Chemistry and Materials Science

Abstract: Among the micropollutants of medium-depth waters in isolated inhabited areas, the inorganic ones deserve special attention: nitrate anion (NO₃⁻) and phosphate anions (HxPO4^⁻(3⁻x)). The individual removal of these anions from water is widely studied, with different methods being found: chemical, ion exchange or biological. This paper presents a membrane method for the simultaneous removal of nitrate anion and phosphate anions from dilute synthetic aqueous solutions. The developed method is nanofiltration using composite membranes made of cellulose acetate (CA) and silver nanoparticles (Agnp). The composite membranes were made by phase inversion of the dimethylformamide (DMF) solution containing the two components (CA–Agnp) on a polypropylene (PP) capillary fiber using deionized waster as a coagulant. The DMF solution of CA containing Agnp was obtained by dissolving black-and-white cinematographic films (exposed and unexposed to light). CA–Agnp–PP composite membranes were tested for the simultaneous removal of nitrate anion and phosphate anions from aqueous solution by nanofiltration at pressures ranging from 5 to 25 bars. A removal of over 98% of phosphate anions and more than 95% of nitrate anion was achieved. Fluxes of 10 L·m^⁻2·h^⁻1 were obtained for the working pressure of 15 atm, depending on the pH, flow rate and concentration of the feed water (feed solution). Variable parameters studied were also the concentration of CA and Agnp.

Abstract: The rise in the presence and identification of biorefractory pollutants, also known as emerging contaminants (ECs) like microplastics, in the environment has been notable in recent times, attributed to factors such as population growth, changes in lifestyle, and rapid industrialization. A variety of pollutant substances are necessitated suitable remediation. Bioelectrochemical systems (BESs) represent sustainable technologies that can be utilized. In the current bibliometric investigation, the connection between bioelectrochemistry and pollutants in the environment is examined. Data obtained from the Web of Science database were utilized for the bibliometric analysis employing VOSviewer and R. According to the results, a highly integrated and rapidly maturing research landscape, characterized by a clear transition from fundamental technological development to large-scale environmental applications. The study serves as the essential bridge between the two primary pillars of the field: sustainable energy recovery and environmental remediation. The keyword co-occurrence networks illustrate a sophisticated synergy where the oxidative biodegradation of organic pollutants is directly coupled with electricity generation. A key discovery is the inherent synergy between the biodegradation of pollutants and the generation of electricity, which characterizes the contemporary ‘waste-to-energy’ model.

Abstract: The present study aimed to evaluate the stability of volatile organic compounds (VOCs) in exhaled breath samples under different storage conditions (refrigeration at -20 °C vs. room temperature) and analysis times (0 h, 3 h, 6 h, 12 h). Alveolar exhaled breath samples were collected from 30 volunteers in 500 mL Tedlar® bags, followed by analysis using headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC-MS). The results showed the putative identification of 73 metabolites, 41 of which were common to both conditions. Pre-analytical storage of the samples at -20 °C significantly altered (p < 0.05) the stability of 33 of the 41 common VOCs analyzed. Specifically, refrigeration improved stability by reducing the coefficient of variation (CV) in 23 of these metabolites compared to samples kept at room temperature. Highly stable metabolites with a CV < 15% were found. A 90% loss of the analytical signal was observed 12 hours after sample collection, in contrast to the stability maintained in refrigerated samples. These findings highlight the influence of pre-analytical conditions on the integrity of volatile profiles, establishing immediate refrigeration as a fundamental step for the study of potential biomarkers present in breath. These results provide key criteria for the standardization of breathomics protocols.

Abstract: Al Qurayyat salt is a traditional salt product that has been historically used in northern Saudi Arabia for food preservation, seasoning, and domestic uses. The city of Al Qurayyat is famous for its salt and is known as the city of salt in Saudi Arabia due to the abundance of salt deposits in areas such as Etra and Kaf. Despite its daily use by locals, there is no scientific information available regarding its chemical composition, heavy metals and safety. In this preliminary study, we aimed to analyze the physicochemical properties and metal contents of Al Qurayyat salt (ETR) and compare it to a commercially known salt (SAS). ETR chemical analysis showed a purity of 98.179%, moisture content of 0.68%, insoluble matter of 0.25%, and sulphate concentration of 7400 mg/kg. As expected, Iodine was not detected in the ETR sample, suggesting that the salt is non-iodized. Mineral analysis showed the presence of calcium (27 mg/kg), magnesium (32 mg/kg), potassium (10 mg/kg), copper (0.21 mg/kg), mercury (0.03 mg/kg), lead (0.13 mg/kg), and arsenic (0.01 mg/kg), while cadmium and iron were not detected or below the limit of detection. Heavy metal concentrations was below commonly accepted safety limits for edible salts. These findings provide the first reported physicochemical characterization of Al Qurayyat salt and establish baseline data for future investigations regarding its mineral composition, potential health uses, safety, nutritional significance, and potential industrial or culinary applications.

