Direct microextraction for red lakes detection in painting layers by Raman spectroscopy

Anno: 2021

Autori: Innocenti S., Ricci M., Lanterna G., Fontana R., Striova J., Becucci M.

Affiliazione autori: CNR INO Natl Res Council, Natl Inst Opt, Largo E Fermi 6, I-50125 Florence, Italy; Univ Florence, Dept Chem Ugo Schiff, Via Lastruccia 3-13, I-50019 Sesto Fiorentino, FI, Italy; Opificio Pietre Dure MiC, Lab Sci, Viale F Strozzi 1, I-50129 Florence, Italy.

Abstract: Identification of red lakes-obtained by precipitation or adsorption of dyes onto an inorganic substrate-is of fundamental importance for the study of their manufacturing technology and for their conservation, but this poses an analytical challenge. We show how the detection of red lakes in painting layers by Raman spectroscopy can be enhanced. We propose to exploit the solubility of red lakes and their subsequent recrystallization in a hydrogel as a way to isolate the lake from the painted matrix. This analytical method has been found to be an effective tool for the identification of cochineal and madder lakes present in painting layers. The obtained results are compared to available experimental data and DFT calculations, and it is possible to define the organometallic complex present in the hydrogel after the micro-extraction process. We test and demonstrate the efficiency of this methodology on naturally aged mock-up panel paintings and on a historical painting. Reflectance spectra and colorimetric measurements by Fiber Optics Reflectance Spectroscopy are employed to support the Raman data and to evaluate the colorimetric parameters following the micro-extraction.

Giornale/Rivista: EUROPEAN PHYSICAL JOURNAL PLUS

Volume: 136 (10)      Da Pagina: 1081-1  A: 1081-18

Maggiori informazioni: The work was performed within the project on Advanced Raman spectroscopy, Joint Advanced Education Project, co-financed by the Tuscany Region with the resources of the POR FSE 2014-2020-Axis A Employment, “Giovanisi” as part of the Intervention program called “CNR4C”.
Parole chiavi: micro-extraction, agar-gel, Raman spectroscopy, red lakes, Pietro Lorenzetti
DOI: 10.1140/epjp/s13360-021-02069-5

Citazioni: 5
dati da “WEB OF SCIENCE” (of Thomson Reuters) aggiornati al: 2025-04-20
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