Disclosing the composition of historical commercial felt-tip pens used in art by integrated vibrational spectroscopy and pyrolysis-gas chromatography/mass spectrometry

In this work the formulation of 20 Johann Faber felt-tip pens commercialized in the 1960s and belonging to and used by the architect and designer Lina Bo Bardi have been investigated by an integrated analytical methodology. Minimally destructive vibrational spectroscopic methods permitted a qualitative interpretation of constituents which could be corroborated and ulteriorly supplemented by more destructive chromatographic techniques. This combined approach constitutes an effective collaboration for an in-depth study chronicling the chemical characterization of the first era of commercially viable felt-tip pen inks by providing for the identification of dyes and separation of their mixtures (triarylmethanes, xanthenes, indigoids, azo dyes, azines), binders (plant gums) and additives (diethylene glycol, phenols/antioxidant, diisoctyl phthalate/plasticizer). The comparison between the early and more recent commercial felt-tip pens has allowed to differentiate dyes, pigments and binders, which may provide a useful reference for future studies on the chemical characterization of historical samples.