Abstract: The development of highly sensitive fluorescence sensing materials has attracted much attention in recent years. In this study, a new two-dimensional porous europium metal-organic frameworks (EuMOFs) have been obtained. Studies have shown that EuMOFs is a stable, fast response, and highly sensitive fluorescence sensor for isoprocarb and levofloxacin (Lvx), which are closely related to food safety and human health. The limits of detection (LOD) for isoprocarb and Lvx are as low as 1.0 and 0.5 nM, respectively, which were much lower than the national standards (GB 28260-2011 for isoprocarb is 2.583 μM). EuMOFs can also achieve strong anti-interference detection of isoprocarb in apple peel and rice extract solution, and Lvx in real urine, with excellent detection stability in 0.01~9.0 nM. The recovery rates for isoprocarb and Lvx in real samples are in 99.12%~101.25%.

Abstract: A cornerstone in transferring a classical liquid chromatography (LC) ultraviolet/visible (UV/Vis) method into greener and sustainable analytical method should consider the safety and toxicology of the used organic solvent in the method. Organic solvent portions used in the mobile phase may be replaced by a green solvent that is ideally bio-based and biodegradable to increase the greenness of the method. However, the implementation of a new solvent for high performance liquid chromatography (HPLC-UV/Vis) requires consideration of its environmental and health impact, cost-effectiveness, user-friendliness, and impact on the analytical performance and suitability of its chromatographic method. Existing greenness, blueness, and redness metrics expressing whiteness for evaluating the comprehensive sustainability of methods after solvent replacement overlook the chromatographic suitability of the selected solvent, this may potentially lead to suboptimal solvent replacement and an incomplete view of its capabilities. In this work, the authors present a Universal Suitability and Sustainability Index (USSI), a sixteen-parameter scoring system that quantifies four main factors for complete evaluation of a new solvent for implementation in HPLC. This index is beyond the white analytical chemistry principle. The four main factors are chromatographic suitability, greenness, blueness, and redness. Three of these factors, are based on available tools and metrics to evaluate the environmental and practicability impact on the health, and the analytical performance of the method. The fourth factor is added as an important criterion to judge the suitability of the solvent for HPLC analysis and to give an overview about its analytical applicability. The new index has been used to evaluate traditional liquid chromatographic as well as green solvents-based methods to give a universal overview that aids users to drive a rapid impression on the weakness and strength aspects and makes it easier to judge the selection of the solvent and the evaluation of the overall method sustainability.

Abstract: Trace water is one of the most critical matrix contaminants in ultra-high purity (UHP) process gases, like argon (Ar) and nitrogen (N₂), and many others. Even trace amounts can severely degrade the quality of many products reliant on these gases. Despite its importance to advanced technology sectors, notably semiconductor manufacturing, it has proven quite difficult to realize preparative or analytical trace water metrology over the full amount fraction range needed or in the broad spectrum of industrially relevant matrix gases. Within the EU-funded PROMETH2O project consortium, this challenge has been addressed through the development or significant improvement of traceable measurement methods and standards spanning 5 nmol mol⁻¹ to 5 µmol mol⁻¹, tailored for use in UHP process gas production, such as Ar, N2 and hydrogen (H2). The measurement ranges were extended and the uncertainties were improved, while being consistent with current best practice at primary humidity standards laboratories. These capabilities were validated in applications relevant to process instrumentation and the gas industry. A distributed metrological infrastructure at various European National Metrology Institutes and partner sites now provides SI-traceable trace water measurements in various UHP, strongly supporting and extending the calibration capabilities for the gas and semiconductor industries and the associated stakeholders.

