Characterization of lignin by gas capillary chromatography of cupric oxide oxidation products

A sensitive, reproducible method is described for the characterization of lignin in untreated plant and geochemical samples containing 10 mg or less organic matter. The whole sample is treated with alkaline cupric oxide at 170 degrees to produce simple lignin- derived phenols that are extracted with ethyl oxide and analyzed by gas capillary chromatography on fused silica columns. A pattern of 11 or less phenols is produced that reflects the relative concentration and plant tissue sources of lignins present in the sample.