Fourier Transform Ion Cyclotron Resonance Research Articles

Linking Pattern Shifts of Dissolved Organic Nitrogen Fractional Removal with Microbial Species Richness in a Cascade Upflow Biofiltration Process

Nutrient pollution has become an important issue to solve in stormwater runoff due to the fast population growth and urbanization that impacts water quality and triggers harmful algal blooms. There is an acute need to link the dissolved organic nitrogen (DON) decomposition with the coupled nitrification and denitrification pathways to realize the pattern shifts in the nitrogen cycle. This paper presented a lab-scale cascade upflow biofiltration system for comparison of nitrate and phosphate removal from stormwater matrices through two specialty adsorbents at three influent conditions. The two specialty adsorbents are denoted as biochar iron and perlite integrated green environmental media (BIPGEM) and zero-valent iron and perlite-based green environmental media (ZIPGEM). An initial condition with stormwater runoff, a second condition with spiked nitrate, and a third condition with spiked nitrate and phosphate were used in this study. To differentiate nitrifier and denitrifier population dynamics associated with the decomposition of DON, integrative analysis of quantitative polymerase chain reaction (qPCR) and 21 tesla Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) were performed in association with nitrate removal efficiencies for both media with or without the presence of phosphate. While the qPCR may detect one gene for a single microbe or pathogen and realize the microbial population dynamics in the bioreactors, the 21 T FT-ICR MS can separate and assign elemental compositions to identify organic compounds of DON. Results indicated that ZIPGEM obtained a higher potential for nutrient removal than BIPGEM when the influent was spiked with nitrate and phosphate simultaneously. The sustainable, scalable, and adaptable upflow bioreactors operated in sequence (in a cascade mode) can be expanded flexibly on an as-needed basis to meet the local water quality standards showing process reliability, resilience, and sustainability simultaneously.

Formation of persistent free radicals from epigallocatechin Gallate in tea processing and their implications on DNA damage and cell cytotoxicity

Tea is widely consumed in both beverages and food. Epigallocatechin gallate (EGCG) is the most crucial active ingredient in tea. Currently, knowledges on transformation processes of EGCG during tea processing are lacking. Understanding the chemical reactions of EGCG and its products during tea processing is important for assessing the safety of tea-containing food. Here, we revealed the formation of persistent free radicals (PFRs) from EGCG under the influence of heating and light irradiation, which was substantiated with evidence. These PFRs exhibited stability for >30 min in simulated gastric fluid. Furthermore, we observed potential effects of these PFRs on DNA damage and cell cytotoxicity in vitro. By combining electron paramagnetic resonance spectrometer with Fourier transform ion cyclotron resonance mass spectrometry, we elucidated the pathways involved in free radical formation. These findings are expected to contribute to a comprehensive understanding of free radical chemistry in tea-containing food.

Effect of Nitrogen on the Structure and Composition of Primordial Organic Matter Analogs.

Organic molecules are ubiquitous in primitive solar system bodies such as comets and asteroids. These primordial organic compounds may have formed in the interstellar medium and in protoplanetary disks (PPDs) before being accreted and further transformed in the parent bodies of meteorites, icy moons, and dwarf planets. The present study describes the composition of primordial organics analogs produced in a laboratory simulator of the PPD (the Nebulotron experiment at the CRPG laboratory) with nitrogen contents varying from N/C < 0.01 to N/C = 0.63. We present the first Fourier transform ion cyclotron resonance mass spectrometry analysis of these analogs. Several thousands of molecules with masses between m/z 100 and 500 are characterized. The mass spectra show a Gaussian shape with maxima around m/z 250. Highly condensed polyaromatic hydrocarbons (PAH) are the most common compounds identified in the samples with lower nitrogen contents. As the amount of nitrogen increases, a dramatic increase of the chemical diversity is observed. Nitrogen-bearing compounds are also dominated by polyaromatic hydrocarbons (PANH) made of 5- and 6-membered rings containing up to four nitrogen atoms, including triazine and pyrazole rings. Such N-rich aromatic species are expected to decompose easily in the presence of water at higher temperatures. Pure carbon molecules are also observed for samples with relatively small fractions of nitrogen. MS peaks compatible with the presence of amino acids and nucleobases, or their isomers, are detected. When comparing these Nebulotron samples with the insoluble fraction of the Paris meteorite organic matter, we observe that the samples with intermediate N/C ratios bracketing that of the Paris insoluble organic matter (IOM) display relative proportions of the CH, CHO, CHN, and CHNO chemical families also bracketing those of the Paris IOM. Our results support that Nebulotron samples are relevant laboratory analogs of primitive chondritic organic matter.

