A simple method for labelling and detection of proteinaceous binders in art using fluorescent coumarin derivatives

Abstract

The identification of protein binders used in easel paintings is an important information to understand an artist’s technique and for making informed conservation and restoration decisions. The present work presents a novel fluorescent labelling methodology, using a coumarin derivative chromophore, C392STP (sodium (E/Z)-4-(4-(2-(6,7-dimethoxy-coumarin-3-yl) vinyl) benzoyl)-2,3,5,6- tetrafluorobenzenesulfonate), as a fluorophore probe to bond proteinaceous binders used in paintings, followed by separation and identification with protein patterns, by electrophoretic processes. Additionally, theoretical quantum chemical calculations based on density functional theory (DFT) and time-dependent density functional theory (TDDFT) have been performed in a coumarin derivative, which mimics the coumarin bound to the proteins. The optimized methodology was tested on proteinaceous binder extracted from paint model micro-samples. The results evidence the applicability of this methodology as an effective and useful analytical tool for the identification of protein binders obtained from easel paintings.