A simple protocol for Matrix Assisted Laser Desorption Ionization- time of flight-mass spectrometry (MALDI-TOF-MS) analysis of lipids and proteins in single microsamples of paintings.

A simple protocol, based on Bligh-Dyer (BD) extraction followed by MALDI-TOF-MS analysis, for fast identification of paint binders in single microsamples is proposed. For the first time it is demonstrated that the BD method is effective for the simultaneous extraction of lipids and proteins from complex, and atypical matrices, such as pigmented paint layers. The protocol makes use of an alternative denaturing anionic detergent (RapiGest™) in order to improve efficiency of protein digestion and purification step. Detection of various lipid classes, such as triacylglycerols (TAGs) and phospholipids (PLs), and their oxidation by-products was accomplished, whereas proteins could be identified by peptide mass fingerprinting. The effect of pigments on ageing of lipids and proteins was also investigated. Finally, the proposed protocol was successfully applied to the study of a late-15th century Italian panel painting allowing the identification of various proteinaceous and lipid sections in organic binders, such as egg yolk, egg white, animal glue, casein, and drying oil.

Characterisation of permanent markers by pyrolysis gas chromatography-mass spectrometry.

Pyrolysis gas chromatography-mass spectrometry (PyGC-MS) was used as a rapid method for the characterization of permanent marker ink. Twenty-four samples of various colours purchased from different manufacturers were characterised. Four main typologies of polymer-binding medium could be distinguished on the basis of the pyrolysis products, and differentiation between permanent markers of different manufacturers could be accomplished. For some permanent marker samples, PyGC-MS analysis allowed pigment identification as well.