRF, XRD and PIXE measurements (and others)
(2016)
For many years pnCCDs have been well known as X-ray detectors for spectroscopic imaging in
many fields of science: X-Ray Fluorescence analysis (XRF), X-ray Diffraction (XRD) with light
sources in large accelerator facilities as well as with laboratory light sources or with X-rays from
celestial sources in X-ray astronomy. A brief introduction in GEXRF (Grazing Emission XRF)
measurements with a laboratory laser produced plasma source will be given, PIXE (Particle Induced
X-ray Emission) measurements and D2XRF (Double Dispersive X-Ray Fluorescence) and Slicing
experiments with pnCCDs coupled to polycapillary optics performed at the BESSY synchrotron will
be shown. Energy-dispersive Laue diffraction with ultra-hard X-rays for the analysis of defects
in metals will conclude the overview of spectroscopic X-ray imaging measurements in the field of
structure and dynamics of matter.
Nowadays, superplasticizers (SPs) are widely used to increase fluidity and reduce water content in concrete; thus, allowing better workability for final applications. The present study will focus on the hydration effect using comb shape polycarboxylates (PCEs), which are known to allow a very low water/cement ratio (w/c of 0.20) or less.Optical methods have been successfully used for the analysis and monitoring of the interactions between a broad variety of nanoscale and molecular systems like nanoparticles of various chemical composition and different types of organic ligands or biomolecules.This encouraged us to assess the potential of these methods, and particularly fluorescence, for the investigation of the interactions that occur at the interface between hydrate surfaces of cement particles and PCE at a very early stage of concrete formation and to differentiate between the impact of PCE’s molecular structures on such interactions.
Today, chemical admixtures like superplasticisers and stabilising agents are extremely important for modern concrete technology. These agents have meanwhile become common practice in concrete technology, but the understanding within the entire system lags far behind their application. The macroscopic rheology of concrete in the presence of superplasticizers strongly depends upon effects on a much smaller scale such as the hydration of the cement, the adsorption of superplasticizers, and the pore solution chemistry.
Using channeling-enhanced energy-dispersive X-ray spectroscopy (EDX), we demonstrate polarity sensitive orientation determination of a non-centrosymmetric crystal in the scanning electron microscope. The authors observe a characteristic asymmetry in the channeling-enhanced, angle-dependent EDX data of a GaAs sample, which is in good agreement to simulations using the dynamical theory of diffraction for the incident electron beam. This allows us to assign the orientation of the GaAs crystal according to the non-centrosymmetric point group. The method shown here overcomes the limitation of a reduced point-group sensitivity of electron backscatter diffraction Patterns and electron channeling patterns for crystalline phases that contain atoms of approximately equal electron scattering cross sections.
Nondestructive flaw detection in polymeric materials is important but difficult to achieve. In this research, the application of magnetite nanoparticles (MNPs) in nondestructive flaw detection is studied and realized, to the best of our knowledge, for the first time. Superparamagnetic and highly magnetic (up to 63 emu/g) magnetite core-shell nanoparticles are prepared by grafting bromo-end group-functionalized poly(glycidyl methacrylate) (Br-PGMA) onto surface-modified Fe3O4 NPs. These Fe3O4-PGMA NPs are blended into bisphenol A diglycidylether (BADGE) based epoxy to form homogeneously distributed magnetic epoxy nanocomposites (MENCs) after curing. The core Fe3O4 of the Fe3O4-PGMA NPs endows the MENCs with magnetic property, which is crucial for nondestructive flaw detection of the materials, while the shell PGMA promotes colloidal stability and prevents NP aggregation during curing. The eddy current testing (ET) technique is firstly applied to detect flaws in the MENCs. Through the brightness contrast of the ET image, surficial and sub-surficial flaws in MENCs can be detected, even for MENCs with low content of Fe3O4-PGMA NPs (1 wt %). The incorporation of Fe3O4-PGMA NPs can be easily extended to other polymer and polymer-based composite systems and opens a new and very promising pathway toward MNP-based nondestructive flaw detection in polymeric materials.
The TiO2 material selected for the present inter-laboratory comparison (ILC) was the bipyramidal anatase UT001 batch synthesized hydrothermally by University of Turin in the frame of the EU/FP7 Project SETNanoMetro and carefully prepared on TEM grids by BAM to be distributed to the ILC participants. A clear measurement protocol including data analysis and reporting (including an xls reporting template) has been also prepared by BAM. 14 of 18 participants have measured and reported results which have been already checked by BAM as being conform to the agreed protocol. After receiving the last results (of 4 participants) the ILC data evaluation will be carried out by BAM in line with agreed ISO/TC229 procedures as for the other case sudies.
IND15 JRP SurfChem: Traceable quantitative surface chemical analysis for industrial applications
(2016)
The SurfChem project has made a significant contribution to traceable quantitative surface chemical analysis for industrial applications by delivering new certified reference materials and test samples for specific technical applications. Regular performance tests of instruments, metrological methodology for the detection of (bio)organic surface species, ambient and non-destructive surface chemical analysis for in-line process control and new in situ characterisation techniques of catalytically active surfaces have been achieved.
Modifying or controlling surface chemistry is important in new product development, quality control and research. This is particularly true where functionality of surfaces, thin films and interfaces are key to the application, such as organic solar cells and devices for medical diagnostics. Surface chemical analysis aims to provide quantitative elemental, chemical state and functional group information from the surface of materials, but requires comparable test data and improved measurement traceability.
Measuring organic layers
(2016)
Many innovative products - from touchscreens to solar panels to pharmaceuticals – utilise multiple organic layers to create complex functionality. New techniques have been developed to remove and measure layers individually enabling improved product development and assisting with quality assurance. However, manufacturers cannot be certain of the depth of layer being removed and new reference materials for these techniques are needed to increase uptake, and remove a major barrier to innovation.
Materials and chemical producers require detailed knowledge of surface chemistry for research into new products. One way to understand a surface without damaging it is to bombard it with an electron beam, causing its atoms to emit characteristic X-rays enabling identification. The measurement of these must be precise as many elements emissions are close in energy – traceable reference materials will ensure instruments using this technique are stable and accurate.
A method is proposed to determine the effective detector area for energy-dispersive X-ray spectrometers (EDS). Nowadays, detectors are available for a wide range of nominal areas ranging from 10 up to 150mm2. However, it remains in most cases unknown whether this nominal area coincides with the “net active sensor area” that should be given according to the related standard ISO 15632, or with any other area of the detector device. Moreover, the specific geometry of EDS installation may further reduce a given detector area. The proposed method can be applied to most scanning electron microscope/EDS configurations. The basic idea consists in a comparison of the measured count rate with the count rate resulting from known X-ray yields of copper, titanium, or silicon. The method was successfully tested on three detectors with known effective area and applied further to seven spectrometers from different manufacturers. In most cases the method gave an effective area smaller than the area given in the detector description.
Ultrasonic imaging systems usually require an array of ultrasonic transducers for data acquisition on a wide area on top of an object under investigation. The goal of an imaging algorithm is the use of reflected ultrasound data to form a recognizable image. Conventional algorithms like SAFT are based on an inverse Huygens' principle and need therefore a dense measurement grid. This requires a big effort in data capturing. For simple and inexpensive measurement different strategies of imaging with reduced amount of data and examples with a manual scanning device on concrete elements are presented.
The investigation of cultural assets often deals with the question of provenance, dating, or attribution to artists or workshops. The analysis of physical properties and chemical composition generates important data for answering cultural-historical questions that cannot be solved by stylistic and art-historical methods alone. Starting from some wooden painted architectural elements from Kocho and one from Bezeklik (III 8592), this paper aims to give some insights into the multi-instrumental approach to the analysis of cultural artefacts.
The Color X-ray Camera CXC or SLcam® is an energy-resolving X-ray camera capable of energy- and space-resolved measurements. It consists of a high-speed CCD detector coupled to a polycapil-lary optic that conducts the X-ray photons from the probe to distinct pixels onto the detector.
