Search Results (123)

Cross-reactions between peroxy radicals (RO₂) derived from different volatile organic compound (VOC) precursors have been proposed as an important pathway during atmospheric oxidation. However, direct molecular evidence has been limited. In this study, α-pinene and fully deuterated toluene (d8-toluene) were oxidized separately and as a mixture in a potential aerosol mass (PAM) flow reactor, and the resulting secondary organic aerosol (SOA) was characterized by a high-resolution mass spectrometer (ESI FT-ICR-MS). A constrained chemical mass balance (CMB) model attributed 82.9% of the mixed-SOA signal to single-precursor sources (66.5% α-pinene, 16.4% d8-toluene), leaving a 17.1% signal-based residual fraction unexplained by linear mixing. Among 2450 residual molecular formulas exclusive to the mixed-SOA, 1858 were identified as cross-reaction candidates, with carbon, oxygen, and double bond equivalents (DBE) distributions consistent with RO₂-RO₂ cross-reactions between toluene- and α-pinene-derived fragments. We also identified representative monomer-dimer pairs, where one monomer corresponded to a known α-pinene oxidation product, while the other matched a primary oxidation product of d8-toluene oxidation based on the Master Chemical Mechanism (MCM), providing strong molecular-level evidence for RO₂-RO₂ cross-reactions. Our findings demonstrate that the mixed VOCs generate unique SOA products that extend beyond simple additive chemistry, with implications for SOA yield parameterizations and chemical transport models. Full article

Better understanding the controlling factors of shale oil quality including density and viscosity plays a key role in exploring these unconventional pay zones efficiently and profitably. The shale oil extracted from the middle Permian Lucaogou Formation (P₂l) of Santanghu Basin becomes denser and more viscous from the Tiaohu Sag to Malang Sag. It has been proven that oil quality is negatively correlated with saturated hydrocarbon content and positively correlated with aromatic/resin content. However, the underlying controls at the molecular levels are not yet clear. In order to reveal the fundamental controls, shale oil samples with varying density and viscosity were collected from these two sags, and molecular compositions of these samples were analyzed by using gas chromatography–mass spectrometry (GC–MS) for the saturated and aromatic hydrocarbons and electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT–ICR MS) for heteroatom hydrocarbons in resin fraction. Thereafter, correlation analysis was performed between oil density and viscosity and geochemical parameters associated with saturated, aromatic and NSO-containing compounds. The experimental results indicate that the oil thermal maturity levels play a major role, since both density and viscosity present significant negative correlations (correlation coefficient > 0.5) with the maturity parameters of n-alkanes, terpanes, steranes and triaromatic steranes. Organic facies also play a partial role as indicated by the significant positive correlations between density and viscosity and the parameters of tricyclic terpanes, dibenzothiophene/phenanthrene, and methylated phenanthrenes. In resin fraction, density presents better correlations with acid compounds, including O_x (x = 5–9), N₁O_x (x = 0–2) and N₂O₃ species, and viscosity shows better correlations with basic N-containing compounds (N₁O₁, N₁O₃, and N₂O₁ species) and S-containing compounds (N₁S₁ and O₁S₁ species). This indicates that the cross-linking by acid oxygen-containing compounds and the intramolecular and intermolecular forces induced by basic N-containing compounds and sulfur-containing compounds play an important role in directing the P₂l shale oil quality. Moreover, the ratios of specific species with low-to-high double bond equivalents (DBEs) and the homologues with low molecular weight to high molecular weight both present significant negative correlations with density and saturated and aromatic maturity parameters. This highlights the effects of bond cleavage, cyclization and aromatization reactions with elevated thermal maturity in enhancing oil quality in the targeted pay zones. Most P₂l shale oil sources were deposited under the reducing lacustrine setting, containing mainly Type I/II kerogens. Shale oils from Tiaohu Sag are more matured than those from Malang Sag, which is supposed to be responsible for the better oil quality in Tiaohu Sag. This study provides the supporting evidence for regulating shale oil quality in the Santanghu Basin at the molecular levels, and should be helpful in identifying the sweet spots of shale oil plays in this area. Full article