Revealing Molecular Structures of Nitrogen-Containing Compounds in Dissolved Black Carbon Using Ultrahigh-Resolution Mass Spectrometry Combined with Thermodynamic Calculations.

Landscape wildfires generate a substantial amount of dissolved black carbon (DBC) annually, yet the molecular nitrogen (N) structures in DBC are poorly understood. Here, we systematically compared the chemodiversity of N-containing molecules among three different DBC samples from rice straw biochar pyrolyzed at 300, 400, and 500 °C, one leached dissolved organic carbon (LDOC) sample from composted rice straw, and one fire-affected soil dissolved organic matter (SDOMFire) sample using Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS). N-Containing molecules contributed 20.0%, 36.1%, and 43.7% of total compounds in Combined DBC (pooling together the three DBC), LDOC, and SDOMFire, respectively, and molecules with fewer N atoms had higher proportions (i.e., N1 > N2 > N3). The N-containing molecules in Combined DBC were dominated by polycyclic aromatic (62.2%) and aromatic (14.4%) components, while those in LDOC were dominated by lignin-like (50.4%) and aromatic (30.1%) components. The composition and structures of N-containing molecules in SDOMFire were more similar to those in DBC than in LDOC. As the temperature rose, the proportion of the nitrogenous polycyclic aromatic component in DBC significantly increased with concurrent enhanced oxidation and unsaturation of N. As indicated by density functional theory (DFT)-based thermodynamic calculations, the proportion of aliphatic amide N decreased from 23.2% to 7.9%, whereas that of nitroaromatic N increased from 10.0% to 39.5% as the temperature increased from 300 to 500 °C; alternatively, the proportion of aromatic N in the 5/6 membered ring remained relatively stable (∼31%) and that of aromatic amide N peaked at 400 °C (32.7%). Our work first provides a comprehensive and thorough description of molecular N structures of DBC, which helps to better understand and predict their fate and biogeochemical behavior.

Biochar data into structure: A methodology for generating large-scale atomistic representations

A well-defined methodology for constructing appropriate atomistic representations of biochar will aid in visualizing the structural features and elucidating biochar behavior with molecular dynamics (MD) simulations. Such knowledge will facilitate engineering biochars tailored to specific applications. To achieve this goal, we adapted modeling strategies applied in coal science by employing multi-cross-polarization 13C nuclear magnetic resonance, ultimate analysis, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy to identify functional groups. Helium density, surface area, and porosity were used to assess structural features. Biochar's aromatic cluster size distribution was proposed based on data from the benzene polycarboxylic acid method. The computational framework reduces bias by incorporating chemical information derived from density functional theory, reactive MD simulations, and advanced characterization data. The construction approach was successfully applied to cellulose biochars produced at four temperatures, obtaining independent representations with a relative error on the atomic contents of <10 % for oxygen and nitrogen and <5 % for carbon and hydrogen. The atomistic representations were validated using X-ray diffraction, electron spin resonance data, and laser desorption/ionization Fourier-transform ion cyclotron resonance-mass spectrometry. The code will assist others in overcoming structural creation barriers and enable the utilization of the generated structures for further simulations.

Molecular-level insights into dissolved organic matter and its variations of the full-scale processes in a typical petrochemical wastewater treatment plant