The camera is capable of fast acquisition of spatially and energy resolved fluorescence images. A dedicated software enables the acquisition and the online processing of the spectral data for all 69696 pixels, leading to a real-time visualization of the elements distribution in a sample. It was developed in a joint project with BAM, IFG Berlin and PN Sensors.
In this contribution we will mainly discuss the use of the CXC at our beamline, the BAMline at BESSY II and imaging applications of the CXC from different areas, like biology and archaeometry. Additionally new developments for the use of the detector without optics, like wavelength dispersive detection or 1shot-XANES, will be presented.
Gold mosaics, made from gold and glass, are one of the best expressions of Late Antique Byzantine and Early Islamic art. The gold alloys, whose composition seems to indicate that gold coins were re-used to fabricate the tesserae, can be used to provide information on the mosaics chronology. Monetary Byzantine gold is in fact characterized by the presence of Pt, which contents in the gold alloy change over time, but Pt must be measured in 0.2-0.4 µm thickness gold leaves that were beaten to be sandwiched between two glass layers.
To analyze this samples the D²XRF set-up at the BAMline at the BESSY synchrotron in Berlin was used. The combination of a crystal for wavelength dispersion and an energy resolving single photon counting pnCCD allows the realization of this very simple wavelength dispersive detection system. With this system an MDL of 1 μg/g for the determination of Pt in Au under optimal conditions can be reached.
Gold leaf tesserae from nine archaeological sites, covering the period that goes from the 5th c. to the 8th c., were analyzed. The presence of Pt in the majority of the samples confirmed the re-use of coins. The Pt contents separate the samples in three groups, one of which having the same chemical characteristics as the Byzantine gold could be compared to dated coins for chronology. The higher Pt contents for one of other groups suggest
Tattooing practice is adopted worldwide and represents a socio-cultural phenomenon, but the injection into the skin of coloring agents, such as metals might pose a serious health problem. Tattoo ink compounds are in general not officially controlled. Moreover, the origins as well as the chemical and toxicological specifications of these coloring agents are hardly known by the producers, the tattooists and by the consumers. In this view, the aim of this study was to characterize the metal composition of tattoo inks available in the market and to draw attention to the associated risk for human health.
A set of tattoo inks from the brand Kuro Sumi was analyzed by means of Synchrotron-based X-ray Fluorescence spectrometry (Sy-XRF) at BAMline @ BESSY II and Raman Spectroscopy using the XploRA confocal Raman microscope (785 nm laser) at the LIBPhys-UNL. Carbon black, rutile, phtalo blue, phtalo green, helizarin red, helizarin yellow and dioxazine violet were respectively identified in black, white, blue, green, red, yellow and violet inks. However, a wide range of transition and heavy metals, potentially hazardous was revealed by Sy-XRF. A semi-quantitative evaluation has revealed, in some inks, amounts of Cr, Cu, Zn and Pb higher than the allowed according to the resolution adopted by the Council of Europe on the safety of tattoos and permanent make-up.
Integrating fluorescent probes with sensing matrices presents a major challenge because usually, when confined in a rather rigid matrix, fluorophores tend to behave completely different than for instance in the molecular state in solution. The lecture reviews the major strategies that have been devised recently to circumvent such issues with special focus on the works carried out in this field by BAM’s Chemical and Optical Sensing Division. Moreover, it will be shown that by using certain strategies not only can the response behavior be retained but synergistic effects can even endow the hybrid with a much better performance than the probe molecule alone.
The newly developed EXAFS set-up comprises both time- and spatially-resolved EXAFS information simultaneously in a single-shot. This facile, stable and scanningless set-up was tested at the BAMline @ BESSY-II (Berlin, Germany). The primary broadband beam is generated by a filter/X-ray-mirror combination (bandpass). The transmitted beam through the sample is diffracted by a convexly bent Si (111) crystal, producing a divergent beam. This, in turn, is collected by an area sensitive detector based on a CCD camera, in a theta - 2 theta geometry.
The first in situ measurements were successfully carried out and hereby presented. The case-study involved a well known reaction, in which structural changes are induced over time, and continuously measured. We were able to track structural changes within a 1s time resolution.
Toxic metals in tattoo inks
(2016)
Tattooing practice is adopted worldwide and represents a socio-cultural phenomenon, but the injection into the skin of coloring agents, such as metals might pose a serious health problem. Tattoo ink compounds are in general not officially controlled. Moreover, the origins as well as the chemical and toxicological specifications of these coloring agents are hardly known by the producers, the tattooists and by the consumers. In this view, the aim of this study was to characterize the metal composition of tattoo inks available in the market and to draw attention to the associated risk for human health.
A set of tattoo inks from the brand Kuro Sumi was analyzed by means of Synchrotron-based X-ray Fluorescence spectrometry (Sy-XRF) at BAMline @ BESSY II and Raman Spectroscopy using the XploRA confocal Raman microscope (785 nm laser). Carbon black, rutile, phtalo blue, phtalo green, helizarin red, helizarin yellow and dioxazine violet were respectively identified in black, white, blue, green, red, yellow and violet inks. However, a wide range of transition and heavy metals, potentially hazardous was revealed by Sy-XRF. A semi-quantitative evaluation has revealed, in some inks, amounts of Cr, Cu, Zn and Pb higher than the allowed according to the resolution adopted by the Council of Europe on the safety of tattoos and permanent make-up (PMU.
Multiplexed bead-based array formats play an increasingly important role in analytical laboratories. Due to the high surface-to-volume ratio, fast reaction kinetics and modular assay design, these sensor formats are applied in clinical diagnostic, drug development and classical biosensors with great success.
As the spherical platform, researchers utilize micron sized particles made from polymeric or silica material. Such beads are commercially available from vendors such as BD or Luminex. However, we have encountered several problematic issues which accompany these platforms: first, bigger sized beads, which are required for particle handling reasons, are difficult to prepare with high monodispersity - a key requirement for cytometric application. Second, plain beads, made from either polymer or silica, have each several disadvantages such as inferior scattering properties in case of silica or limited flexibility for coupling strategies in the case of latex beads.
In order to overcome this problem, we have developed a versatile core-shell (CS) platform which consists of a polymeric core with a structurally controlled silica shell. In our approach, the core building block can be easily prepared with high yields and high monodispersity in a dispersion polymerization from approximately 500 nm to 1.3 µm. Then, silica is coated in a classical sol-gel process to protect the core with a stable yet modifiable surface (see SEM image in Figure 1, platform). Here, we combine ideal scattering properties and easy preparation of the polymeric core with the chemical flexibility of a silica surface. Moreover, the additional shell domain adds density to the composite, which makes particle handling feasible also for nanometer sized beads.
In this contribution we present proof-of-principle results of competitive immunoassays with fluorescence detection using our CS beads – each performed in mix-and-read fashion without washing steps. All sizes are applicable in cytometric read-out which and can be used for size encoding (see Set 1 to 3 in Figure 1, size encoding). However, further multiplexing for a set of at least 20 parameters can be achieved by swelling hydrophobic dyes into the core. To the same time, precise tuning of the surface with mixed silane layers allowed us to improve the selectivity towards small molecules in competitive immunoassays significantly (see example in Figure 1, Application). We believe that our platform allows researchers to gain access to superior assay performance in combination with a low-threshold approach for the synthesis of the spherical platform.
Since more than 20 years, optical spectroscopic techniques, in particular fluorescence-based methods, are on the rise in many different areas of chemical and biochemical analysis, with no end being in sight.1,2 Advances in miniaturization and remote applications on one hand and ground-breaking developments in microscopy and laser-based high-throughput instrumentation on the other hand have fuelled these developments substantially.3,4 At the core of utmost of these applications however is not only the instrument, but a small entity that is able to absorb and emit photons and thus to report on the actual (bio)chemistry that is going on in a particular sample of interest.5,6 Besides intense research on various types of luminescent particles (e.g., quantum dots and carbon dots) and proteins, dye chemistry has thus seen its revival and the number of publications dealing with the design, synthesis and application of new fluorescent dyes as probes, stains, labels or indicators is still continuing to grow.
