Microwave and ultrasound extraction of antioxidant phenolic compounds from Lantana camara Linn. leaves: Optimization, comparative study, and FT-Orbitrap MS analysis.

INTRODUCTION: The species Lantana camara is used in folk medicine. The biological activities of this medicinal plant are attributable to the presence of various derivatives of triterpenoids and phenolic compounds present in its preparations, indicating excellent economic potential. OBJECTIVE: In this study, the operational conditions of ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) were optimized using Box-Behnken design to improve the total phenolic content (TPC) recovered in hydroethanolic extracts of L. camara leaves. MATERIAL AND METHODS: The TPC, total flavonoid content (TFC), and antioxidant activities of the hydroalcoholic extracts of L. camara, prepared by UAE and MAE under the optimized extraction conditions, were compared with those of the extracts obtained by conventional extraction methods. RESULTS: Under the optimal conditions, the extracts obtained by UAE (35% ethanol, 25 min, and a solvent-to-solid ratio of 60:1 mL/g) and by MAE (53% ethanol, 15 min, and 300 W) provided high yields of 32.50% and 38.61% and TPC values of 102.89 and 109.83 mg GAE/g DW, respectively. The MAE extract showed the best results with respect to TPC, TFC, and antioxidant activities, followed by extracts obtained by UAE, Soxhlet extraction, decoction, maceration, and infusion, in that order. CONCLUSION: The results obtained indicate that L. camara may be used as an important source of antioxidant phenolic compounds to obtain products with high biological and economic potential, especially when the extraction process is performed under appropriate conditions using MAE and/or UAE, employing environmentally friendly solvents such as water and ethanol.

Multiple reaction monitoring tool applied in the geochemical investigation of a mysterious oil spill in northeast Brazil.

In 2019, much of the northeastern coast of Brazil was impacted by a mysterious oil spill that caused an environmental disaster affecting 1009 beaches. Four samples were collected in the beaches between Sergipe and Pernambuco for geochemical characterization of the spilled oil and to compare with those main produced in Sergipe-Alagoas basin. Our approach in this evaluation was the use of a highly selective technique of sequential mass spectrometry by multiple reaction monitoring, to obtain the diagnostic ratios of hopanes and steranes biomarkers. Using these biomarkers ratios associated with multivariate statistical analysis, we found direct correlation between the spilled oil collected along the northeastern coast and no relationship between Sergipe-Alagoas basin crude oils was found. Furthermore, reported data for oils from Orinoco belt in Venezuelan basins were used for qualitative evaluation considering the indicative aspects suggested by the literature. Presence of highly specific biomarker 18α(H)-oleanane, and five other important diagnostic ratios evidenced correlation between the spilled oil and Naricual formation crude oils. Besides, due to the oleanane index, Ayacucho's crude oil presented the strongest factor of correlation with the spilled oil found on the northeast coast of Brazil.

Continuous rotary kiln pyrolysis of cassava plant shoot system and wide speciation of oxygenated and nitrogen-containing compounds in bio-oil by HESI and APPI-Orbitrap MS.

This work proposes the pyrolysis of the cassava plant shoot system biomass and a comprehensive chemical characterization of the resulting bio-oil. The highest yields of liquid products were obtained at 600 °C, with 12.6 % bio-oil (organic fraction), which presented the lowest total acid number of 65.7 mg KOH g-1. The bio-oil produced at 500 °C exhibited the highest total phenolic content of approximately 41 % GAE, confirmed by GC/MS analysis (33.8 % of the total area). FT-Orbitrap MS analysis found hundreds of oxygenated constituents in the bio-oils, belonging to the O2-7 classes, as well as nitrogen compounds from the Ny and OxNy classes. Higher pyrolysis temperatures resulted in more oxygenated phenolics (O4-7) undergoing secondary degradation and deoxygenation reactions, generating O2-3 compounds. Additional classes affected were O3-5N2-3, while O1-2N1 presented more stable compounds. These findings show that cassava bio-oils are promising sources of renewable chemicals.

Chemical evaluation of pyrolysis oils from domestic and industrial effluent treatment station sludges with perspective to produce value-added products.