Petrochemical wastewater (PCWW) treatment poses challenges due to its unique and complex dissolved organic matter (DOM) composition, originating from various industrial processes. Despite the addition of advanced treatment units in PCWW treatment plants to meet discharge standards, the mechanisms of molecular-level sights into DOM reactivity of the upgraded full-scale processes including multiple biological treatments and advanced treatment remain unclear. Herein, we employ water quality indexes, spectra, molecular weight (MW) distribution, and Fourier transform ion cyclotron resonance mass spectrometry to systematically characterize DOM in a typical PCWW treatment plant including influent, micro-oxygen hydrolysis acidification (MOHA), anaerobic/oxic (AO), and micro-flocculation sand filtration–catalytic ozonation (MFSF–CO). Influent DOM is dominated by tryptophan-like and soluble microbial products with MW fractions 〈 1 kDa and 〉 100 kDa, and CHO with lignin and aliphatic/protein structures. MOHA effectively degrades macromolecular CHO (10.86 %) and CHON (5.24 %) compounds via deamination and nitrogen reduction, while AO removes CHOS compounds with MW < 10 kDa by desulfurization, revealing distinct DOM conversion mechanisms. MFSF–CO transforms unsaturated components to less aromatic and more saturated DOM through oxygen addition reactions and shows high CHOS and CHONS reactivity via desulfurization and deamination reactions, respectively. Moreover, the correlation among multiple parameters suggests UV254 combined with AImod as a simple monitoring indicator of DOM to access the chemical composition. The study provides molecular-level insights into DOM for the contribution to the improvement and optimization of the upgraded processes in PCWW.

Effects of reaction temperature and oxygen pressure on dissolved organic matter in hydrothermal reactions of municipal sludge: A comprehensive analysis

The impact of temperature and oxygen pressure on the basic performance of hydrothermal reactions and dissolved organic matter (DOM) was investigated. The results showed that total chemical oxygen demand and volatile suspended solids removal rate achieved a maximum of 72 % and 99 %, respectively, at 260 °C and 0.9 MPa oxygen pressure. Oxygen demonstrated a significant role in enhancing sludge particle dissolution. The interaction with temperature resulted in a complex trend for dissolved organic carbon (DOC) and specific ultraviolet absorbance at 254 nm. Acetic acid and formic acid were identified as the prominent volatile fatty acids, with formic acid prevalent at lower temperatures, while acetic acid accumulated with increasing temperature and oxygen pressure. Three-dimensional excitation emission matrix and Fourier transform ion cyclotron resonance mass spectrometry was also employed to analyse DOM as over half of the DOC remained unknown. Parallel factor analysis indicated that three components with 8 peaks in total might represent a universal feature for fluorescent DOM in hydrothermal reaction solution. The deciphered data from FTICR-MS indicated that lipids and lignins as well as CHOS and CHON molecules were the main components of DOM. Meanwhile, condensed hydrocarbons were formed at high temperatures in wet oxidation runs. Moreover, identification of C19H32O3S, C18H30O3S and C18H26N2O3 as crucial intermediates further enriched the understanding of hydrothermal reactions in municipal sludge.

Compositional differences of near-critical petroleum from closed pores to wellhead in Gulong shale oil play, Songliao Basin, NE China

The Gulong shale oil play located in northern Songliao Basin is a promising exploration target in China. Member 1 of Qingshankou Formation (Well H) with high thermal maturity was preferred to obtain pressure-retained cores, long-time exposed cores, and produced petroleum (crude oil and gas). The selected samples were subjected to sequential extraction, GC, GC-MS, thermal desorption–gas chromatography (TD-GC) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analysis. The compositional differences of in-situ fluids, residual bitumen trapped in open, confined, and closed pores, as well as wellstream, were systematically investigated. (1) In-situ fluid compositions, with a 30.8% proportion of nC1−5 in n-alkanes, were studied by TD-GC analysis on pressure-retained cores. Interestingly, limited amounts of C8- compounds were detected in long-time exposed bulk cores but were almost absent in exposed powder. Primally poor pore connectivity and partially adsorption or absorption of organic matter contribute to the retention of gaseous hydrocarbons. (2) Sequential extraction is a best method for obtaining compositions of fluid in pores with variable sizes. Aliphatic compounds of residual bitumen trapped in open pores are similar to those in confined pores, while polar compounds are more enriched in confined and closed pores. Originally connected pores in early oil window, has turned into confined or closed pores by compaction and cementation with increasing depth. (3) Wellstream compositions are significantly different from in-situ fluid compositions, especially in shale oil extraction. The proportion of gaseous hydrocarbons in the wellstream (76.2%) is considerably higher than that of in-situ fluids (34.1%). Comparison of aromatic hydrocarbons indicated that the wellstream is sourced from free fluids and partially adsorbed hydrocarbons in open pores. (4) Nitrogen and oxide compounds with a higher degree of condensation (higher DBE value) have poor movability, leading to extremely low content or even absence in crude oil. The compositional differences from in-situ fluids to the wellbore through the stimulated fractures are caused by selective adsorption of pore walls, confinement effect of nanopores and fluid phase changing. This study provides a window to the compositional differences of fluids released from different occurrence spaces and confirms compounds heterogeneity.

