Analytical and bioanalytical chemistry

Identification of lipid- and protein-based binders in paintings by direct on-plate wet chemistry and matrix-assisted laser desorption ionization mass spectrometry.

PMID 25433687


Direct on-target plate processing of small (ca. 100xa0μg) fragments of paint samples for MALDI-MS identification of lipid- and protein-based binders is described. Fragments were fixed on a conventional stainless steel target plate by colloidal graphite followed by in situ fast tryptic digestion and matrix addition. The new protocol was first developed on paint replicas composed of chicken egg, collagen, and cow milk mixed with inorganic pigments and then successfully applied on historical paint samples taken from a fifteenth century Italian panel painting. The present work contributes a step forward in the simplification of binder identification in very small paint samples since no conventional solvent extraction is required, speeding up the whole sample preparation to 10xa0min and reducing lipid/protein loss.