Among the various classes of dyes available as bright fluorophores for a wavelength range that is compatible with many (bio)analytical applications and the respective instrumentation, in particular pyrrolic dyes that do not belong to the classical porphyrins or phthalocyanines have received strong attention recently. Starting perhaps with the revival of the traditional boron-dipyrromethene laser dye ca. 15 years ago,7 these so-called BODIPYs have developed into a colourful spectrum of different derivatives.8 However, the interest in expanding the range of pyrrole-containing π-systems beyond BODIPYs has also constantly increased and has brought about several other pyrrole-based ring systems such as diketopyrrolopyrroles9 or dipyrrolonaphthyridinediones which possess a favourable brightness and other interesting properties. The present contribution will give a critical overview of the field, pinpointing advantages and prospects as well as discussing potential aspects of improvement with an emphasis on the chemical sensing and the longer wavelength range.
Macrocycle-containing fluorescent probes continue to be one of the most popular classes of indicator molecules for the sensitive optical detection of ionic inorganic analytes, in particular metal ions, since the first integration of crown ether building blocks into chromophoric π systems more than 30 years ago. However, whereas a large multitude of such probes have been described for operation in organic or mixed aqueous environments, the step to realistic analytical media such as water samples, aqueous food extracts or body fluids is still scarce. On one hand, this is due to considerably low complex stability constants for instance for alkali and alkaline-earth metal ions. On the other hand, many classes of organic dyes that show favourable spectroscopic properties and ion-induced responses in organic solvents are not soluble in neat aqueous media and/or exhibit only significantly quenched fluorescence, even if transition metal ions are binding strongly to the receptor unit. A way to circumvent such problems in a rather simple manner is the steric incorporation of fluorescent probes into mesoporous silica nanomaterials. The local polarity in such pores, whether nascent or modified appropriately with functional silanes, resembles much more a quasi-organic environment while at the same time allowing for free diffusion of water and its cargo.
Two examples of powerful hybrid signalling systems will be presented, utilizing charge transfer-type indicator molecules that show inferior sensing properties in their molecular state. One example discusses mercury(II) determination over an extended concentration range and the other discusses silver(I) and mercury(II) discrimination simply on the basis of photophysical effects retained in the hybrid materials.
Synchrotron-radiation enables the adjustment of the XPS information depth and, thus, the visualization of depth profiles of the elemental composition within the first 10 nm of a surface. This project deals with the analysis of core-shell nanoparticles. It constitutes first steps towards a valid methodology for studying the surface chemistry of nanoparticles in a quantitative and accurate manner.
A collisional-dominated model of a laser induced plasma will be presented which includes the coupled Navier-Stokes, state, radiative transfer, and material transport equations and incorporates plasma chemistry through the equilibrium approach based on the use of atomic and molecular partition functions. Simple chemical systems are modeled including ablation of Si, C, SiC, CaCl2 in N2 or Ar atmospheres with the formation of molecules N2, C2, Si2, CN, Cl2, SiN, SiC, CaCl, CaCl2 and their corresponding positive and negative ions. The model is used to study evolution of number densities of atomic and molecular species in the expanding plasma plume. The distribution is compared to experimental observations obtained by optical imaging and tomography. The model and experiment serve to elucidate mechanisms of molecular formation in LIPs, the topic which has recently received much attention in the LIBS community.
A collisional-dominated model of a laser induced plasma will be presented which includes the coupled Navier-Stokes, state, radiative transfer, and material transport equations and incorporates plasma chemistry through the equilibrium approach based on the use of atomic and molecular partition functions. Simple chemical systems are modeled including ablation of Si, C, SiC, CaCl2 in N2 or Ar atmospheres with the formation of molecules N2, C2, Si2, CN, Cl2, SiN, SiC, CaCl, CaCl2 and their corresponding positive and negative ions1,2. The initial conditions are specially chosen to emulate the plasma state on the onset of expansion just after the laser pulse had ended.
The model is used to study evolution of number densities of atomic and molecular species in the expanding plasma plume. The distribution is compared to experimental observations obtained by optical imaging and tomography. The model and experiment serve to elucidate mechanisms of molecular formation in LIPs, the topic which has recently received much attention in the LIBS community.
Two topics will be addressed: (1) calibration-free LIBS based on Monte Carlo spectral optimization and (2) insight into the possibility of simultaneous elemental and molecular analysis by LIBS. Both topics heavily rely on modeling of laser induced plasma and are closely connected to experiment. In Monte Carlo LIBS (MC LIBS), concentrations are found by fitting model-generated synthetic spectra to experimental spectra. The model of a static uniform isothermal plasma in local thermodynamic equilibrium is employed. Many configurations of plasma parameters and their corresponding spectra are simultaneously generated using a graphic processing unit (GPU). Using the GPU allows for the reduction of computational time down to several minutes for one experimental spectrum that presents the significant progress in comparison with earlier versions of MC LIBS. The method is tested by analyzing industrial oxides containing various concentrations of CaO, Fe2O3, MgO, and TiO2. The agreement within several percent between found and certified concentrations is achieved. Next, a newly developed collisional-dominated model of a laser induced plasma is introduced. The model includes the coupled Navier-Stokes, state, radiative transfer, and material transport equations and incorporates plasma chemistry through the equilibrium approach based on the use of atomic and molecular partition functions. Simple chemical systems are modeled including ablation of Si and C in N2 and Ar atmospheres.The model is used to study evolution of number densities of atomic and molecular species in the expanding plasma plume. The distribution is compared to experimental observations obtained by optical imaging and tomography. To further verify the model, dynamic plasma
The equation of state for plasmas containing negative atomic and molecular ions (anions) is modeled. The model is based on the assumption that all ionization processes and chemical reactions are at local thermal equilibrium and the Coulomb interaction in the plasma is described by the Debye–Hu¨ckel theory. In particular, the equation of state is obtained for plasmas containing the elements Ca, Cl, C, Si, N, and Ar. The equilibrium reaction constants are calculated using the latest experimental and ab initio data of spectroscopic constants for the molecules CaCl2, CaCl, Cl2, N2, C2, Si2 , CN, SiN, SiC, and their positive and negative ions. The model is applied to laserinduced plasmas (LIPs) by including the equation of state into a fluid dynamic numerical model based on the Navier–Stokes equations describing an expansion of LIP plumes into an ambient gas as a reactive viscous flow with radiative losses. In particular, the formation of anions Cl-, C-, Si-, Cl2, Si2, C2 , CN-, SiC-, and SiN- in LIPs is investigated in detail.
Purity statements of high purity materials serving as primary standards by GDMS.
Primary standards are materials known for their total purity and therefore appropriate to realise the link with the International System of Units (SI). The realisation and dissemination of primary standards is of fundamental importance for comparability of measurement results through traceability in all fields of chemical analysis.
To serve as a primary standard for element determination the total purity of a high purity material needs to be measured. In order to achieve a sufficiently small uncertainty (i.e. < 0.01%) this involves determining all possible impurity contributions and to subtract their sum from the ideal purity of 100%.
GD-MS has the potential to reduce the effort for purity determination, as a fast sensitive multi-element analysis without extensive sample preparation. Similar to other solid sampling techniques, glow discharge
requires calibration link the measured signal and the content of the impurities in the matrix.
The use of the concept Relative Sensitivity Factors (RSFs) provides good approximations especially for high purity materials. However, it only works with a wide uncertainty of the results.
