Identification of Synthetic Organic Pigments in Contemporary Artists' Paints by FT-IR and FT-Raman: An Advanced Analytical Experiment

The identification of coloring substances is a relevant task in the field of conservation and restoration, but it can be challenging as in real samples the target analytes are inserted in a very complex matrix made of binders and additives. Understanding this concept is fundamental for upper-division undergraduate students interested in conservation science; therefore, this laboratory experiment aims to make students aware of this problem and leads them to develop a simple protocol combining two spectroscopic techniques, FT-IR and FT-Raman, and basic chemical treatments to overcome this difficulty. The case of the two quinacridone pigments, PR122 and PV19, is presented and discussed, although the same approach can be extended to other commercially available organic pigments.