Determination of the accessible hydroxyl groups in heat-treated Styrax tonkinensis (Pierre) Craib ex Hartwich wood by hydrogen-deuterium exchange and 2H NMR spectroscopy

A new approach based on hydrogen-deuterium exchange is proposed for measuring accessible OH groups in wood. The deuterium (D) exchanged for hydrogen in OH groups in wood was converted to D2O by combustion in oxygen gas then diluted in deionized water, and subsequently determined by 2H NMR spectroscopy. The amount of accessible OH groups in Styrax tonkinensis wood is approximately 6.8 mmol g-1. This measurement is very accurate, with an error of approximately 0.2 mmol g-1. Heat-treated wood has a lower amount of accessible OH groups than non-treated wood. This finding is in agreement with the decreased hygroscopicity of heat-treated wood and explains, at least partially, its increased fungal resistance.