The growing demand for sustainable soil management strategies has intensified interest in hydrochar (HC), a waste-derived amendment produced via hydrothermal carbonization (HTC). This review synthesizes recent advances in HC production, characterization, and agri-environmental applications within a waste-to-resource framework. It covers studies conducted mainly over the last decade, encompassing a wide range of feedstocks, including agricultural residues, sewage sludge, animal manures, and food waste. HTC is typically performed at 130–280 °C under autogenous pressure (2–15 MPa), generating HCs with low intrinsic surface area (<50 m²g⁻¹) and oxygen-containing functional groups that govern nutrient dynamics and soil interactions. Reported application rates vary broadly between 10 and 60 t ha⁻¹, with most experiments conducted under greenhouse conditions. Positive effects on soil pH, cation exchange capacity, water retention, and phosphorus availability are frequently observed. However, plant responses vary according to the type of stimulation promoted by HC, as well as its processing conditions, application rates, and the soil characteristics in which it is applied. Advanced molecular-level analyses (e.g., FT-ICR-MS, GC-MS, and ¹³C-NMR) have provided mechanistic insights into carbon stability, nutrient release, and interaction with soil organic matter. Reusing HTC process water offers an additional pathway for nutrient recovery, although concerns about phytotoxic compounds remain. Despite promising short-term results, long-term field evaluations and standardized assessment protocols are still limited. This review integrates structural, functional and agri-environmental perspectives to identify critical knowledge gaps and guide the optimized and context specific use of hydrochar in sustainable agricultural systems. At the same time, it emphasizes its role in advancing carbon sequestration and in operationalizing resource-circular strategies, thereby underscoring its broader practical and strategic relevance. Full article

Desert oases and river systems are complex and dynamic ecosystems featuring unique hydrological patterns. The system significantly influences the production, degradation, and transformation of dissolved organic matter (DOM), thereby further regulating DOM in the desert oasis. However, the molecular composition and significance of DOM in rivers within desert oases are rarely studied. In this paper, the optical properties and spatial variation in molecular characteristics of surface water DOM in the Aksu River were investigated using three-dimensional fluorescence spectroscopy (3D-EEM) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The results indicated that the rivers possess distinct molecular compositional characteristics of DOM, with high spatial heterogeneity (variations in optical parameters and molecular compounds). Diversity in DOM is revealed at the molecular level primarily through S- and N-containing functional groups. Unlike large rivers (e.g., the Yangtze) dominated by terrestrial inputs or algal blooms, our study reveals that the DOM in the Aksu River (a desert-oasis river) is characterized by highly unsaturated and phenolic compounds and is primarily driven by intense photodegradation and evaporation rather than by microbial or terrestrial allochthonous inputs. This highlights a distinct photochemical signature unique to arid river systems. The findings will deepen the understanding of the DOM in desert-oasis river systems. Based on this research, seasonal variation in DOM in the Aksu River under different hydrological conditions can be further studied, thereby enriching the understanding of the carbon cycle in desert-oasis river systems. Full article

Asphaltenes are the most polar and refractory fraction of crude oil, and are typically isolated using petroleum-derived precipitants (e.g., n-hexane, n-heptane) and then dissolved in aromatic solvents such as toluene, which raises safety and sustainability concerns. Here we evaluate D-limonene, a renewable terpene, as a green, room-temperature precipitant for asphaltene fractionation and benchmark it against n-alkanes and the ASTM D-6560 workflow. Multi-technique characterization (ATR-FTIR/NIR, TGA, CHN, EDS, LDI(+) FT-ICR MS, and ¹H/¹³C NMR) shows that D-limonene yields a lower mass of precipitate yet a fraction with reduced thermal refractoriness (lowest TGA residue, broader/attenuated DTG peak). Molecular readouts indicate lower aromatic condensation/cross-linking in the precipitated subpopulation—narrower DBE envelopes by FT-ICR MS and lower aromatic carbon indices (Car_tot, Car-b, Car-j) by ¹³C NMR—consistent with a mechanism in which π–π/dispersion interactions retain highly condensed multi-ring aggregates in solution under cold, static conditions. These results establish D-limonene as a selective green precipitant for asphaltenes, offering immediate analytical benefits (cleaner, safer fractionation for molecular studies) and a sustainable basis for pretreatments of heavy fractions. Full article

