Quality control of natural resins used in historical European lacquer reconstructions with some reflections on the composition of sandarac resin (Tetraclinis articulata (Vahl) Mast.)

In order to verify correct labeling and purity of natural lacquer ingredients sold today, 66 resins, gums and oils were analyzed by THM-GC/MS and compared with non-commercial reference samples. 21 deviations were found, indicating an adulteration or mislabeling of a resin. Many of the deviations occurred in sandarac resin, traditionally harvested from Tetraclinis articulata (Vahl) Mast., which seems to have another composition today than historically. Differences between both types were persistent through artificial aging. This study comprised one freshly harvested sandarac resin, as well as several specimens of historical collections, as reference material for Tetraclinis articulata. The currently sold sandarac was compared with the Tetraclinis articulata references, and with resins from the genera Agathis, Juniperus and Callitris, but its botanical source was not revealed.