Synthetic cathinones are among the most frequently encountered classes of new psychoactive substances, and many occur as structural isomers sharing identical molecular formulas and highly similar mass-spectral features. Among them, substituted cathinones with the molecular formula C12H17NO (MW 191 Da) present particular analytical challenges because of their similar chromatographic behavior and overlapping ionization patterns. This study evaluated a combined EI-GC-MS and ESI-LC-MS/MS workflow, incorporating derivatization with trifluoroacetic anhydride (TFAA) and acetic anhydride (AA), for the differentiation of ten MW 191 Da isomers. TFAA-derivatized GC-MS enabled preliminary classification of the isomers, although several EMC and MEC analogs remained only partially resolved. AA derivatization improved the separation of unresolved isomers under slower oven temperature conditions, demonstrating the value of alternative acylation for enhancing chromatographic discrimination. LC-MS/MS provided complementary confirmation for several analytes, but some isomers remained difficult to distinguish because of shared product ions and peak fusion in mixed-standard analysis. Overall, this study establishes a practical analytical workflow for distinguishing MW 191 Da substituted cathinone isomers and highlights both the strengths and limitations of combining derivatization-based GC-MS with LC-MS/MS confirmation in routine forensic or clinical laboratories.

In the interstellar medium (ISM), non-local thermodynamic equilibrium situations are common due to low density, and one needs to consider the effect of molecular collisions in order to interpret the observations. Among the species detected in the ISM, cyanopolyynes, with the general molecular formula HC2n+1N (n = 1, 2, …), are characterized by large dipole moments and small rotational constants and constitute an indispensable class of candidates for the sensitive tracers of local density and temperature. We present a study of the collisional (de-) excitation of HC5N by para-H2 (p-H2) in its ground rotational state, namely HC5N (j1) + H2 (j2 = 0) → HC5N (j1') + H2 (j2' = 0), where j1 (or j1') and j2 (or j2') denote the initial (or final) rotational quantum numbers of HC5N and H2, respectively. We performed the quantum scattering calculations at low collision energy using a new four-dimensional abinitio potential energy surface. In the regime where p-H2 remains in its rotational ground state, converged cross sections did not require including excited rotational states of p-H2 in the rotational basis. State-to-state cross sections were computed by means of the quantum-mechanical close-coupling (CC) method and the coupled states (CS) approximation, and rate coefficients for the first 61 levels of HC5N were computed for the first time up to 20 K with the CC approach and up to 50 K with the CS method. CC and CS results were found to agree well at temperatures up to 20 K. These data should allow a more accurate derivation of the HC5N abundance in molecular clouds.

Transformation products (TPs) have attracted increasing attention due to their widespread occurrence and potential adverse effects, and high-resolution mass spectrometry (HRMS) has been widely applied for their detection and characterization. However, the identification and structural elucidation of TPs from massive HRMS data sets remain challenging due to the limited availability of reference standards and the substantial manual effort required for data interpretation. In this study, we present a bottom-up workflow that integrates two open-source tools, Pyhrms and Transformapy, encompassing HRMS data deconvolution and prioritization, molecular formula assignment and verification, as well as parent-structure-guided structure elucidation, enabling systematic TP identification and structural characterization from HRMS data sets. This workflow was successfully applied to both controlled single-parent systems and complex environmental matrices such as wastewater treatment plants (WWTPs). Its broad applicability was further demonstrated using published data, in which 97.2% of 599 reported TPs could be annotated by assigning either tentative structures (n = 454), structure-inference steps (n = 119), or molecular formulas (n = 9). This approach provides a practical and extensible foundation for achieving more comprehensive and efficient TP elucidation, reducing manual interpretation efforts, and improving the assessment of transformation processes and environmental risks associated with emerging contaminants.

Umifenovir (UMI), an antiviral drug for influenza, has lately been employed in the treatment of COVID-19 infections. Degradation impurities of any drug are significant in pharmaceuticals because they impact a drug’s safety, efficacy, and stability, so it is important to study the degradation profile of UMI. Therefore, there is a need to develop a simple and fast method. UMI and its degradation impurities (DIs) were separated isocratically by UFLC (Ultra-Fast Liquid Chromatography) on a Shimadzu C18 column (250 mm × 4.6 mm, 5 μm) utilizing a mobile phase of acetonitrile (ACN): buffer (0.1% trimethylamine, pH 2.8 adjusted by using orthophosphoric acid) (60:40 % v/v). UMI was subjected to acid, alkaline, neutral, oxidative, thermal, and photolytic stress conditions as per ICH Q1A(R2) guidelines to assess stress-induced degradation behavior. Three DIs: DI1, DI2, and DI3 were formed. UMI degraded in acid, alkaline, neutral, and oxidation. For the structural elucidation of DIs, the UMI fragmentation and degradation pathways were estimated using Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS). Mass spectrometry is part of atomic spectroscopy; it is a technique for determining the elemental and isotopic composition of ions by measuring their mass-to-charge ratio. The molecular formula of fragment ions was determined using accurate values obtained from HRMS/Time-of-Flight (TOF), and this complete information helps identify the DIs. Later, the structures of DIs, along with the mechanisms of their origination, were proposed. The development of a UFLC method provides efficient separation of UMI and its DIs with a shorter total run time of 15 minutes, and the application of the hyphenated LC-HRMS technique for DI characterization is the novelty of the present work. The developed method can be utilized in pharmaceutical industries for the identification of DIs in API and tablet formulations, and it can be applied to analyze UMI in the presence of DIs in a shorter time.

