Assessing the chemical composition of bio-oils using FT-ICR mass spectrometry and comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry

Bio-oils were obtained from the flash-pyrolysis of empty palm fruit bunch and pine wood chips. They were analyzed by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI(-)-FT-ICR MS) and comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC x GC-TOFMS), in order to provide a complementary and comprehensive characterization of the bio-oils. ESI(-)-FT-ICR MS detected high-oxygen content compounds, with m/z values ranging from 150 to 700, resulting in percentages of assignable peaks higher than 80% (composed of heteroatom classes from O-2 to 014 with a carbon number of C-6-C-27 and a double bond equivalent [DBE] of 1-14). All assignable signals showed ultrahigh resolution and accuracy mass (mean of mass error lower than 0.05 ppm). Some low-oxygen content classes inaccessible by ESI-FT-ICR MS were identified by GC x GC-TOFMS (classes from O-0 to O-8 with a carbon number of C-3-C-14). The chemical characterization of the bio-oils combining the high chromatographic resolution power of GC x GC-TOFMS (detecting volatile compounds) with the high dynamic range of m/z of FSI-FT-ICR MS allowed identification of polar, volatile and nonvolatile compounds. Detailed information on the composition of these oils is very important when upgrading to second-generation biofuels and when using the oils as a base for chemicals. (C) 2014 Elsevier B.V. All rights reserved.