The preparation of synthetic pressed powder samples by different modifications of liquid and powder doping used for the determination of both metallic and none-metallic impurities are described. Efficient determination of metallic impurities by GD-MS via differential and absolute measurements with a significantly reduced target uncertainty of 20 % for absolute measurements using liquid doped pressed powder calibration could be achieved. The determination of impurities has been evaluated by independent analytical methods such as HR-ICP-MS, ETAAS; CGHE and combustion analysis
Under the assumption of local thermal equilibrium, a numerical algorithm is proposed to find the equation of state for laser-induced plasmas (LIPs) in which chemical reactions are permitted in addition to ionization processes. The Coulomb interaction in plasma is accounted for by the Debye–Hückel method. The algorithm is used to calculate the equation of state for LIPs containing carbon, silicon, calcium, chlorine, nitrogen, and argon. The equilibrium reaction constants are calculated using the latest experimental and ab initio data of spectroscopic constants for the molecules N2, C2, Si2, CN, Cl2, SiN, SiC, CaCl, CaCl2 and their positive and (if existed) negative ions. The algorithm is incorporated into a fluid dynamic numerical model based on the Navier–Stokes equations describing an expansion of LIP plumes into an ambient gas. The dynamics of LIP plumes obtained by the ablation of SiC, CaCl2, solid silicon, or solid carbon in an ambient gas containing N2 and Ar is simulated to study formation of molecules and molecular ions. A particular attention is paid to formation of anions Cl−, Cl2−, Si2−, C2−, CN−, and SiN− in LIPs.
We report on the in situ investigation of mechanochemical syntheses of metal phosphonates. The metal phosphonates are formed in milling reactions starting from a metal acetate and a phosphonic acid. The conversions are observed by synchrotron PXRD and Raman spectroscopy to shed light on the reaction mechanisms including possible intermediates.
Fire-gilding or amalgam gilding is a historical technique for the gilding of objects. The object to be gilded is coated with an amalgam (a solution of gold (Au) in mercury (Hg)). By heating, the largest part of the Hg is subsequently evaporated and there remains a gold layer, containing still detectable amounts of Hg.
The information on the used gilding technique might be crucial for the conservation and preservation of archaeological objects. Therefore, the main objective of this work is the detailed understanding of the behaviour of Hg under conditions of fire gilding. I.e. the understanding of the diffusion and evaporating behaviour of Hg, depending on parameters like substrate material (silver, copper, bronze, brass...), heating temperature and duration, and the resulting Hg depth profiles under these conditions. Secondary objective is the establishment of a measurement protocol for the unambiguous identification of different types of gilding, based solely on non-destructive methods, which can be applied to historical samples.
In a first step, fire-gilded samples have been prepared on Cu and Ag sheet metal, respectively. Some of the gildings were produced by a professional goldsmith; another set of samples was produced under laboratory conditions. These samples have been examined with NAA (neutron activation analysis) and SR-XRF (synchrotron radiation induced X-ray fluorescence). First results of these measurements will be presented and discussed.
Wilson´s disease (WD) is a rare genetic disorder of the copper metabolism, causing the accumulation of copper in different organs, including the liver, the central nervous system and cornea. This way, WD initiates manifold hepatic, neurological or psychiatric symptoms. To learn about the elemental distribution and present species in WD, liver samples were analyzed by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), micro X-ray fluorescence (μXRF) and X-ray absorption near edge structure spectroscopy (XANES).
Within this work, LA-ICP-MS was applied to study the distribution of copper and iron in human liver samples, which were collected by a liver biopsy of WD and control patients within a medical investigation. The analysis by LA-ICP-MS was performed with a 213 nm Nd:YAG laser using a spatial resolution of 10 μm and a scan rate of 20 μm/s. In a next step, copper and iron were quantified by LA-ICP-MS using homemade matrix-matched standards made of gelatin. Results showed an inhomogeneous copper and iron distribution in human liver with hotspots up to several thousand micrograms per gram liver within the hepatocytes.
Additionally, results for the elemental distribution in WD were validated by means of synchrotron radiation-based μXRF with a beam size of 4 μm at the BAMline at BESSYII (Helmholtz-Zentrum Berlin). Furthermore, XANES was performed to identify the present oxidation states of copper in WD, indicating a mixture of copper(I) and copper(II) within the liver tissue.
In the contemporary medicine, rhodanine staining is routinely used to determine the copper distribution in liver tissues. Nevertheless, this method does not provide results with a high sensitivity in comparison to LA-ICP-MS. Therefore, the presented LA-ICP-MS method offers a new possible diagnostic tool. These results may also contribute to a better understanding of Wilson´s disease and its development.
Fire-gilding or amalgam gilding is a historical technique for the gilding of objects. The object to be gilded is coated with an amalgam (a solution of gold (Au) in mercury (Hg)). By heating, the largest part of the Hg is subsequently evaporated and there remains a gold layer, containing still detectable amounts of Hg.
The information on the used gilding technique might be crucial for the conservation and preservation of archaeological objects. Therefore, the main objective of this work is the detailed understanding of the behaviour of Hg under conditions of fire gilding. I.e. the understanding of the diffusion and evaporating behaviour of Hg, depending on parameters like substrate material (silver, copper, bronze, brass...), heating temperature and duration, and the resulting Hg depth profiles under these conditions. Secondary objective is the establishment of a measurement protocol for the unambiguous identification of different types of gilding, based solely on non-destructive methods, which can be applied to historical samples.
In a first step, fire-gilded samples have been prepared on Cu and Ag sheet metal, respectively. Some of the gildings were produced by a professional goldsmith; another set of samples was produced under laboratory conditions. These samples have been examined with NAA (neutron activation analysis) and SR-XRF (synchrotron radiation induced X-ray fluorescence). First results of these measurements will be presented and discussed.
Zn is known to be located in the reactive centers of various enzymes, which play a major role in the mineralization process at sites where new bone formation occurs. In addition, elevated Zn levels are supposed to increase the proliferation rate of osteoblasts [1] and may lead to a stimulation of bone formation in vitro and in vivo [2]. Consequently, Zn seems to play an essential role in bone formation and mineralization through various pathways. We thus expected Zn levels to be altered at sites of extensive bone formation like in the case of fracture healing.
We measured the same areas on human bone samples with both a scanning confocal synchrotron radiation induced micro X-ray fluorescence (SR-μXRF) at the FLUO beamline (ANKA) and a full-field Color X-ray Camera at the BAMline (Bessy II) setup in order to find the ideal SR-μXRF imaging method to investigate trace element distributions in bone samples. As zinc is a trace element of special interest in bone, the setups were optimized for Zn detection. The setups were compared concerning count rate, required measurement time and resolution. We could show that the ideal method is depending on the element of interest. While for Ca (a major constituent of the bone with a low energy of 3.69keV for K) the Color X-ray Camera provided us with a higher resolution in the plane, for Zn (a trace element in bone) only the confocal SR-μXRF was able to sufficiently image the distribution.
Biopsies of healing osteoporotic fractures (Vertebral compression fractures (VCFs)) were investigated in regard to their Zn distribution. The samples were measured with a confocal SR-μXRF setup with a 10 μm x 15 μm resolution at the FLUO beamline at ANKA. As we found increased Zn levels, which seemed to be accumulated in narrow structures between bone packages we also investigated thin cuts (4 μm thick) of two sample areas with a higher resolution of 1 μm x 1 μm (monochromatic beam with E= 17 keV) at B16 at Diamond SR facility.
We will present the advantages and disadvantages of all three SR-μXRF setups (ANKA FLUO beamline, Bessy II BAMline, and Diamond B16) for imaging elemental distributions in bone with a focus on Zn. We will also show the distribution of Zn in healing VCFs.
Airborne particulate matter is an issue of growing concern in industrialized countries. Particles with diameters of less than 10 μm (especially those smaller than 2.5 μm) can enter the human respiratory system and contribute to various diseases depending on their chemical composition and the chemical bonding state, in which elements are present. This chemical speciation can be obtained using X-ray absorption near-edge structure analysis (XANES), which requires a tunable excitation source and therefore has to be carried out at synchrotron facilities. Our special interest lies on the analysis of indoor airborne particulate matter, as particle composition and health effects of outdoor particles have been studied abundantly. For this work, samples were collected in various office rooms in the Atominstitut (ATI) building.