Different formation pathways of nitrogen-containing organic compounds in aerosols and fog water in northern China

Abstract. While aqueous-phase processing is known to contribute to the formation of nitrogen-containing organic compounds (NOCs), the specific pathways involved remain poorly understood. In this study, we aimed to characterize the NOCs present in both pre-fog aerosols and fog water collected at a suburban site in northern China. Fourier-transform ion cyclotron resonance mass spectrometry was utilized to analyze the molecular composition of NOCs in both negative and positive modes of electrospray ionization (ESI− and ESI+). In both pre-fog aerosols and fog water samples, NOCs constituted a significant portion, accounting for over 60 % of all assigned formulas in ESI− and more than 80 % in ESI+. By comparing the molecular composition of NOCs originating from biomass burning, coal combustion, and vehicle emissions, we identified that 72.3 % of NOCs in pre-fog aerosols were attributed to primary anthropogenic sources (pNOCs), while the remaining NOCs were categorized as secondary NOCs formed within the aerosols (saNOCs). Unique NOCs found in fog water were classified as secondary NOCs formed within the fog water (sfNOCs). Through a comprehensive “precursor–product pair” screening involving 39 reaction pathways, we observed that the nitration reaction, the amine pathway, and the intramolecular N-heterocycle pathway of NH3 addition reactions contributed 43.6 %, 22.1 %, and 11.6 % of saNOCs, respectively. In contrast, these pathways contributed 26.8 %, 28.4 %, and 29.7 % of sfNOCs, respectively. This disparity in formation pathways is likely influenced by the diverse precursors, the aqueous acidity, and the gas-phase species partitioning. Correspondingly, saNOCs were found to contain a higher abundance of carbohydrate-like and highly oxygenated compounds with two nitrogen atoms compared to pNOCs. Conversely, sfNOCs exhibited a higher content of lipid-like compounds with fewer oxygen atoms. These results underscore the distinct secondary processes contributing to the diversity of NOCs in aerosols and fog water, which may lead to their different climate effects.

Size-resolved molecular characterization of water-soluble organic matter in atmospheric particulate matter from northern China

Atmospheric particulate matter (PM) affects visibility, climate, biogeochemical cycles and human health. Water-soluble organic matter (WSOM) is an important component of PM. In this study, PM samples with size-resolved measurements at aerodynamic cut-point diameters (Dp) of 0.01–18 μm were collected in the rural area of Baoding and the urban area of Dalian, Northern China. Non-targeted analysis was adopted for the characterization of the molecule constitutes of WSOM in different sized particles using Fourier transform-ion cyclotron resonance mass spectrometry. Regardless of the location, the composition of WSOM in Aitken mode particles (aerodynamic diameter <0.05 μm) was similar. The WSOM in accumulation mode particles (0.05–2 μm) in Baoding was predominantly composed of CHO compounds (84.9%), which were mainly recognized as lignins and lipids species. However, S-containing compounds (64.2%), especially protein and carbohydrates species, accounted for most of the WSOM in the accumulation mode particles in Dalian. The CHO compounds (67.6%–79.7%) contributed the most to the WSOM in coarse mode particles (>2 μm) from both sites. Potential sources analysis indicated the WSOM in Baoding were mainly derived from biomass burning and oxidation reactions, while the WSOM in Dalian arose from coal combustion, oxidation reactions, and regional transport.

Fostering Adequate Data Reporting of Fourier Transform Ion Cyclotron Resonance Mass Spectrometry-Based Environmental Studies.

Fostering Adequate Data Reporting of Fourier Transform Ion Cyclotron Resonance Mass Spectrometry-Based Environmental Studies.

