S. Pessanha

Noninvasive and nondestructive NMR, Raman and XRF analysis of a Blaeu coloured map from the seventeenth century

A complete multianalytical study of a hand-coloured map from the seventeenth century is presented. The pigments atacamite, massicot, minium, gypsum, carbon black and vermilion were determined by means of XRF and Raman spectroscopy. The state of conservation of the cellulosic support was monitored by means of unilateral NMR. The analysis was nondestructive and noninvasive, and thus several spectra were collected from the same areas, yielding more reliable results without damaging the artwork. The role of copper pigments in the oxidation processes observed in the cellulosic support is discussed, as well as the possible provenance of atacamite as a raw material instead of as a degradation product of malachite.

Analysis of a coloured Dutch map from the eighteenth century: the need for a multi-analytical spectroscopic approach using portable instrumentation.

A Dutch map from the eighteenth century was multi-analytically analysed making use of energy dispersive X-ray fluorescence (EDXRF), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), Raman and scanning electron microscopy coupled to energy dispersive spectrometry (SEM-EDS). The cellulosic support was characterised and its state of conservation was evaluated. Besides, paramagnetic impurities were detected together with copper metallic chips. The colours present in some areas of the map were also analysed. Vermilion, carbon black and organic pigments were found. Surprisingly, in the green areas, the rare presence of the mineral moolooite (copper oxalate) was detected. A possible biological attack is discussed in order to explain the presence of such compound. Almost all of the techniques used in the analysis were portable, non-destructive and non-invasive, which is very desirable when analysing objects belonging to Cultural Heritage. The need for a multi-analytical approach using portable instrumentation is also discussed.

Characterisation of foxing stains in eighteenth to nineteenth century drawings using non-destructive techniques

The reddish-brown, brown or yellowish stains of circular or irregular shape known as foxing spots have been fully described in conservation literature but still, this phenomenon does not find any scientific agreement since many hypotheses have been raised concerning their origin. In this work a contribution to foxing definition not only focussed on its appearance but also reported on its chemical information. For this purpose foxing stains present in drawings from two Portuguese artists dated from the eighteenth to nineteenth centuries were observed under ultra-violet light and optical microscope and analysed by three non-invasive spectroscopy techniques. The observations carried out on the stains provided information on their surface morphology. The use of energy-dispersive X-ray fluorescence revealed a variation on the elemental content between foxing and paper region. Although the results from X-ray diffraction analysis showed no signs of cellulose degradation in foxing stains, Fourier-transformed infrared analysis revealed the presence of oxide groups. Both the information on the chemical nature and surface morphology of the stains achieved in this study will contribute to increase foxing formation information and develop future protocols for conservation purposes.

Performance of three different Si X-ray detectors for portable XRF spectrometers in cultural heritage applications

In this work, a study of detection systems in portable X-ray fluorescence (PXRF) spectrometry was performed. An assessment of various detectors and their influence on the measurement of trace elements in different bulk materials, from light to heavy matrices, was done. Four reference materials were analyzed: Orchard Leaves (NBS-1571); Bone Meal (NIST-1486); River Sediment (NBS-1645) and Free-Cutting Brass (NBS-1105). Detection limits were calculated for the elements present in the reference materials, quantitative calculations were performed for three known samples and a comparison was made for each detector. Three case studies were also performed in order to appraise the behavior of the detection systems: A paper document from 1909, a potassium alum/calcite mixture and a Portuguese coin.

Spectroscopic characterization of a masterpiece: The Manueline foral charter of Sintra

The foral charter attributed by D. Manuel I of Portugal, in 1514, to the village of Sintra was studied using Energy Dispersive X-ray Fluorescence spectrometry, Raman and Infrared micro-spectroscopies. A complete characterization of the pictorial materials used in the production of this masterpiece allowed the identification of iron gall inks used in the written text; pigments such as malachite, azurite, lead white, cinnabar, yellow ochre, gold, silver and carbon black in the illuminations and letterings; filler and binder used in the production of coloring materials and inks. Gum and calcium carbonate were the most recurrent binder and filler identified in this study. Silvering and gilding were mostly obtained by applying ground silver and gold on parchment.

New development on materials and techniques used in the heraldic designs of illuminated Manueline foral charters by multi-analytical methods.

In the illuminated foral charters commissioned by D. Manuel I, King of Portugal (1495-1521), heraldry played a prominent role. In this work, royal emblems corresponding to the third heraldic design, applied to the Charter of Couto de Teixedo, are studied by means of EDXRF, SEM-EDS, micro-Raman, micro-FTIR and HPLC-DAD to characterize the materials and techniques used to produce this masterpiece of Portuguese Renaissance. By comparing this data with the results previously obtained in other three charters, this research allows for the first time an accurate insight into the reformed manuscripts production, especially since the illuminated charters under consideration were all investigated on the basis of similar micro-spectroscopic techniques. Inks, metal coatings, pigments, organic dyes, fillers or extenders, and binding media are discussed, and their use enlightened by the politic and legal messages the foral charters had to convey. Parchment analysis allowed us to identify the animal species, and all undertaken processes along its preparation. HPLC-DAD allowed us to differentiate the gums used. CaSO4 was observed in the parchment as a degradation product of CaCO3 used in parchment production in the presence of metal sulfates coming from the ink. Pigments used in the different colors as well as some specific phases for some colors were identified. Silvering and gilding processes, metal caratage and silver oxidation compounds were also objects of the present study.