The BAMline at BESSYII features a double-multilayer monochromator (DMM) and a double-crystal monochromator (DCM). The DCM offers an energy resolution E/ΔE of around 103, which makes it suitable for XANES applications. The ATI SR-TXRF vacuum chamber, formerly located at HASYLAB, Beamline L, is now available at the BAMline. The chamber offers a sample changer for up to 8 quartz reflectors and a 30 mm² silicon drift detector (SDD) was used. Aerosol samples were produced using a modified three-stage Dekati™ impactor. For this work, only the coarse (2.5 to 10 μm) and the fine particle fraction (1 to 2.5 μm), were of interest. XANES results of Cr, Cu and Zn will be presented on this poster.
The X-ray Fluorescence beamline at ELETTRA operates in partnership with the IAEA an ultra-high vacuum instrument with a 7-axis manipulator suitable for a variety of X-ray analytical techniques, such as grazing incidence and total reflection X-ray fluorescence analysis (GI-XRF and TXRF), X-ray reflectometry (XRR) and XANES. Samples were produced using a four-stage Sioutas Personal Cascade Impactor. With this impactor, it is possible to produce size-fractionated samples down to the sub-μm range (Stages: A > 2.5 μm, B 1 to 2.5 μm, C 0.5 to 1 μm and D 0.25 to 0.5 μm). Direct sampling was performed on siliconized 25 mm Si wafers suitable for TXRF. Cu-K edge SR-TXRF-XANES analysis was carried out for samples of all impactor stages. Results of these experiments will be shown.
Wilson´s disease, a rare genetic disorder of the copper metabolism, causes the copper accumulation in various organs, leading to manifold hepatic, neurological and psychiatric symptoms. To study the elemental distribution, human Wilson´s disease liver samples were analyzed by means of LA-ICP-MS. Results demonstrated an inhomogeneous copper and iron distribution in human liver with hotspots of very high intensities. Both elements were quantified by an external calibration using matrix-matched standards made of gelatin, showing concentrations up to several thousand micrograms per gram. Additionally, results were validated by means of synchrotron radiation based μXRF at the BAMline at BESSYII (Helmholtz-Zentrum Berlin).
Airborne particulate matter is an issue of growing concern in industrialized countries.
Particles with diameters of less than 10 μm, in particular those with less 2.5 μm, are of special
concern, as they can enter the human lungs and contribute to various cardiovascular and
respiratory diseases. As the composition and health effects of airborne particles in urban, rural
and industrial outdoor air has been studied abundantly, our focus lies on the analysis of
airborne particle samples collected indoors, which may also have a significant effect on
human health, depending on the chemical composition of the particles and the chemical
bonding state, in which elements are present. This chemical speciation can be obtained using
X-ray absorption near edge structure (XANES) analysis, which requires a tunable excitation
source and therefore has to be carried out at synchrotron facilities. For this work, samples
were collected in office rooms of the Atominstitut building.
The BAMline at BESSYII, Berlin, features a double-multilayer monochromator (DMM) and a
double-crystal monochromator (DCM). The DCM offers an energy resolution E/ΔE of around
103, which makes it suitable for X-ray absorption fine structure (XAFS) applications. The
Atominstitut SR-TXRF vacuum chamber, formerly located at HASYLAB, Beamline L, is
now available at the BAMline. The chamber offers a sample changer for up to 8 quartz
carriers suitable for total reflection X-ray fluorescence analysis (TXRF) and was equipped
with a 30 mm² silicon drift detector (SDD). Aerosol samples were produced using a modified
three-stage Dekati™ impactor. For this work, only the coarse (2.5 to 10 μm, Stage 2) and the
fine particle fraction (1 to 2.5 μm, Stage 3), were of interest. XANES analysis was performed
for the elements Cr, Cu and Zn. Oxidation states of these 3 elements will be presented.
The X-ray Fluorescence beamline at ELETTRA operates in partnership with the IAEA an
ultra-high vacuum instrument with a 7-axis manipulator suitable for a variety of X-ray
analytical techniques, such as grazing incidence X-ray fluorescence analysis (GI-XRF),
TXRF, X-ray reflectometry (XRR) and XANES. Samples were produced using a four-stage
Sioutas Personal Cascade Impactor. With this impactor, it is possible to produce sizefractionated
samples down to the sub-μm range (Stages: A > 2.5 μm, B 1 to 2.5 μm, C 0.5 to
1 μm and D 0.25 to 0.5 μm). Direct sampling was performed on siliconized 25 mm Si wafers
suitable for TXRF. Cu-K edge SR-TXRF-XANES analysis was carried out for samples of all
impactor stages. Results of these experiments will be shown.
The physico-chemical characteristics of TiO2 coatings can greatly influence their final performance. In SETNanoMetro, different deposition procedures are being set for applying films of TiO2 NPs with defined and homogenous thickness on supports of interest for the applications studied in the project. The selected substrates are the following: (i) Silica glasses for photocatalytic measurements, (ii) Ti-alloys for orthopedic and/or dental prostheses, and for cell cultures, and (iii) Conductive glasses (e.g. Fluorine doped Tin Oxide, FTO) for dye-sensitized solar cells. From the different film deposition procedures studied within the project Self-assembly of TiO2 NPs in multiple layers was selected. For this, surface modification of the substrate and of TiO2 nanoparticles (NPs) with e.g. silane coupling agents is a prerequisite. First attempts to prepare the self-assembled coating on the functionalized glass substrates seem to indicate that the functionalized NPs adhere to the substrates, even if the final coatings were not homogenous and presented agglomerates. ToF-SIMS results support this outcome.
In order to use the layer-by-layer deposition technique for the formation of TiO2 films by controlled self-assembly of the TiO2 NPs, the proper complementary moieties for the functionalization of the NPs were chosen. A first set of NPs has been produced by reaction with (3-aminopropyl)phosphonic acid (APPA) in order to functionalize the surface with free amino-groups. Then, the complementary NP set can be obtained from an aliquot of the first one, through the conversion of free surface amino-groups to aldehydes by reaction with glutaraldehyde. A proper approach for the functionalization of two types of TiO2, commercial P25 (Evonik) and SETNanoMetro-sample labelled UT001, with APPA was developed. A second set of NPs consisting of three types of TiO2 NPs, P25 and SETNanoMetro NPs (TiO2 NPs with high specific surface area > 150 m2/g and TiO2 NPs with low size < 20 nm) was functionalized with (3-aminopropyl)triethoxysilane (APTS). As for the previous set of NPs, the complementary NP set was obtained through the conversion of free surface amino-groups to aldehydes by reaction with glutaraldehyde. EDX, AES and ToF-SIMS spectra were collected and analyzed to demonstrate the presence of the surface functionalization of the different types of TiO2 NPs.
H2Sense - Cost-effective and reliable Hydrogen Sensors for Facilitating the Safe Use of Hydrogen
(2016)
The H2SENSE (Cost-effective and reliable hydrogen sensors for facilitating the safe use of hydrogen) project promoted hydrogen primarily, but not exclusively, for its use as an alternative fuel. It brought together different stakeholders including sensor manufacturers, end-users, certification bodies and independent evaluators to ensure the optimum use of low-cost and reliable hydrogen sensors.
Project partners analysed sensor performance in real-life applications in industrial environments and identified increased requirements for sensors and for regulations, codes and standards. H2SENSE also facilitated the safe use and implementation of hydrogen as an alternative fuel by ensuring the correct use of effective hydrogen detection devices.
European scientists worked together with colleagues from the National Renewable Energy Laboratory (NREL) in Colorado, USA. They pooled their knowledge of developments in hydrogen sensor technology as well as deployment and commercialisation strategies. These benefits will be continued through trans-Atlantic inter-laboratory sensor testing programmes in which EU and US laboratories perform complementary tests and exchange results.
