Simple Milligram-Scale Extraction of Formaldehyde from Wood

Abstract

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 μg/g dry wood, and were comparable to published values using the perforator method. Heating at 200° 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.

Influence of Lignin Content and Pressing Time on Plywood Properties Bonded with Cold-Setting Adhesive Based on Poly (Vinyl Alcohol), Lignin, and Hexamine

“…No remarkable effect was observed for FE values at different contents of lignin and different pressing times. The resulting FE could be the biogenic formaldehyde originating from wood, which was in agreement with the published works [ 71 , 72 , 73 , 74 , 75 ]. It is well acknowledged that wood contains biogenic formaldehyde from lignin.…”

Lignin Acidolysis Predicts Formaldehyde Generation in Pine Wood

“…Saturated specimens were subsequently adjusted to 100% moisture content. Heat treatments were conducted in sealed 50 mL serum bottles for 10 or 60 min . The CH 2 O generated during heating remained sealed in the serum bottle and was determined as described previously .…”

“…In the living tree or otherwise, wood contains natural, biogenic formaldehyde (CH 2 O), defined here as having a carbon source in wood; and heating generates much higher levels that vary according to wood moisture content, tissue type, and tree species. − Biogenic CH 2 O levels vary dramatically for reasons not understood. For instance, Tasooji et al demonstrated that Pinus radiata generates 2–6 times more CH 2 O than does Liriodendron tulipifera and Pinus virginiana when heated at 200 °C (10 min) .…”

Formaldehyde from Lignin Acidolysis Might Be Useful for In-Line Control of Industrial Biomass Processing

“…The formaldehyde content of unextracted samples (about 30 mg) was measured as described. , Note that formaldehyde gaseous emissions were not measured; instead the formaldehyde retained in the processed fiber was measured by water extraction, generally as follows. Specimens were sealed in clean, dry serum bottles (crimped aluminum cap with silicone septa) under dry N 2 .…”