Portable FT-IR spectroscopy

Fourier Transform Infrared spectroscopy (FT-IR) is a technique that allows identifying a wide range of organic (binders, paints, adhesives, etc.) and inorganic compounds (pigments, salts, degradation products, etc.) through the analysis of their functional and molecular groups. It is widely used to characterize the components of an artefact, as well as identify the materials used for conservation purposes and their alteration products. FT-IR also provides useful information for an assessment of the conservation status of the work under investigation.

In the framework of the present study, a portable Alpha Bruker Optics FT-IR Spectrophotometer from the CNR-IFAC Sabec laboratories was used. It allows acquiring spectra in Total Reflectance mode in a non-invasive way. The spectrometer consists of a globar-type infrared source (silicon carbide with emission comparable to that of a black body at a temperature of approximately 1000 K), an interferometer, a DTGS (tridiglycinsulphate deuterate) pyroelectric detector, with a resolution of 4 cm-1 and sensitivity in the spectral range (375-7500 cm-¹) comprising the entire mid-infrared region (MIR, 4000-400 cm-1), as well as part of the near-infrared (NIR, 7500-4000 cm-1) and of the far-infrared (FIR, 400-375 cm-1). EZ OMNIC 7.3 and SpectraGryph 1.2 software were used for data processing. The identification of the materials was carried out by comparison with reference spectra found in literature databases or made at CNR-IFAC laboratories.

The spectrophotometer is also equipped with different plug and play modules for collecting spectra in transmittance and Attenuated Total Reflectance (ATR) modes. The compact design of the spectrophotometer makes it possible to successfully work in-situ.

CNR-IFAC Alpha Bruker Optics FT-IR Spectrophotometer setup at the Biblioteca Nazionale Vittorio Emanuele III of Naples.

References

1. Aceto, M., Agostino, A., Fenoglio, G., Gulmini, M., Bianco, V. and Pellizzi, E., 2012. Non invasive analysis of miniature paintings: proposal for an analytical protocol. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 91, pp.352-359.
2. Bartolozzi, G., Picollo, M., Marchiafava, V., Centeno, S.A., Duvernois, I., Di Girolamo, F., Modugno, F., La Nasa, J., Colombini, M.P. and Rava, A., 2016. Anselm Kiefer: a study of his artistic materials. Archaeological and Anthropological Sciences, 8, pp.563-574.
3. Carlesi, S., Bartolozzi, G., Cucci, C., Marchiafava, V. and Picollo, M., 2013. The artists’ materials of Fernando Melani: a precursor of the Poor Art artistic movement in Italy. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 104, pp.527-537.
4. Cucci, C., Bartolozzi, G., Marchiafava, V., Picollo, M. and Richardson, E., 2016. Study of semi-synthetic plastic objects of historic interest using non-invasive total reflectance FT-IR. Microchemical Journal, 124, pp.889-897.