Biosensors, as defined by Pure and Applied Chemistry, are ‘chemical sensors in which the recognition System utilizes a biochemical mechanism. The biological recognition system translates information from the biochemical domain, usually an analyte concentration, into a chemical or physical output signal with a defined sensitivity’.(1) It is also appointed that chemical or biological sensors contain two basic components connected in series: a chemical or biomolecular recognition System (receptor) and a physicochemical transducer. According to this prerequisite, this overlook is confined to sensor devices that combine a biomolecular recognition element with an optical signal transducer. Homogeneous or intracellular assays using fluorescent molecular probes or nanoparticles are not considered, although they are frequently termed as molecular sensors or nanosensors in the literature.
Fluorescence-based biosensors are generalized as those devices that derive an analytical signal from a photoluminescent (either fluorescence or phosphorescence) emission process. Chemi- or bioluminescent detection systems are only briefly discussed in this review.
Biosensors are used for a wide variety of tasks, including detection of compounds of biomedical, environmental or defense interest; on-line monitoring for process control; quality control of foodstuffs; selective detection of compounds undergoing a chemical separation; and screening of drug compounds. Advantages of such devices include high selectivity, rapid response times, reusability, amenability to remote analysis, and immunity to electrical interferences. The selective nature of complexation between biomolecule and analyte and the small size of sensor devices can be combined with advanced detection techiques such as total internal reflection (TIR) spectroscopy. This results in an ability to measure analytes in complex matrices with unsurpassed sensitivity. Such samples may include highly scattering components such as milk or whole blood,(11) or relatively inaccessible locations such as groundwater wells, or even intracellular environments. The key limitation of such devices mainly centers on the poor stability of biological compounds, which can lead to a substantial drift in instrumental response over time. The so-called Cambridge Definition appoints another characteristic property of sensors. Therein, they are defined as ‘miniaturized devices which can deliver real-time and on-line information on the presence of specific compounds or ions in even complex samples’. Accordingly, a sensor is expected to respond reversibly and continuously. With the exception of some enzymatic sensors, these conditions are not fulfilled in case of most biosensors. Particularly, in devices where immunological reagents or DNA are used as recognition elements, they show a lack of reversibility and operate only as a ‘one-shot’ screen, without the potential for continuous, quantitative analysis. Nevertheless, the designations immunosensors or DNA sensors became accepted for such analytical or diagnostic tools.
There is a high demand of monitoring in the era of QbD in industrial scale require new approaches to gain data rapidly and of sufficient quality in real time. Raman spectroscopy technology has great potential but not yet shown it fully in process on-line monitoring due to limitations such as i) uncomplete separation between cells and growth media alone, ii) general weak Raman signals of analytes in complex solutions and iii) strong background signals such as the auto-fluorescence, cosmic rays and surrounding lights overlapping the weak Raman signals. Here we demonstrate a Proof-of-Concept on an the example lactic acid bacteria process using a Streptococcus thermophiles fermentation. Results from three different Raman approaches are presented: 1) Time-Gated Raman Spectroscopy (TG-Raman), 2) Surface Enhanced Raman Spectroscopy (SERS) and 3) Raman process spectroscopy with NIR excitation combined with multivariate data analysis (MVDA) using Principal Component Analysis (PCA) and Partial Least Squares Regression (PLSR).
Ultrasonic methods are well established in various aspects of concrete testing. They are used for imaging the interior geometry of constructions, estimation of concrete strength or monitoring lab investigations. However, so far the detection of distributed damages, especially in an early stage, has been almost impossible. The arrival of new technologies as deep penetration ultrasonic echo devices, new imaging techniques, embedded transducers for permanent monitoring and sensitive data processing techniques adopted from seismology have opened new fields of work. Recent research has been focused to detect changes in concrete elements induced by stress, temperature, moisture or chemical attacks.
A strongly fluorescent organic semiconducting polymer doped with a highly
temperature dependent fluorescent europium(III) complex is converted into a
nanosized material that is capable of optically sensing temperature (T) in the
range from 0 to 50 °C via two-photon excitation at 720 nm. The nanosensors
are prepared from a blue-fluorescent polyfluorene that acts as both a lightharvesting
antenna (to capture two-photon energy) and an energy donor in a
fluorescence resonance energy transfer (FRET) system. The photonic energy
absorbed by the polymer is transferred to the T-sensitive red-luminescent
europium complex contained in the nanoparticles. The close spatial proximity
of the donor and the acceptor warrants efficient FRET. A poly(ethylene glycol)-
co-poly(propylene oxide) block copolymer is also added to render the particles
biocompatible. It is shown that T can be calculated from a) the intensity of
the luminescence of the europium complex, b) the ratio of the intensities of
the red and blue luminescence, or c) the T-dependent luminescence lifetime
of the Eu(III) complex.
The presentation will give an overview on non-destructive testing techniques being developed at the Federal Institute for Materials Research and Testing, Germany (BAM). This includes ultrasonic methods, ground penetration radar, Laser-Induced Breakdown Spectroscopy (LIBS), infrared thermography, pile testing, sensor technology and building scanner. A focus of the talk will be ultrasonic methods, which are well established in various aspects of concrete testing. They are used for imaging the interior geometry of constructions, estimation of concrete strength or monitoring lab investigations. However, so far the detection of distributed damages, especially in an early stage, has been almost impossible. The arrival of new technologies as embedded transducers and sensitive data processing techniques adopted from seismology has opened new field of work. Recent research has been focused to detect changes in concrete elements induced by stress, temperature, moisture or chemical attacks by permanent monitoring. Techniques as Coda Wave Interferometry can resolve changes in ultrasonic velocity in the order of 1*10-5. In addition, many researchers believe that the investigation of nonlinear effects can be used to characterize damages. The presentation will give a wrap up of ultrasonic techniques currently used in practice. This will include echo based methods as multi-channel/multi-offset imaging of structural elements using commercial and prototype devices. Imaging methods as SAFT and RTM will be shortly discussed. The focus will be on the emerging techniques used for monitoring. New types of sensors will be presented as well as the devices used in laboratory and field applications. Insight will be given on the various influence factors on ultrasonic signals and various ways of feature extraction and data processing. The results of lab experiments will be shown to demonstrate the detection of various kind of damages from mechanical load, ASR, corrosion to fatigue. The experiences with our first installations in real constructions (bridges, tunnel) will also be presented.
The presentation will give an overview on non-destructive testing techniques being developed at the Federal Institute for Materials Research and Testing, Germany (BAM). This includes ultrasonic methods, ground penetration radar, Laser-Induced Breakdown Spectroscopy (LIBS), infrared thermography, pile testing, sensor technology and building scanner. A focus of the talk will be ultrasonic methods, which are well established in various aspects of concrete testing. They are used for imaging the interior geometry of constructions, estimation of concrete strength or monitoring lab investigations. However, so far the detection of distributed damages, especially in an early stage, has been almost impossible. The arrival of new technologies as embedded transducers and sensitive data processing techniques adopted from seismology has opened new field of work. Recent research has been focused to detect changes in concrete elements induced by stress, temperature, moisture or chemical attacks by permanent monitoring. Techniques as Coda Wave Interferometry can resolve changes in ultrasonic velocity in the order of 1*10-5. In addition, many researchers believe that the investigation of nonlinear effects can be used to characterize damages. The presentation will give a wrap up of ultrasonic techniques currently used in practice. This will include echo based methods as multi-channel/multi-offset imaging of structural elements using commercial and prototype devices. Imaging methods as SAFT and RTM will be shortly discussed. The focus will be on the emerging techniques used for monitoring. New types of sensors will be presented as well as the devices used in laboratory and field applications. Insight will be given on the various influence factors on ultrasonic signals and various ways of feature extraction and data processing. The results of lab experiments will be shown to demonstrate the detection of various kind of damages from mechanical load, ASR, corrosion to fatigue. The experiences with our first installations in real constructions (bridges, tunnel) will also be presented.
