The Development and Initial Application of a Gas Chromatographic Method for the Characterization of Gum Media

This article details the initial investigations into the development and application of a simple, "one-pot" hydrolysis and derivatization procedure for the characterization of natural gum-based artists' binding media. Samples were hydrolyzed under acid conditions, then silylated with hexamethyldisilazane (HMDS). Separation and analysis of the volatile monosaccharide derivatives were achieved by gas chromatography-mass spectrometry (GC-MS) with selected ion monitoring (SIM). A selection of standard gum media was analyzed using this method, and a small number of suspected gum media samples taken from William Blake's temperas were characterized thus: results frequently indicated the presence of mixed gum media (commonly containing gums tragacanth, karaya, and arabic) with added cane sugar.