Analysis of lead content in automotive shredder residue (ASR)

Automotive shredder residue (ASR) is a very heterogeneous waste, which could have a very high metal content on finest fractions phi<6 mm produced by the shredding of end of live vehicles. The approval of Directive 2000/53/EC and its transposition to the European Union member states requires an analytical technique for in-situ checking of the content of some metals in ASR wastes. The objective of this study is the evaluation of total Pb content in the different fractions using a rapid measurement method to easily accomplish the current legislation. An experimental Energy Dispersive X-ray Fluorescence (EDXRF) spectrometer with tri-axial geometry was used to analyse the ASR in order to test the feasibility of this analytical technique. Likewise, a correction of the intensities by the incoherent scattering (Compton) radiation was made to compensate the matrix effects. The results show that values in the smaller fractions are bigger (11,600 mg kg(-1) in the fraction <125 microm) than in the coarser fractions (4600 mg kg(-1) in the fraction between 2 and 6 mm) and that such type of instrumentation enables a fast measurement with a limit of detection of 1.1 mg kg(-1) for 1000 s measurement).

Development of a combined portable x-ray fluorescence and Raman spectrometer for in situ analysis

In this work, we have built a portable X-ray fluorescence (XRF) spectrometer in a planar configuration coupled to a Raman head and a digital optical microscope, for in situ analysis. Several geometries for the XRF apparatus and digital microscope are possible in order to overcome spatial constraints and provide better measurement conditions. With this combined spectrometer, we are now able to perform XRF and Raman measurements in the same point without the need for sample collection, which can be crucial when dealing with cultural heritage objects, as well as forensic analysis. We show the capabilities of the spectrometer by measuring several standard reference materials, as well as other samples usually encountered in cultural heritage, geological, as well as biomedical studies.

Quantitative analysis of human remains from 18th–19th centuries using X-ray fluorescence techniques: The mysterious high content of mercury in hair

In this work, we report the unusual concentration of mercury in the hair of an individual buried in the 18th to mid-19th centuries and the comparison with the elemental composition of other remains from the same individual. Two energy dispersive X-ray fluorescence (EDXRF) setups, one with tri-axial geometry and the second one with micro-beam capabilities and a vacuum system, for light elements detection, have been used. Quantitative evaluation of the obtained spectra were made by fundamental parameters and winAXIL program by compare mode method. The levels of Hg in the hair of buried samples presented a concentration over 5% (w/w), a significantly lower presence of this element in the cranium, and no Hg in the remaining organs. Furthermore, there was no evidence of Hg in the burial soil, which has been also analyzed. From this result, we could conclude that the possibility of post-mortem contamination from the burial surroundings is very unlikely. The obtained results are indicative of the apparent use of a mercury-based compound for medical purposes, most likely lice infestation.

Quantitative evaluation of ante-mortem lead in human remains of the 18th century by triaxial geometry and bench top micro X-ray fluorescence spectrometry

The aim of this work is to demonstrate the suitability of the commercial benchtop micro X-ray fluorescence (μ-XRF) system M4 Tornado, to evaluate the differences in lead distribution in different bone and tooth structures. Ante-mortem and post-mortem Pb accumulation was also assessed and the lead amount in different tissues was compared. Micro-XRF based on polycapillary systems is a relatively new technique with capabilities to provide multielemental maps and quantitative measurements. Another advantage of the technique is being non-destructive and requiring only a small amount of sample. In this work, we measured the lead concentration in human remains, bone and tooth of an 18th century young male subject, around 30 years old, and compared the results obtained using μ-XRF with a setup with a triaxial geometry. Accuracy of the microanalytical system for pressed pellets and cross-sections of bone and tooth was also certified. The μ-XRF setup provided analytical point spectra, line profiles and elemental maps for Pb and Ca distribution in bone and tooth. The quantitative calculations were performed by the fundamental parameter and compare mode methods. The accuracy and the detection limits were checked using standard reference materials for Ca, Zn, Sr and Pb. Furthermore, unusual extremely high amounts of Pb in cortical bone, tibia and fibula were observed, reaching 120 ± 10 μg g−1, while the trabecular region reached 250 ± 20 μg g−1. Rib presented the highest levels, 560 ± 30 μg g−1. In the tooth structure, the highest amount of Pb was found in pulp and root with 130 ± 50 μg g−1. Low levels of Pb in the surrounding soil have been found.