Ultrasonic methods are well established in various aspects of concrete testing. They are used for imaging the interior geometry of constructions, estimation of concrete strength or monitoring lab investigations. However, so far the detection of distributed damages, especially in an early stage, has been almost impossible. The arrival of new technologies as embedded transducers and sensitive data processing techniques adopted from seismology has opened new field of work. Recent research has been focused to detect changes in concrete elements induced by stress, temperature, moisture or chemical attacks by permanent monitoring. Techniques as Coda Wave Interferometry can resolve changes in ultrasonic velocity in the order of 1*10-5. In addition, many researchers believe that the investigation of nonlinear effects can be used to characterize damages. The presentation will give a wrap up of ultrasonic techniques currently used in practice. This will include echo based methods as multi-channel/multi-offset imaging of structural elements using commercial and prototype devices. Imaging methods as SAFT and RTM will be shortly discussed. The focus will be on the emerging techniques used for monitoring. New types of sensors will be presented as well as the devices used in laboratory and field applications. Insight will be given on the various influence factors on ultrasonic signals and various ways of feature extraction and data processing. The results of lab experiments will be shown to demonstrate the detection of various kind of damages from mechanical load, ASR, corrosion to fatigue. The experiences with or first installations in real constructions (bridges, tunnel) will also be presented.
Ultrasonic methods are well established in various aspects of concrete testing. They are used for imaging the interior geometry of constructions, estimation of concrete strength or monitoring lab investigations. However, so far the detection of distributed damages, especially in an early stage, has been almost impossible. The arrival of new technologies as embedded transducers and sensitive data processing techniques adopted from seismology has opened new field of work. Recent research has been focused to detect changes in concrete elements induced by stress, temperature, moisture or chemical attacks by permanent monitoring. Techniques as Coda Wave Interferometry can resolve changes in ultrasonic velocity in the order of 1*10-5. In addition, many researchers believe that the investigation of nonlinear effects can be used to characterize damages.
The workshop will give a wrap up of ultrasonic techniques currently used in practice. This will include echo based methods as multi-channel/multi-offset imaging of structural elements using commercial and prototype devices. Imaging methods as SAFT and RTM will be shortly discussed.
The focus will be on the emerging techniques used for monitoring. New types of sensors will be presented as well as the devices used in laboratory and field applications. Insight will be given on the various influence factors on ultrasonic signals and various ways of feature extraction and data processing. The results of lab experiments will be shown to demonstrate the detection of various kind of damages from mechanical load, ASR, corrosion to fatigue. The experiences with or first installations in real constructions (bridges, tunnel) will also be presented.
We present an in situ investigation of the mechanochemical formation of cocrystals using synchrotron XRD and Raman spectroscopy. This combination allows to study milling processes on the level of the molecular and crystalline structure thus obtaining reliable data for mechanistic studies. Thereby, mechanochemical syntheses can be optimized to isolate new crystal structures.
29Si{27Al} TRAPDOR MAS NMR was applied to two faujasite-type zeolites with Si/Al ratios of 1.3 (Na-X) and 2.7 (Na-Y). The aim of this test study is to show that different Q4(mAl) sites (m=4,3,2,1) can be distinguished by differently strong TRAPDOR effects (ΔS/S0). Indeed, it was found that the TRAPDOR effect depends on the number m of AlO4 units connected to the Q4 silicon tetrahedrons. For Na-X, the measured ΔS/S0 values are 1:0.81:0.56 for Q4(4Al), Q4(3Al) and Q4(2Al), respectively (normalized to Q4(4Al)). The corresponding ΔS/S0 values are the same for Na-Y within the error bars, although the silicon sites are different: Q4(3Al), Q4(2Al) and Q4(1Al) and now normalized to Q4(3Al) as no Q4(4Al) is present. Nevertheless, the proposed method opens up the possibility to distinguish overlapping 29Si NMR signals of the Qn(mAl) sites in amorphous materials as the main goal of these investigations.
For versatile applications, including vacuum instrumentation, a liquid cell was developed. Using ultra-thin windows, this cell enables X-ray Absorption spectrometry in the soft X-ray range which is in particular interesting for the analysis of organic molecules in liquids or at the solid-liquid interface.
NEXAFS of a protein at N K-edge and of chlorophyll a at Mg K-edge is demonstrated.
In this work, fullerene has been functionalized with cyanuric Chloride at room temperature by a nitrene mediated [2 + 1] cycloaddition reaction. The adduct after functionalization is inherently in the form of azafulleroid and shows broad UV absorption in the wavelength range of 200–800 nm, as well as photothermal conversion and fluorescence with a high quantum yield.
2PM FlySCAN: Innovative approach for wide field high resolution imaging of skin tissue volumes
(2016)
Two Photon Microscopy (2PM) is an innovative Technology for high resolution imaging of human skin in vivo and ex vivo. Up to now the method is limited by its interdependence between the field of view and the attainable resolution. The new FlySCAN Technology overcomes these boundaries and enable images sizes of many millimeters by resolutions in the submicrometer range revealing very specific information on clinically and biologically relevant tissue and cell structures. The advantages of the new approach are demonstrated by excellent in vivo and ex vivo tissue images.
Copper(II)phenanthroline complexes intercalate into DNA and induce DNA cleavage. Here, we investigate the nuclease activity of copper(II)phenanthroline complexes on Silicon nitride films. 1,10-phenanthroline-5-carboxylic acid is immobilized at Si-NHx bonds via amide coupling followed by the formation of copper(II)phenanthroline complexes. XPS and NEXAFS were carried out at the HE-SGM beamline.
Multi-resistant bacteria embedded in infectious biofilms are one of the largest future threats in human healthcare. The mechanism of drug uptake and the origin of resistancy is quantitatively not well characterized and understood. Modern X-ray and synchrotron excited spectroscopic methods like XRF and NAP-XPS under ambient pressure conditions and liquid media will add new insights into this field.
Graphene prepared from Graphene oxide (GO) is used as a platform for functional 2D nanomaterials with diverse applications ranging from bios ensors to antimicrobial surfaces. C and N K-edge NEXAFS and XPS spectroscopies at BESSY’s HE-SGM beamline have been used to prove and control covalent functionalization of graphenic materials at ambient conditions for the synthesis of functional 2D-surfaces.
A novel photoswitchable rotaxane was synthesised and its switching behaviour in solution was analysed with NMR and UV-Vis. A monolayer of rotaxanes was deposited on glass surfaces and the on-surface photoswitching was investigated. Angle-resolved NEXAFS spectra revealed a preferential orientation that reversibly changes upon switching.
An automatic sample changer chamber for total reflection X-ray fluorescence (TXRF) and X-ray absorption near-edge structure (XANES) analysis in TXRF geometry was successfully set up at the BAMline at BESSY II. TXRF and TXRF-XANES are valuable tools for elemental determination and speciation, especially where sample amounts are limited (<1 mg) and concentrations are low (ng ml⁻¹ to μg ml⁻¹). TXRF requires a well defined geometry regarding the reflecting surface of a sample carrier and the synchrotron beam. The newly installed chamber allows for reliable sample positioning, remote sample changing and evacuation of the fluorescence beam path. The chamber was successfully used showing accurate determination of elemental amounts in the certified reference material NISTwater 1640. Low limits of detection of less than 100 fg absolute (10 pg ml⁻¹) for Ni were found. TXRF-XANES on different Re species was applied. An unknown species of Re was found to be Re in the +7 oxidation state.
A reversed phase high performance liquid chromatography coupled to an inductively coupled plasma mass spectrometer (HPLC-ICP-MS) approach in combination with isotope dilution analysis (IDA) for the separation and parallel quantification of nanostructured and ionic silver (Ag) is presented. The main focus of this work was the determination of the ionic Ag concentration. For a sufficient stabilization of the ions without dissolving the nanoparticles (NPs), the eluent had to be initially optimized. The determined Ag ion concentration was in a good agreement with results obtained using ultrafiltration. Further, the mechanism of the NP separation in the HPLC column was investigated. Typical size exclusion effects were found by comparing results from columns with different pore sizes. Since the recovery rates decreased with increasing Ag NP size and large Ag NPs did not elute from the column, additional interactions of the particles with the stationary phase were assumed. Our results reveal that the presented method is not only applicable to Ag NPs, but also to gold and polystyrene NPs. Finally, IDA-HPLC-ICP-MS experiments in single particle mode were performed to determine the particle cut-off size. The comparison with conventional spICP-MS experiments resulted in a similar diameter and particle size distribution.