Abstract: It is necessary to develop a sensitive and selective analytical method for detecting organophosphate insecticides, such as malathion, for environmental protection. Herein, we have designed an innovative sensing platform that incorporates silver nanoparticles (AgNPs) into molecularly imprinted polymers (MIPs), with AgNPs synthesized via in situ silver ion reduction during the precipitation polymerization of the MIP. Integrating AgNPs into MIP allows us to leverage both the selectivity and high sensitivity of molecular imprinting technology and the enhanced surface-enhanced Raman scattering (SERS) properties of AgNPs. The sensors demonstrate a linear detection range of 0.005-5 µg/ml and a limit of detection (LOD) of 0.005 µg/ml for malathion in water solution. The sensor is tested and evaluated in spiked drinking and tap water, obtaining recovery rates ranging from 93% to 100.5%. The AgNPs@MIP SERS sensor provides a rapid, selective, and sensitive approach for malathion detection, promising to develop an analytical tool for environmental and agricultural monitoring of organophosphate compounds.

Abstract: The development of efficient, visible light responsive and magnetically recoverable photocatalysts remains a critical challenge in wastewater remediation, particularly for the degradation of persistent azo dyes. In this study, a hierarchical nanocomposite consisting of NH₂-MIL-88B(Fe)-derived Fe₃O₄@porous carbon coupled with graphitic carbon nitride (g-C₃N₄) was successfully synthesized via a controlled pyrolysis and heterostructure assembling strategy. The NH₂-MIL-88B(Fe) precursor was synthesized solvothermally and subsequently carbonized at 500 °C under a nitrogen atmosphere to yield Fe₃O₄ nanoparticles embedded in a porous carbon matrix. The Fe₃O₄@porous carbon was then integrated with exfoliated g-C₃N₄ through ultrasonication assisted self-assembling to form a heterojunction nanocomposite. Structural, morphological, and optical characterizations confirmed the formation of a hierarchical porous architecture with enhanced visible light absorption and efficient charge separation. The photocatalytic performance was evaluated using methyl orange (MO) and Congo red (CR) dyes under visible light irradiation at λ > 420 nm, achieving degradation efficiencies of 98.6% and 96.8%, respectively, within 90 minutes at a catalyst dosage of 0.5 g L⁻¹. The composite exhibited excellent magnetic recoverability with a saturation magnetization of 32.4 emu g⁻¹, enabling facile separation using an external magnetic field. Mechanistic investigations revealed a Z scheme charge transfer pathway with dominant reactive species including •OH and •O₂⁻ radicals. The nanocomposite maintained over 92% of its photocatalytic efficiency after five cycles, demonstrating high stability and reusability. This work highlights a scalable strategy for designing multifunctional photocatalysts for environmental applications.

Abstract: Chirality is a cornerstone of biological systems and pharmaceutical activity, driving a crit-ical need for rapid and sensitive enantioselective analytical methods. Covalent organic frameworks (COFs) have emerged as versatile porous materials, and their chiral counter-parts, chiral COFs (CCOFs), uniquely combine high surface area, predesignable pores, and a confined chiral microenvironment, making them exceptional platforms for enantioselective fluorescence sensing. This review systematically summarizes recent advances in the construction and application of CCOFs for enantioselective fluorescence sensing. We first outline the primary synthetic strategies for CCOFs, including direct synthesis, post-synthetic modification, and chiral induction. Subsequently, based on the direction of fluorescence signal change upon analyte binding, we classify the sensing mechanisms in-to three categories: “turn-off” (quenching via static complexation or photoinduced electron transfer), “turn-on” (enhancement through rigidification or suppression of electron transfer), and ratiometric (self-calibrating dual-emission response). Representative examples for the detection of amino acids, amino alcohols, terpenes, and saccharides are highlighted for each mode. Special emphasis is placed on structure–property relationships, such as the synergistic roles of hydrogen bonding, π–π stacking, and framework confinement in amplifying enantioselectivity. Finally, we discuss current challenges and future perspectives, including the rational design of ratiometric sensors, integration into practical devices, and the convergence with machine learning to advance the field of smart chiral sensing.