Molecular-level insight into the origin-dependent adsorption fractionation of dissolved organic matter on ferrihydrite in aquatic environment: Implications for carbon sink in eutrophic lakes

Molecular fractionation of dissolved organic matter (DOM) induced by adsorption on minerals plays a significant role in carbon biogeochemical cycling in water environment. However, the molecular-level adsorption of algae-derived DOM (ADOM) on minerals in eutrophic lakes remains poorly understood. Herein, we investigated the ferrihydrite-induced adsorptive fractionation of ADOM and humic DOM for comparison by using spectral analysis, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and solid characterization methods. We observed higher adsorption rate but lower adsorption capacity for ADOM than humic DOM. Spectroscopy and FT-ICR-MS indicated compounds with large molecular weight (>350 Da), high unsaturated and oxygen-rich were preferentially adsorbed for both ADOM and humic DOM. Specifically, the adsorption affinity order was aromatics > lignin-like > aliphatic compounds. Furthermore, tannin-like and condensed aromatics were predominantly adsorbed in humic DOM and protein-like formulas in ADOM. The solid characterization of ferrihydrite before and after adsorption further confirmed the dominant adsorption of aromatic and carboxylic-containing species in humic DOM and aliphatic materials in ADOM. Additionally, the contribution variation of oxygen atom to double bond in the molecular formula before and after adsorption identified absorbed oxygen-containing substances were predominantly aromatic carboxylic acids for humic DOM, but few aliphatic hydrocarbons substituted with ethers and alcohols for ADOM. These findings provided new insights into mineral-induced carbon sequestration, that is, increased release of ADOM in eutrophic lakes might influence the amount of organic carbon settled by ferrihydrite, and alter its quality from aromatic to aliphatic compounds transfer from water column to sediment through ferrihydrite adsorption.

Differential distribution of characteristic constituents in peel and pulp of Aurantii Fructus Immaturus (Citrus aurantium L.) using MALDI mass spectrometry imaging

Aurantii Fructus Immaturus (AFI) was structurally divided into two parts named “peel” and “pulp”. The exocarp and mesocarp of materials named “peel”. The endocarp separated into multiple compartments and the cystic hair attached to it named “pulp”. In order to explore the distribution and content of constituents in AFI, an efficient method to explore the distribution of constituents was developed based on matrix assisted laser desorption/ionization fourier transform ion cyclotron resonance mass spectrometry imaging (MALDI-FTICR-MSI). After simple processing, thirty-two constituents with distinct localization in the mass range of 101–1200 Da were identified by MALDI-FTICR-MSI. In addition, the identified four flavnoids (poncirin, sinensetin, 3,5,6,7,8,3′,4′-heptemthoxyflavone, and tangeritin) were analyzed for differences between using LC-MS. Quantitative analysis results supported the quantitative results from MALDI-FT-ICR-MSI. The results implied that different parts had different constituents in AFI, and demonstrated MALDI-MSI have high potential in the direct analysis of constituents.

Chemodiversity of dissolved organic matter exports from subtropical humid catchment driven by hydrological connectivity

The quantity and quality of dissolved organic matter (DOM) exported from source areas are closely related to hydrological linkage between source areas and streams, that is hydrological connectivity. However, understanding of how hydrological connectivity regulates the export of catchment DOM components remains inadequate. In this study, high-frequency monitoring of groundwater and runoff from subtropical humid catchment was conducted for 20 months, and hydrological connectivity was quantitatively characterized by considering both surface and subsurface hydrological processes. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was utilized to investigate the DOM molecular composition. Results showed that over half of the areas in the catchment could not persistently establish hydrological connectivity with the stream during the rainfall. The average proportion of lignin was the highest in DOM components, followed by tannin and proteins. Additionally, both modified aromaticity index and double bond equivalence reached maximums at peak discharge, reflecting terrestrial materials could increase DOM aromaticity and unsaturated degree. Partial least square-structural equation modeling revealed significantly direct effects of rainfall, antecedent conditions, and hydrological connectivity on dissolved organic carbon (DOC) export. Furthermore, nonlinear relationships were observed between hydrological connectivity and DOC, tannin, and condensed aromatics. Specifically, the instantaneous DOC flux increased dramatically when the hydrological connectivity strength exceeded 0.14; tannin and condensed aromatics exhibited a rapid increase with rising connectivity strength, but remained stable at connectivity strength above 0.25. However, hydrological connectivity showed no significant correlation with unstable components (such as lipids, protein, amino sugars, and carbohydrates). These results provide new insights into hydrological controls on the quantity and quality of DOM export and contribute to developing appropriate catchment management strategies for carbon storage.

