Simple Milligram-Scale Extraction of Formaldehyde from Wood

Lignocellulose naturally contains formaldehyde, and generates much more when heated. A simple quantitation of such biogenic formaldehyde is desirable for the analysis and utilization of lignocellulose. Heretofore, a boiling toluene extraction (the perforator method) was the best known technique to determine biogenic formaldehyde in wood. Described here is a simple milligram-scale water extraction that avoids specimen heating. This method was validated by comparison to a laborious extraction using poly(allylamine), PAA, beads that strongly sorb formaldehyde. The PAA-based extraction and the water-only extraction were found to be effectively equivalent, recovering about 94% of wood formaldehyde. The incomplete formaldehyde recovery is offset by experimental simplicity, and suitability for large sampling. For instance, the new method was applied to the analysis of tree increment cores; formaldehyde levels measured in never-heated Pinus virginiana ranged from 1 to 5 mu g/g dry wood, and were comparable to published values using the perforator method. Heating at 200 degrees for 10 min generated about 10-20 times more biogenic formaldehyde. This simple extraction is useful to document biogenic formaldehyde levels in wood, and the formaldehyde generation potential associated with heating, as in the manufacture of wood-based composites.