Distinct molecular characteristics of humic-like substances (HULIS) in cloud water under land and marine influences.

Source-dependent composition and reactivity of effluent organic matter regulating disinfection byproduct formation and cytotoxicity.

Deciphering the environmental fate of halogenated organic compounds in cold seep sediments: Insights from non-targeted analysis and metagenomics across vertical redox gradients.

Macro- to molecular-scale insights into organic carbon redistribution during thermal hydrolysis-anaerobic digestion of waste activated sludge.

Integrating cheminformatics and high-resolution mass spectrometry to elucidate mechanisms of secondary organic aerosol formation from VOCs.

Pyrroloquinoline quinone alleviates age-related osteoarthritis via nuclear factor erythroid 2-related factor 2-mediated stress response and insulin-like growth factor 1 receptor upregulation.

Hybrid metal halides attract significant attention in materials science, chemistry, and photonics due to their attractive structural, electronic, and optical properties. However, zero-dimensional (0D) hybrid indium halides are still in their infancy. We report the first isomeric 0D indium halide single crystals showing green and delayed yellow emissions. Single-crystal X-ray structures reveal that these emissions originate from crystals with the molecular formula (C10H22N2)4In4Br20, consisting of organic ligands, InBr6 octahedra, and InBr4 tetrahedra. While both crystals carry eight corner-sharing and two face-sharing InBr6 octahedra, the four face-sharing InBr4 tetrahedra in the green-emitting isomer and two inner InBr4 tetrahedra in the yellow-emitting isomer mark the crystal isomerism, leading to distinct optical properties. The green-emitting crystals exhibit short excitonic lifetimes, whereas the radiative recombination in the yellow-emitting crystals is delayed by several hundred nanoseconds and redshifted, indicating a self-trapped exciton behaviour with a large Huang-Rhys factor and high activation energy. The structural and optical properties of the isomeric single crystals offer insights into the importance of developing 0D metal halides with multi-colour and delayed emission for sensors, LEDs, and displays.

Background: Medicinal plants remain an important source of biologically active compounds used in modern drug discovery. This study investigated the phytochemical constituents of Amaranthus spinosus leaf extract using Gas Chromatography–Mass Spectrometry (GC–MS) to identify potential bioactive compounds responsible for its pharmacological properties. Materials and Method: Resh leaves of Amaranthus spinosus were collected, shade-dried, pulverized, and extracted using aqueous extraction methods. The crude extract was subsequently analyzed by GC–MS, and the compounds were identified based on retention time, molecular weight, molecular formula, and comparison of mass spectra with the database of the National Institute of Standards and Technology (NIST). Results: The GC–MS analysis revealed the presence of twenty-four phytochemical compounds with retention times ranging from 1.422 to 22.795 minutes. The identified constituents belonged to several chemical classes, including esters, lactones, fatty acid derivatives, terpenoids, aromatic compounds, and nitrogen-containing heterocyclic compounds. Among the detected compounds, 4-Methoxy-6-methyl-6,7-dihydro-4H-furo[3,2-c]pyran showed the highest relative abundance (11.78%), followed by 3,4-Di-O-methyl-2-deoxy-D-ribono-1,5-lactone (10.00%), Cyclohexanemethyl propanoate (6.08%), 1-Propanone, 1-[5-ethyl-3-(5-nitro-2-furanyl)-1H-1,2,4-triazol-1-yl] (5.72%), and 2-Naphthalenemethanol derivatives (5.26%). Other notable compounds included Hexadecanoic acid methyl ester, 1,3,8-p-menthatriene, and several pyrrole, pyridine, and triazole derivatives. Many of the identified compounds have previously been reported to possess important biological activities such as antioxidant, antimicrobial, anti-inflammatory, antiviral, and anticancer properties. The presence of these diverse phytochemical constituents supports the traditional medicinal uses of Amaranthus spinosus and suggests that the plant may exert its therapeutic effects through synergistic interactions among multiple bioactive molecules. Conclusion: the GC–MS profiling of Amaranthus spinosus leaves showed that it is a rich source of pharmacologically relevance. The Plant has the potential in drug discovery, development and discovery. Further studies focusing on the isolation, purification, and biological evaluation of the identified compounds are recommended to fully elucidate their therapeutic potential.

