Analysis of phenols in pyrolysis oils by gel permeation chromatography and multidimensional liquid chromatography

A simple method with minimal manual sample preparation was developed for the analysis of phenols in pyrolysis oils. Sample pre-treatment was done by gel permeation chromatography (GPC), where the high-molecular-mass lignins were separated from the phenols. Multidimensional liquid chromatography (LC-LC) was used in the analysis of the phenolic fraction. The pre-column was used for sample clean-up and pre-fractionation before introduction of the phenolic fraction to the analytical column. The repeatability and linearity of the total GPC and LC-LC methods were excellent. The results were in accordance with the reference method in which the sample pre-treatment was done by precipitating the lignins with water, and the phenols were extracted with toluene and analysed by GC-MS.