The use of renewable sources for energy has increased due to the high demand of modern society and the environmental impacts caused by the use of fossil fuels. Environmentally friendly renewable energy production may involve thermal processes, including the application of biomass. We provide a comprehensive chemical characterization of sludges from domestic and industrial effluent treatment stations, as well as the bio-oils produced by fast pyrolysis. A comparative study of the sludges and the corresponding pyrolysis oils was performed, with characterization of the raw materials using thermogravimetric analysis, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, elemental analysis, and inductively coupled plasma optical emission spectrometry. The bio-oils were characterized using comprehensive two-dimensional gas chromatography/mass spectrometry that identified compounds classified according to their chemical class, mainly related to nitrogenous (62.2%) and ester (18.9%) for domestic sludge bio-oil, and nitrogenous (61.0%) and ester (27.6%) for industrial sludge bio-oil. The Fourier transform ion cyclotron resonance mass spectrometry revealed a broad distribution of classes with oxygen and/or sulfur (N2O2S, O2, and S2 classes). Nitrogenous compounds (N, N2, N3, and NxOxclasses) were also found to be abundant in both bio-oils, due to the origins of the sludges (with the presence of proteins), making these bio-oils unsuitable for use as renewable fuels, since NOxgases could be released during combustion processes. The presence of functionalized alkyl chains indicated the potential of the bio-oils as sources of high added-value compounds that could be obtained by recovery processes and used for the manufacture of fertilizers, surfactants, and nitrogen solvents.

Assessment of the effect of short-term weathering on the molecular-level chemical composition of crude oils in contact with aquatic environments.

Multiple studies have focused on the effect of long-term weathering processes on oils after spill events, without considering the chemical compositional changes occurring shortly after the release of oil into the environment. Therefore, the present study provides a broad chemical characterization for understanding of the changes occurring in the chemical compositions of intermediate (°API = 27.0) and heavy (°API = 20.9) oils from the Sergipe-Alagoas basin submitted to two simulated situations, one under marine conditions and the other in a riverine environment. Samples of the oils were collected during the first 72 h of contact with the simulated environments, followed by evaluation of their chemical compositions. SARA fractionation was used to isolate the resins, which were characterized at the molecular level by UHRMS. The evaporation process was highlighted, with the GC-FID chromatographic profiles showing the disappearance of compounds from n-C10 until n-C16, as well as changes in the weathering indexes and pristane + n-C17/phytane + n-C18 ratios for the crude oils submitted to the riverine conditions. Analysis of the resins fraction showed that basic polar compounds underwent little or no alterations during the early stages of weathering. The marine environment was shown to be much less oxidative than the riverine environment. For both environments, a feature highlighted was an increase of acidic oxygenated compounds with the increase of weathering, especially for the crude oil with °API = 27.0.

Comprehensive approach of methods for microstructural analysis and analytical tools in lignocellulosic biomass assessment - A review.

The trend in the modern world is to replace fossil fuels with green energy sources in order to reduce their environmental impact. The biorefinery industry, within this premise, needs to establish quantitative and qualitative analytical methods to better understand lignocellulosic biomass composition and structure. This paper presents chemical techniques (chromatography, thermal analysis, HRMS, FTIR, NIR, and NMR) and physicochemical techniques (XRD, optical and electron microscopy techniques - Confocal fluorescence, Raman, SPM, AFM, SEM, and TEM) for the microstructural characterization of lignocellulosic biomass and its derivatives. Each of these tools provides different and complementary information regarding molecular and microstructural composition of lignocellulosic biomass. Understanding these properties is essential for the design and operation of associated biomass conversion processing facilities. PAT, monitored in real-time, ensures an economical and balanced mass-energy process. This review aimed to help researchers select the most suitable analytical technique with which to investigate biomass feedstocks with recalcitrant natures.

Selective carbonaceous-based (nano)composite sensors for electrochemical determination of paraquat in food samples.

A novel electrochemical sensor based on activated biochar (AB4) and reduced graphene oxide (rGO) was developed and tested for detection of paraquat (PQ) in food samples. Precursor biochar was obtained by the pyrolysis of water hyacinth biomass at 400, 500, and 600 °C, followed by a chemical activation step using HNO3 to increase the amount of oxygenated and nitrogenated groups. The modified electrodes (rGO-AB4) were tested in different experimental conditions, and exhibited good response under the optimized conditions, showing linearity from 0.74 to 9.82 µmol L-1 and a limit of detection and limit of quantification of 0.02 µmolL-1 and 0.07 µmol L-1, respectively. Interfering species such as glyphosate caused insignificant changes in the peak current of paraquat, and the selectivity of the method was tested using blank and spiked samples of coconut water, wastewater, honey, lettuce and lemon. Recovery ranged from 87.70±2.07% to 103.80±3.94%.

Assessment of black liquor hydrothermal treatment under sub- and supercritical conditions: Products distribution and economic perspectives.