The detection and sensing of amino acids through turn-on and ratiometric fluorescence signals are always challenging due to different shapes, sizes, acidities, basicities, and structural arrangement of amino acids. In general, amino acids are important biomarkers for identifying human health, providing a rapid, sensitive, and easy way to disease prevention and early diagnosis. Considering this, two highly fluorescent nitro-functionalized metal-organic frameworks (MOFs) have been designed using a mixed-ligands strategy, following a slow-diffusion technique. Both the compounds have a two-dimensional structure with the molecular formula {[Zn(4,4'-dps)(5-nip)](solvent)x}n (1) and {[Cd(4,4'-dps)(5-nip)(EtOH)]}n (2) (where 4,4'-dps = 4,4'-dipyridyl sulfide and 5-nip = 5-nitroisophthalate) and have been characterized thoroughly. The desolvated forms of 1 and 2 (1' and 2') are stable in different solvents and also within the wide pH range of 2-12. Interestingly, the fluorescence spectra of 1' and 2' showed photoinduced electron transfer (PET) driven turn-on fluorescence in the presence of tryptophan (Trp) with a low limit of detection. However, both the compounds involved in excited-state intermolecular proton transfer (ESPT) with aspartic acid (Asp), resulting in the selective ratiometric signal in fluorescence behavior. These observations allow the convenient method for the detection of aforesaid amino acids in water, through a diverse fluorescence mechanistic pathway.

Optical Chemical Structure Recognition (OCSR) plays a pivotal role in modern chemical informatics, enabling the automated conversion of chemical structure images from scientific literature, patents, and educational materials into machine-readable molecular representations. This capability is essential for large-scale chemical data mining, drug discovery pipelines, and Large Language Model (LLM) applications in related domains. However, existing OCSR systems face significant challenges in accurately recognizing stereochemical information due to the subtle visual cues that distinguish stereoisomers, such as wedge and dash bonds, ring conformations, and spatial arrangements. To address these challenges, we propose MolSight, a comprehensive learning framework for OCSR that employs a three-stage training paradigm. In the first stage, we conduct pre-training on large-scale but noisy datasets to endow the model with fundamental perception capabilities for chemical structure images. In the second stage, we perform multi-granularity fine-tuning using datasets with richer supervisory signals, systematically exploring how auxiliary tasks—specifically chemical bond classification and atom localization—contribute to molecular formula recognition. Finally, we employ reinforcement learning for post-training optimization and introduce a novel stereochemical structure dataset. Remarkably, we find that even with MolSight's relatively compact parameter size, the Group Relative Policy Optimization (GRPO) algorithm can further enhance the model's performance on stereomolecular. Through extensive experiments across diverse datasets, our results demonstrate that MolSight achieves state-of-the-art performance in (stereo)chemical optical structure recognition.

To date, the phytochemical composition of the aerial parts of Nanophyton iliense U.P. Pratov has not been comprehensively investigated. In the present study, qualitative metabolite profiling of the methanolic extract of the aerial parts was performed using liquid chromatography coupled with diode-array detection and quadrupole time-of-flight mass spectrometry (LC-DAD-QToF-MS) operating in both positive and negative electrospray ionization modes. A total of 81 metabolites were tentatively identified based on accurate mass measurements, MS/MS fragmentation patterns obtained in all-ion MS/MS mode, and comparison with previously reported literature data. The detected compounds included hydroxycinnamic acid amides, phenolic acids, flavonoids (including glycosides), amino acids, organic acids, sulfated derivatives, and nucleosides. Among them, the flavonoid narcissin (isorhamnetin-3-O-rutinoside) was isolated from the extract, and its structure was confirmed by 1H and 13C NMR spectroscopy supported by COSY, HSQC, and HMBC experiments. Additionally, a compound with the molecular formula C17H14O5 was detected; however, its structure could not be conclusively established based on the available spectroscopic data and is therefore reported as an unidentified metabolite. The present study provides the first systematic qualitative characterization of the metabolite profile of N. iliense and establishes a foundation for future quantitative and bioactivity-oriented investigations of this species.

