Characterization of fresh and aged natural ingredients used in historical ointments by molecular spectroscopic techniques: IR, Raman and fluorescence

Brambilla, Luca; Riedo, Chiara; Baraldi, Cecilia; Nevin, Austin; Gamberini, Maria Cristina; D’Andrea, Cosimo; Chiantore, Oscar; Goidanich, Sara; Toniolo, Lucia

doi:10.1007/s00216-011-5168-z

Cited by 32 publications

(24 citation statements)

References 33 publications

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“…This is caused by the reactions between zinc ions of the pigment and fatty acids contained in the binding medium, leading to formation of zinc carboxylates, which are easily detected by Fourier transform infrared spectroscopy (FTIR) [11,12]. Clementi et al worked on different mixtures of zinc white with oils and alkyd medium, observing the generation of a broad band at about 1600 cm −1 with infrared spectroscopy [13].…”

Section: Introductionmentioning

confidence: 99%

A Photoluminescence Study of the Changes Induced in the Zinc White Pigment by Formation of Zinc Complexes

et al. 2017

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It is known that oil paintings containing zinc white are subject to rapid degradation. This is caused by the interaction between the active groups of binder and the metal ions of the pigment, which gives rise to the formation of new zinc complexes (metal soaps). Ongoing studies on zinc white paints have been limited to the chemical mechanisms that lead to the formation of zinc complexes. On the contrary, little is known of the photo-physical changes induced in the zinc oxide crystal structure following this interaction. Time-resolved photoluminescence spectroscopy has been applied to follow modifications in the luminescent zinc white pigment when mixed with binder. Significant changes in trap state photoluminescence emissions have been detected: the enhancement of a blue emission combined with a change of the decay kinetic of the well-known green emission. Complementary data from molecular analysis of paints using Fourier transform infrared spectroscopy confirms the formation of zinc carboxylates and corroborates the mechanism for zinc complexes formation. We support the hypothesis that zinc ions migrate into binder creating novel vacancies, affecting the photoluminescence intensity and lifetime properties of zinc oxide. Here, we further demonstrate the advantages of a time-resolved photoluminescence approach for studying defects in semiconductor pigments.

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Section: Introductionmentioning

confidence: 99%

A Photoluminescence Study of the Changes Induced in the Zinc White Pigment by Formation of Zinc Complexes

et al. 2017

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“…On the other hand, C-O-C ring vibration, also described by PC4, shows the specific frequency related to TG: the characteristic singlet at 857 cm −1 [22,24]. Additionally, another minor contribution, ascribable to gums, is the combination band of OH stretching and bending.…”

Section: Pca Applied On Combined First Derivative Ft-nir Andmentioning

confidence: 95%

“…In addition, no amide I and amide III bands are present, in contrast to proteinaceous binders [22,24]. The rather broad peaks in the 1500-1200 cm −1 region are ascribed to C-H deformations, whereas the peaks at lower wavenumbers are associated with C-C and C-O symmetrical stretching modes (1200-950 cm −1 ) and C-O-C sugar ring vibrations (950-800 cm −1 ) [22,24]. The Raman spectrum of Arabic gum shows a doublet at around 850 cm −1 (882 cm −1 and 841 cm −1 ), whereas tragacanth gum has a singlet (857 cm −1 ).…”

Section: Ft-nir and Micro-raman Spectra Of Different Bindersmentioning

confidence: 98%

“…Gums dataset displays a negative score value for PC1, whereas it has a positive score value for PC2 ( Figure 5). As can be seen in Figure 6(a), the greatest contributions to PC1 related to polysaccharide-based binding media are represented by the combination band of O-H stretching and bending (∼ 5140 cm −1 ) [21], the combination band of C-H and C-C/C-O-C stretching modes (∼4010 cm −1 ) [21], and the C-O-C sugar ring vibrations (950-800 cm −1 ) [22,24]. As regards PC2, the main highlighted polysaccharide vibrations are the combination band of O-H stretching and bending and the C-O-C sugar ring vibrations (Figure 6(a)).…”