Abstract: Candida albicans is an opportunistic fungal pathogen of clinical relevance, and plant-derived antifungal agents have attracted interest because of rising resistance to conventional drugs. This study evaluated the in vitro antifungal activity of Mespilodaphne quixos (Lam.) Rohwer essential oil (EO) against C. albicans, modelled its concentration-dependent response using a one-factor response surface methodology (RSM) design, and investigated the interactions of its constituents with selected fungal targets by molecular docking. Freshly collected leaves were subjected to steam distillation, and the EO was characterised by GC/MS. Antifungal activity was determined using the Kirby–Bauer disc diffusion method. A one-factor RSM design was applied to model inhibition halo diameter as a function of EO concentration. Besides, 22 identified compounds were docked against 14-α-demethylase, Δ(14)-sterol reductase, and exo-β-(1,3)-glucanase. The EO was mainly composed of (E)-cinnamaldehyde (47.2%), caryophyllene (10.8%), and α-humulene (5.37%). The EO reached an inhibitory capacity of 87.3% relative to ketoconazole. The quadratic model showed good predictive performance. Molecular docking revealed favourable affinities for several sesquiterpenes: α-copaene showed the best interaction profile against 14-α-demethylase and Δ(14)-sterol reductase, whereas α-guaiene and spathulenol performed best against exo-β-(1,3)-glucanase. These findings provide preliminary in vitro and in silico evidence supporting the antifungal activity of M. quixos EO.

Abstract: Carbon Capture and Storage (CCS) and Direct Air Capture (DAC) technologies must improve quickly due to the escalating climate problem, which is caused by annual CO₂ emissions reaching 37 billion metric tons. Because of their remarkable surface areas and customizable pore topologies, Metal–Organic Frameworks (MOFs) have become very intriguing sorbents; yet, exploring their large chemical design space is still computationally prohibitive. The growing significance of machine learning (ML) in advancing CO₂ capture research within MOFs is methodically examined in this review. We evaluate state-of-the-art models in four important areas using a structured evaluation protocol: process-level application, mechanistic interpretability, descriptor physical relevance, and predictive performance. Recent developments in Machine Learning Interatomic Potentials (MLPs) challenge traditional rigid-lattice assumptions by showing that framework flexibility greatly affects diffusivity and adsorption thermodynamics. While physics-informed descriptor engineering achieves R² values ranging from 0.81 to 0.97 depending on gas species and pressure regime, generative techniques, such as Deep Reinforcement Learning and transformer-based topologies, enable the inverse construction of high-affinity frameworks. Crucially, the field is moving away from isolated property prediction and toward multiscale, process-integrated optimization, where machine learning models combine material characteristics with industrial performance indicators like recovery and CO₂ purity in pressure swing adsorption systems. All of these advancements point to the need for physics-informed, comprehensible designs that can connect molecular-scale discovery with experimentally reliable, water-stable materials appropriate for commercial use.

Abstract: Copper is an indispensable trace element for maintaining metabolic homeostasis; however, the dysregulation and subsequent accumulation of Cu²⁺ are critically linked to neurodegenerative pathologies, including Alzheimer’s disease in humans. Consequently, the development of robust analytical tools for Cu²⁺ monitoring is of paramount importance. Here, we report a 2,2′-dipicolylamine porphyrin (DPAP) based fluorescent sensor designed for the precision detection of metal cations. Photophysical investigations reveal that DPAP operates via a rapid turn-off fluorescence mechanism, achieving high-performance sensing in the parts-per-million range. Notably, the probe demonstrates exceptional sensitivity with a detection limit of 30.3 nM for Cu²⁺ and 34.8 nM for Ni²⁺. Interference studies further confirm the superior selectivity of DPAP for Cu²⁺ over a broad spectrum of competing metal ions. These findings highlight DPAP as a simple, yet highly sensitive and selective probe for environmental monitoring and biomedical diagnostics involving copper ions.

Abstract: Diagnostic latency limits time-sensitive care and early detection, and exhaled breath provides a rapid, repeatable window into metabolic and inflammatory chemistry. We review real-time breath sampling and analytical technologies and evaluate their readiness for clinical adoption, with emphasis on molecular pathways reflected in the breath volatilome and in exhaled breath condensate. Real-time mass spectrometry enables kinetic VOC profiling and targeted quantification, while humidity-aware sensors and wearable condensate platforms extend monitoring beyond the laboratory. Pathway-anchored interpretation links breath readouts to ketone handling, isoprenoid metabolism, nitric oxide signaling, lipid peroxidation, uremic nitrogen handling, and microbiome-host co-metabolism, but performance remains vulnerable to confounding, drift, and non-representative comparators. Translation requires standardized breath fraction control, traceable features, robust quality systems, and governed device algorithm stacks so that breath outputs change decisions and outcomes.

