Non-invasive identification of organic materials in wall paintings by fiber optic reflectance infrared spectroscopy: A statistical multivariate approach

INSTM Operative Unit of Perugia c/o Dipartimento di Chimica, Università di Perugia, 06123 Perugia, Italy.
Analytical and Bioanalytical Chemistry (Impact Factor: 3.44). 09/2009; 395(7):2097-106. DOI: 10.1007/s00216-009-3108-y
Source: PubMed


The aim of this study is to develop a method for the non-invasive and in situ identification of organic binders in wall paintings by fiber optic mid-FTIR reflectance spectroscopy. The non-invasive point analysis methodology was set-up working on a wide set of wall painting replicas of known composition and using statistical multivariate methods, in particular principal component analysis (PCA), for the interpretation, understanding, and management of data acquired with reflectance mid-FTIR spectroscopy. Results show that PCA can be helpful in managing and preliminary sorting of the large amount of spectra typically collected during non-invasive measurement campaigns and highlight further avenues for research. The developed PCA model was finally applied to the case of a Renaissance wall painting by Perugino assessing it predictability as compared to the interpretation of the single spectrum.

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    • "In the field of cultural heritage, non-invasive in-situ NIR spectroscopy investigations have been profitably applied for the identification of paint materials [11] [12] [13] [14] [15] and for the evaluation of the long-term stability of historical papers [16]. Recently, Dooley et al. proposed the use of an advanced NIR reflectance imaging system for the identification of organic substances in paintings, exploiting the vibrational overtones and combination bands of fundamental absorptions, which are less affected by potential pigment interferences [17]. "
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    ABSTRACT: The present research was aimed at exploiting and evaluating the potentialities of FT-NIR microscopy, as a complementary approach to analysis in the MIR region, for the chemical characterisation of paint cross sections. Even if FT-NIR technique is still underutilised in the field of cultural heritage investigations, the integrated use of information recorded in the NIR and in the MIR regions proved to be extremely useful in the molecular investigation of organic and inorganic substances. In fact, combination and overtone bands present in the NIR region, even if weaker and less selective than those in the MIR region, are not distorted by reflection phenomena. Furthermore, NIR spectra can be efficiently used as a spectral fingerprint for the stratigraphic characterisation of paint cross sections. The proposed analytical protocol was applied on two historical samples, presenting different stratigraphic structures. Suitable chemometric methods were applied for the elaboration of multivariate chemical maps recorded in the range 700–7500 cm− 1. In particular, a comprehensive and efficient procedure based on an interactive brushing approach, which combines the structural information of the score scatter plots with the spatial information of the PC score maps, was used. Interestingly, NIR data allowed a thorough characterisation of paint structures, providing information for the identification of components and suggesting the differentiation among different types of proteins. Moreover, NIR spectra permitted to achieve an efficient distinction of different classes of natural resins, demonstrating that, even working at a microscopic level, the NIR region may support the identification of different terpenoid materials. Multivariate analysis performed on MIR data did not provide satisfactory results, probably due to the distortion of the spectra and overlapping of bands. Nevertheless, MIR outcomes were investigated to support the interpretation of NIR spectra and in attempt to define an integrated protocol for the characterisation of complex paint mixtures.
    Microchemical Journal 01/2014; 112:87–96. DOI:10.1016/j.microc.2013.09.021 · 2.75 Impact Factor
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    • "In fact, organic matters (such as egg yolk rich in proteins and fatty acids) are the main ingredient, together with inorganic pigments, of the medieval tempera (Huang et al. 2003; Hosamani and Pattanashettar 2003) and they could have supported the microbial growth. In addition, very often, during restoration interventions, several organic materials, such as natural and synthetic adhesives and consolidants, are used (Casadio et al. 2004; Rosi et al. 2009). "
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    ABSTRACT: The aim of this study was to find a correlation among the environmental isolated microflora and the fresco colonizators through the investigation of their biodegradative abilities and DNA characteristics. A molecular technique named RAMP (Random Amplified Microsatellite Polymorphisms) was utilized in order to analyze the DNA diversity of bacterial and fungal species isolated from fresco as well as from air samples. The RAMP-PCR results were combined with the screening of some biodegradative properties obtained through the use of specific agar plate assays detecting the proteolytic, solubilization and biomineralization abilities of the isolated microflora. This comparative analysis showed that only in few cases a direct link among the fresco and airborne isolates of specific microbial group existed. The investigation clearly evidenced that colonization of surface of Ladislav's fresco occurred in different time and by different strains than those observed at the moment of sampling campaign. Furthermore, the microflora investigation permitted the identification of taxonomically interesting bacteria with particular biodegradative properties, which had been less studied until now.
    World Journal of Microbiology and Biotechnology (Formerly MIRCEN Journal of Applied Microbiology and Biotechnology) 05/2012; 28(5):2015-27. DOI:10.1007/s11274-012-1004-7 · 1.78 Impact Factor
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    • "In the last years, great advances have been achieved in the development of non-invasive analytical tools. New instrumentation has been developped to provide valuable information that ranges from the identification of original materials and the characterization of alteration phases [1] [2] [3] [4] [5] [6] [7] to the imaging of materials distribution on the surface and behind the surface [8] [9] [10] [11]. The miniaturization of electronic components and advances on fibre-optic technology had lead to the assembly of portable instrumentations with capabilities that are comparable to standard bench equipments. "
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    ABSTRACT: The main advantage of a multi-technique non-invasive artwork investigations relies on the use of different spectroscopic techniques that give rise to complementary information. Despite the artworks complexity, this approach allows great insight into the artwork composition and alteration phases. However, difficulties arise from the great amount of heterogeneous interconnected data that has to be stored for a prompt analysis and preserved. A suitable tool to handle and analyse all the information on the fly is therefore crucial to optimize work, specially in in situ investigations. In this paper we present MOVIDA, a new tool for the data management and analysis of non-invasive investigations in the Cultural Heritage field that not only allows the digital preservation of all the information and knowledge, but can also be used as an analytical tool while the investigation is being developed. The software can be installed on any computer to record, elaborate and analyse the data on-the-spot. All the data generated can be managed within the same application and the information can be easily consulted, compared and related to the corresponding areas of the artwork. The software is self-comprehensive and user-friendly and can be used by all the professionals involved in the investigation and preservation of Cultural Heritage whatever their background and computer skills are.
    Journal of Cultural Heritage 01/2012; DOI:10.1016/j.culher.2012.02.015 · 1.57 Impact Factor
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