This study reports an alternative method for black liquor treatment with potential for energy and process savings in the paper and pulp industry. Gasification of black liquor was carried out under sub- and supercritical conditions, varying the black liquor feed composition (0.10, 2.55 and 5.00 wb%) and temperature (350, 425 and 500 °C). Liquid products were identified by high resolution mass spectrometry (FT-Orbitrap MS) and compounds belonging to classes O3 and O4 were found to be the most representative in the products of reactions performed at 500 °C. The mass spectra results also revealed the overall selectivity of reactions, where decarboxylation and demethoxylation reactions were favored under subcritical and supercritical conditions, respectively. Among the gaseous products, hydrogen and methane were produced with maximum of 69.04 and 28.75 mol%, respectively, at 2.55 wb% and 425 °C. The proposed thermodynamic modelling of the reaction system satisfactorily predicted the gas phase behavior of the system. In the economic analysis, the simulated conditions indicated that the main energy requirements for a scaled-up black liquor gasification process are related to the necessary heat exchangers and pressurizing of the black liquor solution. Furthermore, the cost of the black liquor gasification is around 0.06 US$ per kg of feed stream. Liquid and gaseous products from gasification could be obtained at a cost of 56.64 US$ and 3.35 US$ per tonne of stream, respectively. Therefore, black liquor gasification is an interesting route for obtaining combustible gases and value-added bioproducts.

Molecular behavior assessment on initial stages of oil spill in terrestrial environments.

The contamination of terrestrial environments by oil spills creates biological risks to humans and affects the ecosystem's health. The studies that aim to evaluate the toxicity and changes in the environments are a field of potential interest to the scientific community. The objective of this study was to evaluate the changes in the chemical composition of crude oil fractions after the simulation of a spill in soil and sand, with emphasis on an immediate temporal investigation. Samples of intermediate (°API = 27.0) and heavy (°API = 20.9) oils from Sergipe-Alagoas basin were used. The evaporation process in the soil was highlighted; while the GC-FID chromatographic profiles demonstrated (1) the disappearance from n-C12 until n-C14 compounds, besides a decrease of more than 50% in n-C15 and n-C16 n-alkanes and (2) no changes in n-C17/Pr and n-C18/Ph ratios for both oils. Analysis of resins fraction performed by Orbitrap-MS has shown changes in the mass spectra profile and compound distribution during the soil and sand exposure process, with N1, O1, and O2 species showing changes in the relative abundance in ESI(+) mode, and O2, N1, and O1 for ESI(-). Changes in polar compounds of oil will depend on the extent of the time of interaction with soil and sand, taking into account intrinsic aspects, such as the nature of the soil and components in it as the organic matter.

Renewable Hydrocarbon Production from Waste Cottonseed Oil Pyrolysis and Catalytic Upgrading of Vapors with Mo-Co and Mo-Ni Catalysts Supported on γ-Al2O3.

In this work, the production of renewable hydrocarbons was explored by the means of waste cottonseed oil (WCSO) micropyrolysis at 500 °C. Catalytic upgrading of the pyrolysis vapors was studied using α-Al2O3, γ-Al2O3, Mo-Co/γ-Al2O3, and Mo-Ni/γ-Al2O3 catalysts. The oxygen removal efficiency was much lower in non-catalytic pyrolysis (18.0%), whilst γ-Al2O3 yielded a very high oxygen removal efficiency (91.8%), similar to that obtained with Mo-Co/γ-Al2O3 (92.8%) and higher than that attained with Mo-Ni/γ-Al2O3 (82.0%). Higher conversion yields into total renewable hydrocarbons were obtained with Mo-Co/γ-Al2O3 (61.9 wt.%) in comparison to Mo-Ni/γ-Al2O3 (46.6%). GC/MS analyses showed a relative chemical composition of 31.3, 86.4, and 92.6% of total renewable hydrocarbons and 58.7, 7.2, and 4.2% of oxygenated compounds for non-catalytic bio-oil (BOWCSO), BOMoNi and BOMoCo, respectively. The renewable hydrocarbons that were derived from BOMoNi and BOMoCo were mainly composed by olefins (35.3 and 33.4%), aromatics (31.4 and 28.9%), and paraffins (13.8 and 25.7%). The results revealed the catalysts' effectiveness in FFA decarbonylation and decarboxylation, as evidenced by significant changes in the van Krevelen space, with the lowest O/C ratio values for BOMoCo and BOMoNi (O/C = 0-0.10) in relation to the BOWCSO (O/C = 0.10-0.20), and by a decrease in the presence of oxygenated compounds in the catalytic bio-oils.