Understanding the Changes to Biomass Surface Characteristics after Ammonia and Organosolv Pretreatments by Using Time-of-Flight Secondary-Ion Mass Spectrometry (TOF-SIMS)

Surface characteristic changes to poplar after ammonia and organosolv pretreatments were investigated by means of time-of-flight secondary-ion mass spectrometry (TOF-SIMS) analysis. Whereas normalized total polysaccharides and lignin contents on the surface differed from bulk chemical compositions, the surface cellulose ions detected by TOF-SIMS showed the same value trend as the cellulose content in the biomass. In addition, the lignin syringyl/guaiacyl ratio according to TOF-SIMS results showed the same trend as the ratio measured by means of NMR spectroscopic analysis, even though the ratio scales for each method were different. A similar correlation was determined between the surface cellulose and glucose release after enzymatic hydrolysis. These results demonstrate that surface characterization using TOF-SIMS can provide important information about the effects of pretreatment on biomass properties and its hydrolysis.