<p><em>Zygophyllum cornutum</em> is recognized for its traditional medicinal use among certain populations in the northern Sahara of Algeria for different conditions, including hypertension and diabetes. The current study sought to ascertain the chemical composition and efficacy of <em>Zygophyllum cornutum</em> methanolic extract (ZcME) regarding cytotoxicity, antihemolytic properties, and antibacterial activity by agar diffusion experiment. Thirty-four bioactive phytochemical components were discovered in the methanolic extract of <em>Zygophyllum cornutum</em>. The identification of phytochemical substances relies on retention duration, molecular weight, and molecular formula. The study's findings first suggest that the methanolic extract of <em>Zygophyllum cornutum</em> is non-toxic at dose levels up to 20 mg/ml. ZcME had significant antimicrobial efficacy against Escherichia coli, exhibiting progressively larger inhibition zones at elevated concentrations (ranging from 8 mm at 5 mg/mL to 23 mm at 40 mg/mL), with all MIC/MBC values equal to 1, indicating the extract's bactericidal properties. At a concentration of 1.25 mg/mL, ZcME and ascorbic acid demonstrate equal antihemolytic activity (26% vs. 28%), indicating that, at this low dosage, ZcME may possess equivalent efficacy to ascorbic acid in safeguarding red blood cells from lysis.</p>

The moderate cytotoxic of isoeleutherol reported, a naphthalene-derived compound, from Eleutherine bulbosa bulbs collected in Simalungun, North Sumatra. The isolated compound, identified as (3S)-4-hydroxy-5-methoxy-3-methyl-3H-benzo[f][2] benzofuran-1-one, was characterised through FTIR, NMR and EIMS analyses, confirming its structural integrity and molecular formula C14H12O4. Methanolic extraction of the bulb yielded the highest isoeleutherol concentration (17.35 ± 1.72 ppm), indicating that the bulb serves as the primary storage tissue. The cytotoxic evaluation revealed moderate antiproliferative activity against HeLa, A549 and MCF-7 cancer cell lines, with IC50 values of 27.63 ± 2.52, 32.68 ± 1.60 and 50.13 ± 1.49 μM, respectively, showing the highest sensitivity in HeLa cells. The observed activity is attributed to the naphthoquinone-type framework. These findings provide scientific validation of E. bulbosa’s ethnomedicinal use and establish isoeleutherol as a potential lead compound for traditional herb medicine development.

Although Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) has been proven to be a powerful tool for the analysis of dissolved organic matter (DOM), obtaining more comprehensive molecular-level information about DOM remains extremely challenging due to its complexity. In this work, we found that ICR cell fills (ICRCF) have a significant impact on DOM detection using FTICR-MS. A multiple-ICRCF value of 10 is optimal, significantly enhancing peak intensities and the signal-to-noise ratio without inducing spectral artifacts. The multiple-ICRCF method identified more than 2400 additional molecular formulas compared to the single-ICRCF approach, particularly revealing more aromatic and less oxygenated compounds, as well as a substantial number of 13C1-isotopic peaks. The increased formula diversity improved the resolution of molecular profiles and enabled the construction of more complex and informative potential molecular transformation networks. Additionally, multiple ICRCF measurements effectively improved the sensitivity of FTICR-MS for DOM detection. These results demonstrated multiple ICRCF as a powerful supplementary technique for advancing molecular-level characterization of complex DOM, with implications for biogeochemical cycles.

The binding affinities of 24 ammonium salts were determined by isothermal titration calorimetry (ITC). The affinities were predicted with three empirical models that do not invoke the macrocycle explicitly. Once head groups common to all guests are removed, and the remaining fragments are transferred from aqueous solution to a virtual gas phase, the free energy of transfer from the gas phase to the CB[7] cavity is correlated with (a) the dispersive component of their interaction with a non-polar, non-polarizable hard sphere fluid, (b) their free energy of solvation in tetramethylglycoluril, that mimics the main building block of CB[7], and (c) a sum of individual guest atom free energy contributions via multiple linear regression. The latter method, which simply correlates binding affinities with the guest molecular formulae, is the most precise and accurate one, except for tight-fitting guests, with mean absolute errors as low as 0.16 kcal mol-1, thereby rivaling experimental error (0.06 kcal mol-1 on average). Accuracy exceeds density functional theory calculations that treat the host explicitly.

The unique phenomenon of high morphological diversity of quaternary phosphonium salts (QPSs) has been observed via electron and optical microscopy. The molecular structure of the QPSs, which differ by one methylene group, was shown to be reflected in the microstructure of the crystallized droplets. Here, we describe experimental datasets of scanning electron and optical microscopy images at different magnifications, illustrating the versatile microstructures of 19 homologous QPSs. The unique patterns that appear in the microscopy images of the QPS are related to the molecular structure. The described datasets of microscopy images are made openly available for scientific purpose and include hierarchical morphological patterns and fractal elements. Importantly, the datasets are suitable for both directions of machine learning exploration: recognizing molecular formulas from microscopy images and, conversely, predicting morphological patterns from molecular structures. This bidirectionality establishes a benchmark for bridging the molecule-morphology gap and advancing data-driven materials design.