Development of extraction methodology for identification of extractive-compounds indexing natural durability of selected wood species

This study is concerned with establishing a uniform experimental protocol for the determination of phenolic extractives, which play an essential role in the durability of the wood of selected species included in the field tests. European larch (Larix decidua), Norway spruce (Picea abies), Scots pine (Pinus sylvestris), European oak (Quercus sp.), sweet chestnut (Castanea sativa), and black locust (Robinia pseudoacacia) were included in the study. Extraction yield data were collected for extraction in a Soxhlet apparatus using common polar extraction solvents (ethanol, acetone, methanol, water) and for single static extraction cycles in accelerated solvent extraction (ASE). The suitability of the solvents and the appropriate extraction conditions were evaluated based on the results of gravimetric analysis of hydrophilic extractives, spectrophotometric analysis of total phenols, and chromatographic analysis using high-performance liquid chromatography. Extraction in the ASE system with methanol proved to be a quick and accurate way to prepare samples for chemical analysis of extractives of selected wood species. With the chemical monitoring of targeted phenolic extractives in wood subjected to leaching, we propose a novel protocol suitable also for for measuring the effects of weathering on the natural durability of wood in future studies.

Automated summary

This study aims to establish a uniform experimental protocol for determining the phenolic extractives in wood that play a crucial role in its durability. Various wood species including European larch, Norway spruce, Scots pine, European oak, sweet chestnut, and black locust were included in the study. Extraction yield data were collected using different solvents and extraction methods, and the suitability and appropriate conditions were evaluated based on gravimetric, spectrophotometric, and chromatographic analysis. The results showed that extraction with methanol using accelerated solvent extraction was a fast and accurate method for preparing samples for chemical analysis. Additionally, a novel protocol for measuring the effects of weathering on wood durability was proposed.