Quantitative analysis of aqueous phases of bio-oils resulting from pyrolysis of different biomasses by two-dimensional comprehensive liquid chromatography

Agrifood by-products are perfect candidates to be further processed under the concept of circular economy, in order to produce their valorization. Although significant amounts of food-related wastes that are discarded are produced worldwide, these might still be rich in valuable compounds. A strategy to further valorize agrifood-related by-products is based on pyrolysis processes. The result of this process is a liquid product termed bio-oil which is composed of an organic phase and an aqueous phase. This bio-oil is rich on a variety of components and its analysis implies several challenges. In this work, quantitative on-line comprehensive two-dimensional liquid chromatography (LC × LC) is proposed for the first time to characterize several aqueous phases of different bio-oils. Rice husk, peanut shell, spent coffee grounds, peach core and Eucalyptus sawdust biomasses were analyzed. The developed quantitative LC × LC method presented very good linearity, precision, reproducibility, recovery and LODs and LOQs as low as 0.05 μg mL−1 and 0.16 μg mL−1, respectively. As much as 28 components were simultaneously separated and quantified in those samples. Our results found that the composition of these bio-oils was different but strongly related to the agrifood by-product submitted to pyrolysis. The developed methodology is foreseen as a valuable tool for the quantitative study of other bio-oils, considering the great complexity and high dimensionality of these samples.Authors thank Projects AGL2017-89417-R (MINECO, Spain) and iLINK+ 1096 (CSIC, Spain) for funding. Eliane Lazzari thanks CNPQ (Conselho Nacional de Desenvolvimento Científico e Tecnológico) for the scholarship and FINEP (Financiadora de Estudos e Projetos) and Petrobras for financial support. Katia Arena thanks “Prof. Antonio Imbesi Foundation” of the University of Messina for the financial support.Peer reviewe