Objectives:
Dental peri-implantitis is characterized by a multifactorial etiology. The role of metal elements as an etiological factor for peri-implantitis is still unclear. The aim of this study was to investigate the incidence of metal elements in bone and mucosal tissues around dental Grade 4 CP titanium implants with signs of peri-implantitis in human patients.
Methods:
In this prospective pilot study, all patients were enrolled consecutively in two study centers. Bone and soft tissue samples of patients with peri-implantitis with indication for explantation were analyzed for the incidence of different elements (Ca, P, Ti, Fe) by means of
synchrotron radiation X-ray fluorescence spectroscopy (SRXRF) and polarized light microscopy (PLM). The existence of macrophages and lymphocytes in the histologic specimens was analyzed.
Results:
Biopsies of 12 patients (seven bone samples, five mucosal samples) were included and analyzed. In nine of the 12 samples (75%), the SRXRF examination revealed the existence of titanium (Ti) and an associated occurrence with Iron (Fe). Metal particles were detected in peri-
implant soft tissue using PLM. In samples with increased titanium concentration, lymphocytes were detected, whereas M1 macrophages were predominantly seen in samples with metal particles.
Conclusion:
Titanium and Iron elements were found in soft and hard tissue biopsies retrieved from peri-implantitis sites. Further histologic and immunohistochemical studies need to clarify which specific immune reaction metal elements/particles induce in dental peri-implant tissue.
The project addresses chemical and topographical metrology at surfaces. The new methodologies of measurements at surfaces will be developed as good practice guides and new work item proposals for industrial ISO standards. The objectives of the Joint research project (JRP) are to provide measurement standards and methods with traceability wherever it is practicable to do so for quantitative surface chemical analysis for industrial applications.
A new concept for the self-diagnosis of embedded fiber Bragg grating (FBG) strain sensors was developed, simulated and experimentally tested. This concept is based on a magnetostrictive metallic layer directly coated on the fibre cladding over the grating segment of the FBG sensor, so that an on-demand external magnetic field in a millitesla scale can produce a controllable artificial strain as an indication signal for the remote optical interrogator. The relationship between the pre-defined magnetic field and its induced Bragg wavelength shift characterizes this validation concept. Any deviation of the local bonding state of the interfaces from the initial or/and any change of shear strain transferring mechanism from composite matrix to the optical fibre core will result in alterations in this sensitive relationship, and thus triggers an immediate alert for a further inspection. The finite element method is used to simulate the strain of this configuration as result of different values of the magnetic field in order to optimize the geometrical sensor parameters. The simulations are verified by experiments results. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
The European Water Framework Directive (WFD) 2000/60/EC specifies a list of 33 priority water pollutants. For these substances, Environmental Quality Standards (EQS), equivalent to the maximum allowable concentrations, had been defined at very low levels.
EQS values refer to the whole water body, i.e. include contaminants which are associated to suspended solids or colloids present in the natural water. For several priority pollutants primary analytical methods capable of measuring the target analytes at EQS level in natural water are still missing. The project has developed and validated such methods for three selected compounds, namely Tributyltin (TBT), Polybrominated Diphenylether (PBDE) and Polycyclic Aromatic Hydrocarbons (PAH).
Trans-Zearalenone(ZEN)is a non-steroidal estrogenic mycotoxin which frequently contaminates cereal grains worldwide. Ingestion of food and feed containing ZEN causes numerous mycotoxicoses in animals and possibly humans with pronounced estrogenic effects. Due to the trans-configurated double bond, ZEN isomerizes to the cis-configuration upon the influence of light. This work investigates the instrumental analysis, metabolism and toxicity of ZEN and cis- ZEN. The first part focused on the determination of ZEN in edible oils. Due to a maximum level of 400 µg/kg ZEN in the European Union (EU), reliable analytical methods are needed. A comprehensive method comparison proved dynamic covalent hydrazine chemistry (DCHC) to be the most suitable approach. Thus, an automated solid phase extraction (SPE) coupled online to high performance liquid chromatography (HPLC) was developed with the novelty of a covalent SPE step comprising the DCHC principle. The automated online system allows an accurate, selective and reliable quantification of ZEN in edible oils in compliance with EU performance criteria while significantly reducing workload and thereby personnel costs. In contrast to ZEN, reference standards and analytical methods are missing for cis- ZEN which causes a lack of data on the occurrence, fate and risks of cis-ZEN. Therefore, a native and an isotopically labeled cis-ZEN standard were synthesized and implemented in an existing stable isotope dilution analysis HPLC tandem mass spectrometry (HPLC-MS/MS) method. Using this method, a large extent of cis-ZEN formation was observed for ZEN contaminated maize germ oils when exposed to daylight which confirms that cis-ZEN can be a relevant food contaminant and should be considered in the analysis of food and feed. Furthermore, this work investigated the in vitro phase I metabolism of ZEN and cis-ZEN in rat and human liver microsomes by using HPLC-MS and -MS/MS analyses. The metabolic pathways of cis-ZEN were found to be essentially similar to ZEN including reduction and oxidation reactions generating α- and β-cis- zearalenol as well as 13- and 15-OH-cis-ZEN. A previously unidentified oxidative metabolic pathway for both isomers of ZEN results in the formation of cis-ZEN-11,12-oxide and ZEN-11,12-oxide in human liver microsomes. The estrogenicity of cis-ZEN and its reductive metabolites was assessed using the E-Screen assay. cis-ZEN proved to be slightly more estrogenic than ZEN. Biotransformation of cis-ZEN to β-cis-ZEL corresponds to a detoxification, whereas metabolism to α-cis-ZEL resembles a metabolic activation as its estrogenicity considerably exceeds that of cis-ZEN. The catecholic metabolites can be expected to show a decreased estrogenicity as demonstrated for 15-OH- ZEN. Independent of the estrogenic effects, the catecholic and epoxidic metabolites identified in this work can be expected to act genotoxic and carcinogenic. The epoxides in particular could fundamentally change the widely accepted view of ZEN causing adverse effects exclusively through endocrine disrupting actions.
The main task of BAM in the I4S project is the development of online analytics for reliable monitoring of major and minor nutrients like K, P, Ca in soil using mobile-XRF (X-ray fluorescence spectroscopy) and mobile-LIBS (laser-induced breakdown spectroscopy). Each method provides fast and simultaneous multi-element analyses which are neccessary for mapping agricultural cropland. The first objective was to design a combined measurement setup for XRF and LIBS. The centerpiece is the rotatable sample plate which enables the measurement of moving samples. Current steps are the optimisation of the parameters for the analysis of soils.
Production of soil reference materials (for project partners) is integrated into the project „X-ray fluorescence, laser-induced breakdown spectroscopy (and Raman spectroscopy) as tools for a site-specific management of soil fertility“. BAM provides good analytics which is necessary for measuring the right values. Why is it important to have reference values? They enable the connection of own measuring results to the SI (international system of units) and the comparison with results from other laboratories. The soil reference materials are also needed for the calibration of the matrix dependent methods laser-induced breakdown spectroscopy (LIBS) and X-ray fluorescence analysis (XRF). For the production of soil reference materials different steps are required, for example drying, sieving and homogenisation.
The main task of BAM in the I4S project is the development of online analytics for reliable monitoring of major and minor nutrients like K, P, Ca in soil using mobile-XRF (X-ray fluorescence spectroscopy) and mobile-LIBS (laser-induced breakdown spectroscopy). Each method provides fast and simultaneous multi-element analyses which are neccessary for mapping agricultural cropland. The first objective was to design a combined measurement setup for XRF and LIBS. The centerpiece is the rotatable sample plate which enables the measurement of moving samples. Current steps are the optimisation of the parameters for the analysis of soils.