Fast pyrolysis of biomass is a relatively simple and scalable process with high carbon recovery. However, the low quality and instability of the resulting bio-oil limit its utility. Upgrading is hindered by bio-oil's enormous complexity, which arises from a multitude of unknown primary, secondary and later reactions during fast pyrolysis.In the previous study, we focused on detecting the primary products of lignin fast pyrolysis. A fast pyrolysis probe was coupled with a linear quadrupole ion trap mass spectrometer. Atmospheric-pressure chemical ionization (APCI) with ammonium hydroxide dopant was used to ionize and characterize the primary products of lignin fast pyrolysis.In this study, direct injection of lignin model compounds through heated APCI source is found to mimic the primary products obtained from fast pyrolysis. The synthetic model compounds range from trimers to octamers with �-O-4 and/or 5-5 linkages. Heated APCI source was able to induce fragmentation of lignin oligomers, generating similar fragmentation products as to those observed in fast pyrolysis, especially for �-O-4 linkage lignins. However, APCI heating alone may not cleave 5-5 linkages of lignins. Besides vaporizing temperature, sample flow rate was optimized to generate pyrolysis-like products. Overall,300C, 30-100 ul/min or400C, 50-100 ul/min were chosen. The results show that the major fragmentation products are dimers, monomers, trimers and tetramers, which are consistent with the previous findings. In summary, heated APCI source in mass spectrometry may provide an alternative method to predict fast pyrolysis patterns of small lignin molecules with �-O-4 linkages.

Mimicking fast pyrolysis of lignin �-O-4 oligomers by heated APCI source in mass spectrometry

248th National Meeting (2014)

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