Rapid quantification of major reaction products formed during thermochemical pretreatment of lignocellulosic biomass using GC–MS

Accurate quantification of reaction products formed during thermochemical pretreatment of lignocellulosic biomass would lead to a better understanding of plant cell wall deconstruction for production of cellulosic biofuels and biochemicals. However, quantification of some process byproducts, most notably acetamide, acetic acid and furfural, present several analytical challenges using conventional liquid chromatography methods. Therefore, we have developed a high-throughput gas chromatography based mass spectrometric (GC–MS) method in order to quantify relevant compounds without requiring time-consuming sample derivatization prior to analysis. Solvent extracts of untreated, ammonia fiber expansion (AFEX) treated and dilute-acid treated corn stover were analyzed by this method. Biomass samples were extracted with acetone using an automated solvent extractor, serially diluted and directly analyzed using the proposed GC–MS method. Acetone was the only solvent amongst water, methanol and acetonitrile that did not contain detectable background levels of the target compounds or facilitate a buildup of plant-derived residues in the GC injector, which decreased analytical reproducibility. Quantitative results were based on the method of standard addition and external standard calibration curves.