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

Abstract

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.

Polyphenolic compounds with biological activity in guabiroba fruits (Campomanesia xanthocarpaBerg.) by comprehensive two‐dimensional liquid chromatography

“…Finally, calculate the "corrected" peak capacity achieved, considering both orthogonality and undersampling, the maximum limit of 522 peaks for unripe guabiroba and 418 peaks for ripe guabiroba, were attained. Similar values were obtained by Montero et al [25], Arena et al [26], and Lazzari et al [27] employing RP-LC×RP-LC…”

Evaluation of matrix effect in one‐dimensional and comprehensive two‐dimensional liquid chromatography for the determination of the phenolic fraction in extra virgin olive oils

“…As viable alternative for enhancing the overall separation capability, comprehensive 2D‐LC (LC × LC) has been far employed for phenol determination in many food and natural products as witnessed by several recent research and review articles [21–34]. It was already reported that LC × LC minimize matrix interferences at the detector, because of the higher resolving power, viz .…”

Comprehensive two‐dimensional liquid chromatography‐based quali‐quantitative screening of aqueous phases from pyrolysis bio‐oils

“…Phenolic compounds and aldehydes are mainly derived from lignin and cellulose degradation, respectively [39]. Benzenediols, derived from lignin degradation, remain mainly in the aqueous phase while other phenols, such as alkyl and methoxyphenols, are commonly found in higher concentration in the bio‐oils [18,40]. 5‐(Hydroxymethyl) furfural, 5‐methylfurfural, and furfural are the main compounds formed from cellulose thermal degradation [39] and were identified in all aqueous samples, though with different concentrations levels.…”

“…Method performance was evaluated through the assessment of the main figures of merit: dynamic range, linearity, limits of detection and quantification, precision (intra‐ and interday) and accuracy (by recovery). All the validation procedure was according ANVISA [31] protocols as previously reported in detail [18].…”

“…To overcome this problem, comprehensive twodimensional liquid chromatography (LC × LC) may be a useful analytical tool, considering that aqueous phases are normally composed of a high number of compounds, some of them closely related and, thus, very difficult to be separated [16][17][18][19]. Besides, LC × LC allows the injection of the whole sample without any sample preparation steps, and retains a significantly higher separation power providing very high peak capacity compared to conventional one-dimensional LC separations [20][21][22].…”