Section: Pca Applied On Combined First Derivative Ft-nir Andmentioning

confidence: 99%

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Vibrational Spectroscopies and Chemometry for Nondestructive Identification and Differentiation of Painting Binders

Carlesi

Becucci

Ricci

2017

Journal of Chemistry

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A comprehensive dataset of vibrational spectra of different natural organic binding media is presented and discussed. The binding media were applied on a glass substrate and analyzed after three months of natural ageing. The combination of Raman and FT-NIR spectroscopies allows for an improved identification of these materials as Raman technique is more informative about the skeletal vibrations, while FT-NIR spectroscopy is more sensitive to the substituents and polar groups. The experimental results are initially discussed in the framework of current spectral assignment. Then, multivariate analysis (PCA) is applied leading to differentiation among the samples. The two major principal components allow for a complete separation of the different classes of organic materials. Further differentiation within the same class is possible thanks to the secondary components. The loadings obtained from PCA are discussed on the basis of the spectral assignment leading to clear understanding of the physical basis of this differentiation process.

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“…In addition, chemical analyses revealed the presence of residues of tryptophan and phenolic compounds [28], both also being contributors to fluorescence emission. Upon excitation at 366 nm, the fluorescence from the amino acids of proteins is not excited and the observed feature can be ascribed to the degradation products of the amino acids (phenylalanine, tyrosine and tryptophan) and to compounds formed between sugars and reducing proteins in the Maillard reaction [24,[29][30][31]. When adding the pigments, changes are observed in the intensity and maximum position of the fluorescence of the gum arabic, due to the interactions between the binder and pigments.…”

Section: Spectrofluorimetrymentioning

confidence: 99%

Hyperspectral imaging, spectrofluorimetry, FORS and XRF for the non-invasive study of medieval miniatures materials

et al. 2014

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Background: Illuminated manuscripts are complex multi-layer and multi-material objects. To this difficulty, from the analytical point of view, is added the impossibility of removing samples from these paintings for the study of their materials and techniques. There are relatively few analytical methods that satisfy these constraints as the availability of non-invasive techniques adapted to painted manuscripts is limited and mainly focused on the characterization of inorganic compounds. In the context of a research project on the analytical study of the forty miniatures in the Marcadé collection (Treasury of the Saint-André Cathedral of Bordeaux, XIII to XVI century), the potential of two non-invasive methods, hyperspectral imaging (HSI) and spectrofluorimetry is explored. Results: The methodological development of these techniques as well as preliminary tests on miniatures recreated according to medieval recipes and materials, allowed the validation of the analytical parameters and the creation of a database of reference spectra (parchments, pigments, binders). Hyperspectral imaging associates reflectance spectra with each pixel of the image and treats the signal received in various wavelengths. The characteristics of the spectral signal in VIS range or NIR are used to get an identification and a localization of the components. It allows the study of the entire image and offers lots of ways to work: comparison of spectra, mapping, principal component analyses and false color images. Spectrofluorimetry is a sensitive method which gives information on fluorescent organic compounds under UV or visible light. Emission and excitation spectra of five red pigments in binding media have been collected. These methods were compared with X-ray fluorescence spectrometry for the qualitative analysis and mapping of the inorganic elements in a facsimile which had been purposely reproduced by an illumination painter who worked with original medieval recipes for the sake of developing the present study. Conclusions: The combination of all these techniques allows good identification of all the materials used on an illuminated manuscript. The pertinent selection of the wavelengths used with the HSI system and a preliminary database and study of materials under UV and white light is described in this paper.

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Characterization of fresh and aged natural ingredients used in historical ointments by molecular spectroscopic techniques: IR, Raman and fluorescence

Cited by 32 publications

References 33 publications

A Photoluminescence Study of the Changes Induced in the Zinc White Pigment by Formation of Zinc Complexes

A Photoluminescence Study of the Changes Induced in the Zinc White Pigment by Formation of Zinc Complexes

Vibrational Spectroscopies and Chemometry for Nondestructive Identification and Differentiation of Painting Binders

Hyperspectral imaging, spectrofluorimetry, FORS and XRF for the non-invasive study of medieval miniatures materials

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