Water contamination from diverse chemical pollutants has become a major environmental concern, demanding innovative and efficient remediation strategies. In this study, a Mg/Fe-layered double hydroxide (LDH) silica-magnetite hybrid composite was synthesized using a laser-cut microfluidic device to achieve controlled mixing and uniform particle formation. The obtained hybrid composite was further characterized by XRD, SEM, FT-IR, RAMAN, and DLS, confirming a structurally integrated LDH-silica-Fe₃O₄ hybrid, stabilized by ionic interactions, hydrogen bonds, and Si-O-Mg interactions. Moreover, biological assays confirmed that the developed material does not exhibit significant cytotoxicity and is potentially safe for environmental applications. Further, the adsorption performance was determined by treating surface water samples containing a mixture of pesticides with the composite material. After magnetic separation, the samples were analyzed by FT-ICR HR-MS, which enabled the detection and discrimination of ions with very close m/z values. The obtained results demonstrate a significant water decontamination capacity for multiple pesticides and facile water removal via magnetic separation, suggesting that these materials and the fast FT-ICR screening method are prospective, practical solutions for environmental protection of water bodies. Full article

Water represents the fundamental source of life for all human and animal populations; however, its consumption has become increasingly hazardous due to high levels of pollution. Modern agricultural practices rely heavily on pesticides, which significantly contribute to water contamination and imbalances in aquatic ecosystems. Moreover, another critical category of pollutants consists of pathogenic bacteria that proliferate in aquatic environments, mainly originating from hospital and urban wastewater because of human activity. Considering these major environmental and health challenges, the present study aims to develop an optimized method for water treatment by synthesizing magnetic silica-based aerogels using a microfluidic vortex chip and systematically varying synthesis parameters to enhance material performance. The physicochemical properties of the aerogels were characterized using XRD, FTIR, SEM, EDS, and BET. The pesticide adsorption capacity of the materials was evaluated using FT-ICR HR-MS analysis, which demonstrated the high efficiency of the aerogels in removing a complex mixture of pesticides. In parallel, antimicrobial efficacy was assessed against E. faecalis, E. coli, and P. aeruginosa isolated from surface water, hospital wastewater, and the influent of a well-known wastewater treatment plant in Bucharest, as well as against ATCC reference strains. Additionally, the study investigated the biocompatibility and biological responses of magnetic aerogels using MTT assays, nitric oxide production, lactate dehydrogenase release, intracellular ROS levels, and quantification of total protein, malondialdehyde, and reduced glutathione in HaCaT and HEK293 cell lines. The results confirm the efficiency and application potential of the developed materials and emphasize the importance of optimizing synthesis to achieve high-performance aerogels for effective decontamination of polluted waters. Full article

Dissolved organic matter (DOM) in salt lake brines comprises organic compounds dissolved in high-salinity aquatic systems. With complex composition and diverse sources, DOM significantly influences biogeochemical cycles, mineral formation, and resource development in salt lakes. However, few studies have investigated the characteristics and sources of DOM in salt lake brines. In this study, a DOM sample (YC-4) from brine of Shanxi Yuncheng Salt Lake was isolated and characterized using FT-ICR-MS, nuclear magnetic resonance spectroscopy, three-dimensional fluorescence spectroscopy, and parallel factor analysis. The results demonstrate that YC-4 DOM exhibits rich chemical diversity, primarily composed of lignin/CRAM-like compounds (54.26%), tannins (16.75%) and proteins (13.43%). The predominant carbon forms in YC-4 DOM were aliphatic C-O bonded compounds (33.74%), aliphatic compounds (24.31%), and carboxylic acid compounds (23.95%). YC-4 DOM consists of five fluorescent components: marine-like humic substances, two types of humic-like substances, fulvic-like substances, and one protein-like substance. The fluorescence signature, characterized by high fluorescence index (FI 1.99), low humification index (HIX 0.66), and high biological index (BIX 1.27), collectively indicates that the DOM in Yuncheng Salt Lake brine is predominantly autochthonous, weakly humified, and highly bioavailable. This study reveals the DOM feature within the “human–environment coupled system” of Yuncheng Salt Lake. The findings provide a scientific basis for the sustainable utilization of its brine DOM resources and further enrich the theoretical system of DOM biogeochemical cycle in high-salinity lake system. Full article

