Analytische Chemie
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The paintings and manuscripts discovered in the sealed ‘library cave’ in Dunhuang, Western China, contain the earliest surviving examples of Tibetan artistic and scribal practice (9the10th centuries AD). Despite their importance, their material characteristics have not previously been studied. The present paper discusses the results of the analysis of paper and pigments in a selection of items across a variety of forms and functions: (i) Buddhist manuscripts, (ii) official letters, (iii) hung paintings, (iv) ritual items, (v) banners, and (vi) stencils and preliminary sketches. The material analysis of these items is presented in historical context, to address three research questions. First, whether there is a correspondence between the materials used in the creation of these objects and their geographical origin. Second, in terms of the choices made in the available materials and techniques, whether there is a detectable correlation between materials chosen and the intended function of the objects. Third, whether the characteristics of the objects analysed here be considered to be part of a broader Central Asian artistic and scribal culture. The authors conclude that a local culture of paper and pigment production can be detected in these results, though further research is needed especially on the geographical origin of raw materials for pigments. The results show that artists and scribes made technological choices in paper and pigments depending on the function of the objects they were creating. Finally, understanding of the broader Central Asian context of these results will depend on future analysis of material from other archaeological sites, and comparison with the results of this study.
Sixteen Ayyubid-Mamluk glazed pottery sherds were analyzed in order to identify and characterize the elemental composition to determine their provenance. The tested sherds were collected from the historical site of Karak Castle, southern Jordan.
Chemical analysis for the sixteen samples has been carried out using Synchrotron Radiation X-ray Fluorescence Spectrometry (SR-XRF) Technique. Furthermore, the semiquantitative analysis of the elements Fe – Cu – Zn – Br – Rb – Sr – Y – Zr – Nb – Mo – Pd – Ag – Cd and Pb has been performed for the samples based on Principal Component Analysis (PCA) and hierarchical Cluster Analysis with Bray-Curtis in order to define grouping of different glazed pottery by obtaining information on their similarity and clustering. The results of chemical analysis provided persuasive evidence that the Karak Castle pottery sherds have at least three different sources of provenance.
The qualitative and quantitative investigations of historical iron-gall inks by use of μ-XRF spectrometry is a common method for analyzing the diff erences in their composition. When a fingerprint is established, it is possible to characterize the distinguishable inks used in the production of medieval manuscripts, and, in turn assist in the reconstruction of the manuscript’s history.The characterization of the primary inks in palimpsests, i.e. manuscripts written on re-used parchment, presents a serious problem as the effect of the partial removal on the inks fi ngerprint is yet known.
In this paper we explore our preliminary results concerning the effects of two removal techniques on the fingerprint of iron-gall inks on parchment.
CCQM key comparison K-129 for the quantitative analysis of Cu(In,Ga)Se2 (CIGS) films has been performed by the Surface Analysis Working Group (SAWG) of the Consultative Committee for Amount of Substance (CCQM). The objective of this key comparison is to compare the equivalency of the National Metrology Institutes (NMIs) and Designated Institutes (DIs) for the measurement of mole fractions of Cu, In, Ga and Se in a thin CIGS film. The measurand of this key comparison is the average mole fractions of Cu, In, Ga and Se of a test CIGS alloy film in the unit of mole fraction (mol/mol). Mole fraction with the metrological unit of mol/mol can be practically converted to atomic fraction with the unit of at%.
In this key comparison, a CIGS film with certified mole fractions was supplied as a reference specimen to determine the relative sensitivity factors (RSFs) of Cu, In, Ga and Se. The mole fractions of the reference specimen were certified by isotope dilution - inductively coupled plasma/mass spectrometry (ID-ICP/MS) and are traceable to the SI. A total number counting (TNC) method was recommended as a method to determine the signal intensities of the constituent elements acquired in the depth profiles by Secondary Ion Mass Spectrometry (SIMS), X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). Seven NMIs and one DI participated in this key comparison. The mole fractions of the CIGS films were measured by depth profiling based-SIMS, AES and XPS. The mole fractions were also measured by non-destructive X-Ray Fluorescence (XRF) Analysis and Electron Probe Micro Analysis (EPMA) with Energy Dispersive X-ray Spectrometry (EDX).
In this key comparison, the average degrees of equivalence uncertainties for Cu, In, Ga and Se are 0.0093 mol/mol, 0.0123 mol/mol, 0.0047 mol/mol and 0.0228 mol/mol, respectively. These values are much smaller than that of Fe in a Fe-Ni alloy film in CCQM K-67 (0.0330 mol/mol). This means that the quantification of multi-element alloy films is possible by depth profiling analysis using the TNC method.
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.
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.
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.
Gold ist eines der sieben schon im Altertum bekannten Metalle und wurde wg. seines Glanzes und seiner Seltenheit von alters her als Tauschmittel und zur Herstellung von Schmuck benutzt. Außerdem ist es einfach bearbeitbar und weitestgehend gegen chemische Einflüsse resistent.
Die Untersuchungen von Gold mit synchrotronstrahlungsangeregter Röntgenfluoreszenzanalyse sind zerstörungsfrei und geben Auskunft über die in der untersuchten Probe vorhandenen chemischen Elemente.
Bei den hier vorgestellten Untersuchungen an der BAMline stehen Fragestellungen wie Herkunft, Herstellungsverfahren und Zusammengehörigkeit von Goldfunden im Vordergrund. Die verschiedenen Fragestellungen werden an einer Reihe von Beispielen erläutert die vom Wikingerschatz aus Hiddensee über die Himmelsscheibe von Nebra bis hin zu Funden aus Ägypten langen. Zusätzlich werden die modernen Messmethoden vorgestellt, die am Synchrotron heutzutage zur Verfügung stehen.
Gold ist eines der sieben schon im Altertum bekannten Metalle und wurde wg. seines Glanzes und seiner Seltenheit von alters her als Tauschmittel und zur Herstellung von Schmuck benutzt. Außerdem ist es einfach bearbeitbar und weitestgehend gegen chemische Einflüsse resistent.
Die Untersuchungen von Gold mit synchrotronstrahlungsangeregter Röntgenfluoreszenzanalyse sind zerstörungsfrei und geben Auskunft über die in der untersuchten Probe vorhandenen chemischen Elemente.
Bei den hier vorgestellten Untersuchungen an der BAMline stehen Fragestellungen wie Herkunft, Herstellungsverfahren und Zusammengehörigkeit von Goldfunden im Vordergrund. Die verschiedenen Fragestellungen werden an einer Reihe von Beispielen erläutert die vom Wikingerschatz aus Hiddensee über die Himmelsscheibe von Nebra bis hin zu Funden aus Ägypten langen. Zusätzlich werden die modernen Messmethoden vorgestellt, die am Synchrotron heutzutage zur Verfügung stehen.
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.