Detailed characterization of red oak-derived pyrolysis oil: Integrated use of GC, HPLC, IC, GPC and Karl-Fischer

Red oak bio-oil obtained from fast pyrolysis in a fluidized bed reactor was fully analyzed using gas chromatography/mass spectrometry (GC/MS), high-performance liquid chromatography (HPLC), ion chromatography (IC), gel permeation chromatography (GPC) and Karl-Fischer titration. Based on the chemical speciation, we achieved a high mass balance closure of bio-oil (92 wt%). Of the analytical techniques, GC accounted for the largest portion of the bio-oil (25.7 wt%), followed by HPLC (15.4 wt%) and IC (8.1 wt%). Monosaccharides and disaccharides (not detected by GC) were characterized by HPLC, and total sugars present in bio-oil were estimated by running acid-hydrolysable sugars in the HPLC. Quantity of pyrolytic lignin, oligomer of lignin-derived phenolic compounds, was determined as a GC-undetected portion of water-insolubles of a whole bio-oil. Small standard deviation of each compound between duplicate runs indicated a reproducibility of pyrolysis experiments and bio-oil characterizations validating the detailed analytical approach used.