Complementary cross-section based protocol of investigation of polychrome samples of a 16th century Moravian Sculpture by optical, vibrational and mass spectrometric techniques

On the occasion of its restoration treatments, the rare medieval polychrome sculpture entitled The Mourning of Jesus Christ (16th century, belonging to the Moravian Gallery in Brno, Czech Republic) was subject to a detailed analytical investigation in order to identify the organic and inorganic materials present in the polychrome layers and to map their distribution in the paint structure. This knowledge is extremely useful especially for art objects that suffered reconstructions and/or over paintings or other interventions and can be of help to the restorers in deciding the best conditions and materials for the treatment. In this case, the identification of all components was very important in terms of the assessment of the original painting techniques and discrimination of the presence of over painting layers, being complemented by the study of the construction process and of the history of the artwork. Until recently, the identification of proteinaceous binders contained in small samples taken from polychrome or painted works of art was very complicated and nearly impossible in the case of cross-section analyses. Therefore, the novelty of this paper is the complementary applications of several analytical techniques, such as optical microscopy (OM), nano-LC-ESI-Q-TOF and MALDI-TOF mass spectrometry, microRaman spectroscopy and scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM-EDX) directly on cross-sections. This approach is especially useful for this case as only few samples were available for binder and pigment identification and it allowed the preservation of the samples as cross-sections for further analyses. (C) 2013 Elsevier B.V. All rights reserved.