Brazil suffered the largest oil spill disaster in its history, beginning on August 2019, affecting the Northeast coast. This study proposes a chemical investigation of oils from the 2019 spill in Brazil, which had naturally undergone different weathering processes in terrestrial and aquatic environments after an extended period of exposure. Three samples were collected at different times and under distinct environmental conditions, coded as spilled oil (SO), oil recovered from the aquatic environment (SA), and oil collected from the terrestrial environment (ST), the latter two having spent more time naturally exposed to aquatic and terrestrial environments. The analyses were performed by gas chromatography–mass spectrometry (GC-MS) and electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). The results of the GC-MS analysis indicated that, although the samples share a common geochemical origin, the SA and ST samples showed a decrease in the intensity of n-alkane distribution compared to the SO sample, mainly attributed to evaporation and biodegradation processes. FT-ICR MS analysis identified dozens of classes of ESI(+) and ESI(–) compounds, most of them rich in sulfur and oxygen, with the highest intensities and quantities of molecular formulas in the SA and ST samples. Diagnostic ratios for heteroatom classes concluded that the SA and ST samples had undergone a higher level of weathering, mainly associated with photooxidation and biodegradation processes. Thus, the combined use of GC-MS and FT-ICR MS proved to be a robust approach for the detailed characterization of spilled oils, contributing to a clearer understanding of the extent and type of weathering in samples from the 2019 Brazilian spill. Full article

Dissolved organic matter (DOM) is a crucial carbon source for soil microorganisms and plays a vital role in nutrient cycling and carbon (C) sequestration in soils. However, the extent to which soil microbes mediate DOM transformation at the molecular level, and whether this is regulated by different organic fertilization, remains unclear. Here, we designed a field experiment to investigate the transformations of DOM under three types of organic fertilization (straw, biochar, and manure) using Fourier transform ion cyclotron resonance mass spectrometry and metagenomic analysis. Compared to the control, manure fertilization increased the molecular chemodiversity of DOM by 33.2%, with recalcitrant compounds (e.g., highly unsaturated phenolic compounds and lignins) increasing by 47.2%. In contrast, labile compounds (e.g., aliphatics) decreased by 73.5%. Compared to straw treatment, manure application significantly increased the average conversion rate of dissolved organic matter (DOM). This process was accompanied by a significant increase in the Shannon index of the soil microbial community (p < 0.05) and upregulation of ABC transporter-encoding genes (e.g., livK, livM). DOM composition directly governed transformation potential (p < 0.01), whereas functional genes enhanced transformation indirectly by modulating DOM composition. This study elucidates microbial-mediated DOM transformation mechanisms under varying organic fertilization practices, providing a scientific basis for optimizing soil organic matter management in paddy ecosystems. Full article

Cancer metabolomics has become a powerful way of understanding tumor biology, identifying biomarkers and metabolites, and helping precision oncology. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), among many other analytical platforms, has gained popularity over the past two and a half decades due to its unique ability of directly analyzing metabolites in tissue with spatial resolution. This review will study 2000–2025 MALDI-based strategies for cancer metabolite detection, spanning from early proof-of-concept protein profiling to the development of high-resolution MALDI-MS imaging (MALDI-MSI), which is capable of mapping thousands of metabolites at near single-cell resolution. Its applications include the differentiation of tumor versus normal tissue, discovery of stage and subtype specific biomarkers, mapping of metabolic heterogeneity, and the visualization of drug metabolism in situ. Breakthrough technological milestones, such as the advanced matrices, on-tissue derivatization, MALDI-2 post-ionization, and the integration with Orbitrap or Fourier-transform ion cyclotron resonance (FT-ICR) platforms, have significantly improved the overall sensitivity, metabolite coverage, and spatial fidelity. Clinically, MALDI-MS has shown its purpose in breast, prostate, colorectal, lung, and liver cancers by providing metabolic fingerprints that are linked to tumor microenvironments, hypoxia, and therapeutic response. However, challenges such as the inclusion of matrix interface with low-mass metabolites, limited quantitation, ion suppression, and the lack of standardized procedures do not yet allow for the transition from translation to routine diagnostics. Even with these hurdles, the future of MALDI-MS in oncology remains in a good position with major advancements in multimodal imaging, machine learning-based data integration, portable sampling devices, and clinical validation studies that are pushing the field towards precision treatment. Full article

In the context of promoting ecological alternatives to synthetic pesticides, this study investigates the antifungal activity of Trigonella foenum-graecum L. seed extract and its potential application in plant protection. The extract, obtained by maceration in 40% ethanol, was analysed using UV-Vis spectrophotometric methods to assess its phytochemical composition, including phenolic compounds, reducing sugars, and soluble proteins, as well as antioxidant activity in acellular system (ABTS, DPPH, TEAC, and CUPRAC) and CAT, SOD, peroxidase, and lipid peroxidation in planting material lysate. Additionally, the extract was qualitatively analysed using ATR-FT-IR and FT-ICR-MS methods. The antifungal activity was tested in vitro against three fungal strains, revealing significant inhibitory effects, especially on Fusarium graminearum and Monilinia laxa. Following the biogermination study on wheat seeds, it was highlighted that the extract obtained from fenugreek seeds manifested a strong inhibitory effect, especially at the highest concentration (1.50%) studied, probably due to the high content of phenols and presence of steroidal saponins (diosgenin and precursor diosgenin–protodiosgenin) and pyridine alkaloids (trigonelline). These findings suggest that Trigonella foenum-graecum seed extract possesses potent antifungal properties, making it a promising candidate for the development of biofungicides in sustainable agriculture. Full article

