Portable Raman spectroscopy

Raman Spectroscopy is a non-destructive chemical analysis technique based upon the interaction of light with the chemical bonds within a material. It provides fundamental information about the chemical structure of the molecules and allows discriminating different phases and polymorphisms, as well as characterize the molecular interactions within a substance.

The Raman technique is widely used for the analysis of any type of material (inorganic, organic, crystalline, amorphous) and is very powerful tool for the identification of pigments and dyes, as well as for the identification of restoration materials and degradation products on works of art.

The BWTEK micro-Raman spectrometer available at the CNR-IFAC Sabec laboratories was used for the present study. The spectrometer is equipped with a 785 nm laser and operating in the 3200-80 cm-1 spectral range. The head is connected to the laser and the spectrometer by means of two optical fibers and is equipped with a 5 mm NIR lens and a 40X microscope objective to focus the laser radiation on the sample, resulting in a spot with a diameter of approximately 2 μm on the investigated area. The head is internally equipped with a notch filter to allow the collinearity of the output laser and the Raman spectrum input from the measurement optics.

Portable Micro-Raman set up at Biblioteca Nazionale Vittorio Emanuele III of Naples.

References

1. Aceto, M. and Calà, E., 2017. Analytical evidences of the use of iron-gall ink as a pigment on miniature paintings. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 187, pp.1-8.
2. Aceto, M., Agostino, A., Boccaleri, E., Crivello, F. and Garlanda, A.C., 2006. Evidence for the degradation of an alloy pigment on an ancient Italian manuscript. Journal of Raman Spectroscopy: An International Journal for Original Work in all Aspects of Raman Spectroscopy, Including Higher Order Processes, and also Brillouin and Rayleigh Scattering, 37(10), pp.1160-1170.
3. Agostino, A., Pellizzi, E., Aceto, M., Castronovo, S., Saroni, G. and Gulmini, M., 2021. On the hierarchical use of colourants in a 15th century book of hours. Heritage, 4(3), pp.1786-1806.
4. Salvemini, F., Barzagli, E., Grazzi, F., Picollo, M., Agostino, A., Roselli, M.G. and Zoppi, M., 2018. An in situ non-invasive study of two Tibetan manuscripts from the Asian Collection of the Museum of Natural History in Florence. Archaeological and Anthropological Sciences, 10(8), pp.1881-1901.