Qualitative analysis of bio oils of agricultural residues obtained through pyrolysis using comprehensive two dimensional gas chromatography with time-of-flight mass spectrometric detector

Abstract

The use of bio oil of fast pyrolysis of agricultural and industrial residues may be an economically and environmentally friendly choice for generation of energy and also for the production of chemicals. Suitable applications of rice husk and peach pit are an important issue to avoid improper waste disposal, as Brazilian production of rice and peach reach significant values. The purpose of this work was to perform a detailed qualitative analysis of bio oils of rice husk and peach pit, taking advantage of the higher peak capacity, resolution, sensitivity and selectivity of two-dimensional gas chromatography with mass spectrometric detector (GC×GC/TOFMS). The total number of compounds detected by GC×GC/TOFMS was 503 and 705 for rice husk and peach pit pyrolysates, respectively. Compounds tentatively identified in the same matrices were 106 and 223, respectively. Bio oil compounds were classified in five groups: phenols ketones, acids, ethers, aldehydes, and others. Major classes of both bio oils were phenols and ketones and the major compounds of rice husk and peach pit pyrolysates were guaiacol and furfural, respectively. Twenty compounds (area>1%) of rice husk bio oil and 25 of peach pit oil accounted for 74.04% and 63.62% of the total area, respectively. A structured distribution of compounds of some classes was observed in the two dimensional space, as for example phenols and ketones. Qualitative analysis of these bio oils by GC×GC provided a detailed knowledge of their composition. Both bio oils showed might be employed for the production of chemicals and may be upgraded through an improved pyrolysis process.