The increasing energy demand along with depleting conventional energy sources requires efficient utilization of alternative sources of energy. The pyrolysis of biomass is a reliable means of conversion to potentially useful products, such as bio-oils, which can be catalytically upgraded to efficient fuel. A primary aim in bio-oil research is to develop suitable techniques for pyrolysis and catalytic upgrading to make the production of biofuel cost�effective. Currently, progress is hindered by a poor understanding of bio�oil composition at the molecular level. Information from analyses of bio-oil by conventional techniques is limited to either bulk properties (e.g., averaged functional group identification of the bulk bio-oil by nuclear magnetic resonance) or volatile compounds (by gas chromatography � mass spectrometry). Recently, the use of high resolution mass spectrometry (HRMS) has been reported as a suitable technique for detailed molecular characterization of bio-oils. However, results from HRMS analyses have been limited to mostly fast pyrolysis generated bio-oils from few feedstock types. Here, we present the first application of HRMS to the analysis of bio�oils (oily and aqueous fraction) generated by the slow pyrolysis of plant biomass. Analyte ion signal was observed primarily between m/z 70 and 450 in the mass spectra of these samples. The complex composition of bio-oils was demonstrated by the presence of hundreds of unique peaks in the mass spectra. Unique elemental compositions were assigned to the majority of those peaks by exact mass analysis. Elemental compositions having high oxygen content and high DBE values were found to be prevalent in these samples. Higher average oxygen content per molecule was observed in aqueous fractions compared to oily fractions. Mass defect analysis suggested the presence of a large number of overlapping CH2 homologous series between oily and aqueous fractions.

Analysis of slow-pyrolysis bio-oils generated from plant biomass by negative electrospray ionization-high resolution mass spectrometry

246th National Meeting (2013)

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