Molecular-level carbon traits of fine roots: unveiling adaptation and decomposition under flooded conditions

Abstract. Fine roots are vital for plant development and carbon biogeochemical cycling in terrestrial ecosystems. Flooding is known to regulate the physiology and morphology in plant roots; however, its impact on molecular-level characteristics of carbon compounds (carbon traits) in fine roots remains largely unexplored, which limits our understanding of root adaptation and decomposition under changing environments. Here, we used a sequential extraction method, starting from nonpolar to polar solvents, in order to obtain dichloromethane- and methanol-extractable (FDcMe) fractions, base-hydrolyzable (FKOHhy) fractions, and CuO-oxidizable (FCuOox) fractions from fine roots of Dysoxylum binectariferum, which is naturally grown in soil and water. Subsequently, we characterized them using targeted gas chromatography–mass spectrometry and nontargeted Fourier transform ion cyclotron resonance mass spectrometry. Also, decomposition experiments were conducted on soil- and water-grown roots under aerobic and anoxic conditions. Results showed a consistent increase in the unsaturation degree and aromaticity of the analytes from FDcMe to FCuOox fractions. Both analyses were sufficiently sensitive to show that, compared to soil-grown roots, the water-grown roots developed more polyphenolics with a high unsaturation degree and aromaticity and had more nonstructural compositions. Furthermore, although flooding provided an anoxic condition that slowed down root decomposition, the adaptive strategy of developing more nonstructural labile components in water-grown roots accelerated root decomposition, thereby counteracting the effects of anoxia. This advances our understanding of biogeochemical processes in response to global environmental change.

Peatland Wildfires Enhance Nitrogen-Containing Organic Compounds in Marine Aerosols over the Western Pacific.

Peatland wildfires contribute significantly to the atmospheric release of light-absorbing organic carbon, often referred to as brown carbon. In this study, we examine the presence of nitrogen-containing organic compounds (NOCs) within marine aerosols across the Western Pacific Ocean, which are influenced by peatland fires from Southeast Asia. Employing ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) in electrospray ionization (ESI) positive mode, we discovered that NOCs are predominantly composed of reduced nitrogenous bases, including CHN+ and CHON+ groups. Notably, the count of NOC formulas experiences a marked increase within plumes from peatland wildfires compared to those found in typical marine air masses. These NOCs, often identified as N-heterocyclic alkaloids, serve as potential light-absorbing chromophores. Furthermore, many NOCs demonstrate pyrolytic stability, engage in a variety of substitution reactions, and display enhanced hydrophilic properties, attributed to chemical processes such as methoxylation, hydroxylation, methylation, and hydrogenation that occur during emission and subsequent atmospheric aging. During the daytime atmospheric transport, aging of aromatic N-heterocyclic compounds, particularly in aliphatic amines prone to oxidation and reactions with amine, was observed. The findings underscore the critical role of peatland wildfires in augmenting nitrogen-containing organics in marine aerosols, underscoring the need for in-depth research into their effects on marine ecosystems and regional climatic conditions.

Advanced Analytical Techniques for Characterizing Petroleum-Derived Contaminants in the Environment

