Degradation of polyethylene glycol and hemicellulose in the Vasa

Mass spectrometric analysis of aqueous wood extracts from the Swedish warship Vasa reveals a serious chemical condition in the depth of the wood. The surface is less affected. Polyethylene glycol, used as conservation agent, is affected and partly degraded, and low-molecular fragments from hemicellulose are found at sites with high iron content and low pH. These findings imply a catalytic oxidative process and acidic hydrolysis in the wood, which contributes to a new picture of the challenge of long-term preservation of the Vasa.