PEG-migration? MALDI-TOF-analys av beläggningar från fyra arkeologiska träföremål

Abstract

One of the most important tasks in conservation of archaeological wood is to maintain its shape and stability. This is often done by replacement of the water within the wood-cells. Polyethylene glycol (PEG) is a synthetic polymer which has been widely used in the field of conservation for this purpose. PEG is hygroscopic and treated objects are for that reason sensitive to environments of high and unstable relative humidity. The purpose of this study is to investigate if the phenomenon of migrated PEG was observed on the surfaces of four conserved archaeological wooden objects. It appeared as light precipitates and were examined by Matrix Assisted Laser Desorption/Ionization-Time Of Flight (MALDI-TOF). This technique provides information about the molecular weight of the material analyzed. Analyses of precipitates from one of the objects (2469) indicate similarities with that of the reference sample PEG 400. The result indicates PEG-migration. The analyses of the precipitates from the other three objects (35, 1774, 1787) did not have similarities with the reference samples of PEG 400, PEG 1500 nor PEG 4000. The phenomenon of PEG-migration is not well-investigated and described in the literature as a waxy transparent fluid. However, the migrated PEG 400 in this case appeared as white precipitates which are not as fluid.