The characterization of petroleum-derived contaminants in the environment is crucial for understanding their impact on ecosystems and human health. Traditional analytical techniques such as Gas Chromatography (GC), Mass Spectrometry (MS), and High-Performance Liquid Chromatography (HPLC) have been instrumental in identifying and quantifying these contaminants. However, the complexity and diversity of petroleum-derived compounds necessitate the development and application of advanced analytical techniques for more comprehensive analysis. This paper reviews the most cutting-edge methods currently employed in environmental analysis, including Comprehensive Two-Dimensional Gas Chromatography (GC×GC), Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS), Nuclear Magnetic Resonance (NMR) Spectroscopy, and Synchrotron Radiation-Based Techniques such as X-ray Absorption Spectroscopy (XAS) and X-ray Fluorescence (XRF), as well as Laser-Induced Breakdown Spectroscopy (LIBS). Each technique's principles, capabilities, and applications are discussed, highlighting their roles in detecting and characterizing hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), heavy metals, and volatile organic compounds (VOCs). Case studies demonstrate the practical applications of these advanced techniques in real-world scenarios, such as oil spill analysis and the identification of complex contaminant mixtures. The paper also addresses the advantages and limitations of these advanced techniques, considering factors like sensitivity, selectivity, complexity, and cost. Finally, future directions and emerging technologies, including nanotechnology, biosensors, and machine learning, are explored for their potential to enhance environmental monitoring and remediation efforts. This comprehensive review underscores the importance of continued innovation in analytical methods to effectively address the challenges posed by petroleum-derived contaminants in the environment.

Falsified and problematic methandienone products available online: active pharmaceutical ingredient identification by portable Raman spectrometers and quantification by ultra-high-performance liquid chromatography–Fourier transform mass spectrometry

This study aimed on the one hand to clarify the quality, authenticity, safety, and other issues related to products of the anabolic-androgenic steroid methandienone advertised on the Internet and personally imported to Japan and on the other hand to evaluate the use of two portable Raman spectrometers in identifying the active pharmaceutical ingredient (API). The study found that all n = 15 samples purchased from 14 websites were problematic regarding their package, labeling, and/or content. Specifically, one sample (6.7%) was confirmed falsified, twelve samples (80%) were found either to be falsified or unlicensed as pharmaceutical product, and two samples (13.3%) were received without information on the manufacturers’ physical address or country of origin, with one sample (6.7%) having no labeling or other accompanying information at all. Both Raman spectrometers were able to identify the API in all samples as confirmed and quantified by ultra-high-performance liquid chromatography–Fourier transform mass spectrometry. Twelve samples contained on average less than 90% of the declared API content. By contacting national regulatory authorities in 44 countries, methandienone products were found to be approved in 1 country and not approved in 21 countries. To prevent health hazards and abuse, measures against the acquisition of anabolic-androgenic steroids from unknown sources are required. Portable Raman spectrometers may be suitable for the non-destructive and quick identification of methandienone in tablets.Graphical

Molecular-level transformations of dissolved black carbon in UV-based advanced oxidation processes

Dissolved black carbon (DBC) released from biochar, is an essential group in the dissolved organic matter (DOM) pool and is widely distributed in aquatic environments. In various advanced oxidation processes (AOPs), DBC exhibits enhanced free radical scavenging compared to typical DOM, attributed to its smaller molecular weight and more compacted aromatic structure; however, the molecular-level transformations of DBC in different AOPs, such as UV/H2O2, UV/PDS, and UV/Chlorine, remain unclear. This study employed a DBC derived from wheat biochar for experimentation. Characterization involved ultraviolet-visible (UV–Vis) spectroscopy and fluorescence excitation-emission-matrix (EEM) spectroscopy, revealing the transformation of DBC through diminished SUVA254 values and reduced intensity of three-dimensional fluorescence peaks. Further insights into the transformation were gained through Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). After each UV-AOP treatment, a conspicuous augmentation in the oxygen content of DBC was observed. The detailed oxygenation processes were elucidated through mass difference analysis, based on 23 types of typical reactions. Results indicated that oxygenation reactions were most frequently detected in all three UV-AOP treatments. Specifically, the hydroxylation (+O) predominated in UV/H2O2, while the di-hydroxylation (+2O) prevailed in UV/PDS. UV/Chlorine treatments commonly exhibited tri-hydroxylation (+3O), with the identification of 1194 Cl-BPs of unknown structures. This study contributes to a comprehensive understanding of the molecular transformations of DBC induced by various free radicals in different UV-AOP processes, leading to a better understanding of the different fates of DBC in UV-AOP processes. In addition, the identification of DBC as a precursor of by-products will also contribute to the understanding of how to inhibit the generation of by-products.

Characterization of PP and PE Waste Pyrolysis Oils by Ultrahigh-Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Characterization of PP and PE Waste Pyrolysis Oils by Ultrahigh-Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry