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 makes it possible to discriminate different phases and polymorphs, as well as to 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 a 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 B&W Tek 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 operates 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 40× 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 setup at the Biblioteca Nazionale Vittorio Emanuele III of Naples.

References

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.
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, 37(10), pp.1160-1170.
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.
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.

Keywords: Portable Raman spectroscopy