Rapid Separation and Quantitative Analysis of Complex Lipophilic Wood Pulp Extractive Mixtures Based on 2D Thin Layer Chromatography

We present a rapid method based on 2D thin layer chromatography (TLC) for the simultaneous separation and quantification of organic, lipophilic extractives occurring in lignocellulosic biorefineries. The separation is based on alkaline followed by acidic elution for a 2D separation of the different compound classes (sterols, fatty alcohols, fatty acids, and resin acids). Staining with Nile Blue A and subsequent scanning and image analysis of the plates provides quantitative information on the concentration of each compound class. Correlation coefficients between 0.92 (abietic acid, resin acid) and 0.98 (β-sitosterol, sterol) are determined in these experiments. Besides the analysis of the composition, this procedure indicates the relative polarity as the acidity or basicity of the constituents. TLC results of an industrial lipophilic extractives sample correlate with state-of-the-art GC × GC–MS measurements with differences being in the range between 0.5 (fatty alcohols) and 6% (resin acids), respectively.