Phycocyanin, a blue pigment from Arthrospira platensis, is widely used as a natural colorant in food products, but its application is limited by its sensitivity to light and temperature during extraction and storage. This study explored the impact of UV light on phycocyanin extracted from A. platensis using a microwave-assisted method. Water proved to be the most effective solvent, yielding the highest phycocyanin concentration and stability. The optimal extraction conditions to avoid phycocyanin degradation were identified as 45 °C and 100 W of microwave power. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) analysis revealed increased chemical complexity at higher temperatures and identified biopterin–pentoside complexes, which enhanced phycocyanin stability during UV degradation. These findings provide new insights into the molecular mechanisms of interactions between phycocyanin and proteins, enhancing phycocyanin stability and functionality and thus providing food products with longer shelf lives by maintaining their nutritional and aesthetic qualities. Full article

Most lacustrine dissolved organic matter (DOM) still lacks comprehensive environmental sources and molecular characterization, especially in plateau lakes. Herein, macrophytes and algae from contrasting lakes of the Yunnan-Guizhou Plateau, together with Suwannee River fulvic acid (SRFA), were used to characterize the total identified DOM (Bulk-DOM) and low-molecular-weight DOM (LMW-DOM, <200 Da). To address this, we combined spectroscopy with Fourier transform ion cyclotron resonance (FT-ICR) and Orbitrap mass spectrometry (MS). Algae-derived DOM (ADOM) exhibited endogenous DOM characteristics, while macrophyte-derived DOM (MDOM) showed the characteristics of endogenous and terrigenous DOM. ADOM contained numerous heteroatoms, with high proportions of proteins, carbohydrates, and lipids. The chemical structures of ADOM were more aliphatic and degradable than that of MDOM. Conversely, MDOM and SRFA had higher degree of humification and aromaticity and showed greater resistance to microbial degradation. The capability of Orbitrap MS to characterize P-containing molecules was superior to FT-ICR MS. Moreover, significant differences were found between FT-ICR and Orbitrap MS in weighted average carbon atom number, weighted average mass-to-charge ratio, carbohydrates, and P-containing compounds. LMW-DOM accounted for approximately 10% of Bulk-DOM. Compared to Bulk-DOM, LMW-DOM was more active than Bulk-DOM because of the reduced state and more N-containing compounds. This study provides a valuable perspective to reveal the molecular characteristics and behaviors of ADOM and MDOM, which has crucial implications for carbon cycling in aquatic ecosystems. Full article

Swine wastewater (SW) has a high chemical oxygen demand (COD) content and is difficult to degrade; an effective strategy to address this issue is through biodegradation, which poses negligible secondary pollution risks and ensures cost-efficiency. The objectives of this study were to isolate an effective COD-degrading strain of SW, characterize (at the molecular level) its transformation of SW, and apply it to practical production. A strain of Corynebacterium xerosis H1 was isolated and had a 27.93% ± 0.68% (mean ± SD) degradation rate of COD in SW. This strain precipitated growth in liquids, which has the advantage of not needing to be immobilized, unlike other wastewater-degrading bacteria. Based on analysis by Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS), this bacterium removed nitrogen-containing compounds in SW, with proteins and lipids decreasing from 41 to 10% and lignins increasing from 51 to 82%. Furthermore, the enhancement of the sequencing batch reactor (SBR) with strain H1 improved COD removal in effluent, with reductions in the fluorescence intensity of aromatic protein I, aromatic protein II, humic-like acids, and fulvic acid regions. In addition, based on 16S rRNA gene sequencing analysis, SBR_H1 successfully colonized some H1 bacteria and had a higher abundance of functional microbiota than SBR_C. This study confirms that Corynebacterium xerosis H1, as a carrier-free efficient strain, can be directly applied to swine wastewater treatment, reducing carrier costs and the risk of secondary pollution. The discovery of this strain enriches the microbial resource pool for SW COD degradation and provides a new scheme with both economic and environmental friendliness for large-scale treatment. Full article