THE DETERMINATION OF POLYETHLYLENE GLYCOL AND WATER IN ARCHAEOLOGICAL WOOD USING INFRARED SPECTROSCOPY AND STEPWISE MULTIPLE LINEAR REGRESSION

Polyethylene glycol (PEG) is the most common preservative in use for bulking and maintaining structural integrity in waterlogged wood. Conservators therefore have a need to be able to determine PEG concentrations in wood in a non-destructive manner. We present a study highlighting the application of infrared spectroscopy coupled with multivariate analysis techniques to predict the concentration of polyethylene glycol 400 (PEG-400) and water simultaneously. This technique uses attenuated total reflectance (ATR) spectroscopy and unconstrained stepwise multiple linear regression (SMLR) analysis for prediction of multiple components in archaeological wood. Using this model we have calculated the concentration of PEG-400 and water in treated archaeological waterlogged wood samples.