Abstract: This study addresses the need for rapid, in situ detection of volatile organic compounds associated with oil contamination in aquatic environments. Membrane inlet mass spectrometry (MIMS) offers a direct and continuous monitoring approach without the need for chromatographic separation, making it suitable for real-time environmental analysis. In this work, a portable MIMS system was deployed at multiple pilot sites, including a fixed buoy platform, to evaluate its capability for detecting selected hydrocarbon target compounds under field conditions. Measurements were conducted over extended periods, and mass spectral data were continuously recorded and analyzed. Across all monitoring campaigns, no signals corresponding to the target analytes were observed above the established limits of detection. These findings demonstrate the robustness of the applied MIMS configuration for continuous environmental monitoring and confirm its suitability for detecting trace-level pollutants when present. The results also highlight the importance of field validation under realistic conditions, providing a basis for further optimization and broader application of MIMS in environmental surveillance.

Abstract: Arachidonate 5-lipoxygenase (ALOX5) is a key enzyme implicated in several inflammatory disorders, including asthma and allergic rhinitis. Despite its therapeutic importance, only one compound is currently approved as an ALOX5 inhibitor in the United States, highlighting the urgent need for new drug candidates. Progress in this area is often hindered by conventional bioassays, which can be labor-intensive, costly, and unsuitable for complex mixtures. To overcome these challenges, we developed a simple thin-layer chromatography (TLC) bioautographic assay for the rapid detection of ALOX5 inhibitors in natural extracts, a rich source of pharmacologically active compounds. The method exploits the oxidative coupling of 3-methyl-2-benzothiazolinone hydrazone (MBTH) with 3-(dimethylamino)benzoic acid (DMAB) during the ALOX5-catalyzed conversion of arachidonic acid, producing a colored indamine dye. Experimental parameters influencing chromogenic reaction were investigated and optimized to minimize reagent consumption while ensuring accuracy and sensitivity of the method. The assay was then applied to a panel of natural products and to crude mushroom extracts, enabling the rapid identification of several active compounds within complex extracts, including the dual COX2/ALOX5 inhibitor 3α-acetylpolyporenic acid A. Easy to implement, cost-efficient, and well suited for screening and bioguided fractionation, this TLC bioassay provides a powerful tool to accelerate the discovery of novel anti-inflammatory compounds.

Abstract: Hypochlorous acid (HClO) is widely used as a low-cost and effective disinfectant; however, its instability under heat and light necessitates simple and reliable monitoring methods. Herein, we report a morphology-evolving thin-film colorimetric sensor that enables intuitive visual detection of HClO through simultaneous color and pattern transitions. The sensor integrates two polymer films with distinct charge-state response behaviors, patterned into X-shaped and circular geometries on a single substrate. Upon exposure to HClO, chlorine-induced modification of amide and amine groups alters the surface charge states, thereby switching the adsorption preference for anionic and cationic dyes. This mechanism results in a pronounced transformation from a blue X-shaped motif to a red circular pattern, enabling direct visual discrimination of HClO concentrations. Quantitative analysis of RGB values and diffuse-reflectance UV–vis spectra confirmed semi-quantitative detection in the sub-millimolar to low millimolar range. The sensor further demonstrated practical applicability by tracking photodecomposition of a commercial disinfectant. This work demonstrates pattern-coupled colorimetric sensing as a straightforward, user-friendly approach for HClO monitoring.

Abstract: This study investigates the decomposition kinetics and microplastic residue formation of the polymer-coated controlled-release fertilizers (CRFs) LN40 and Eco-LN40 under simulated photodegradation conditions. Eco-LN40, containing TiO₂ as a photocatalyst, achieved complete decomposition (100 ± 2%) after 60 days of xenon-arc irradiation (p &lt;0.05), whereas LN40 achieved only 14%–31% decomposition. Analytical characterization using TED-GC/MS, FTIR, and Raman spectroscopy confirmed that polyethylene (PE) signals completely disappeared in Eco-LN40 but persisted in LN40, indicating that microplastics did not form and that there was total oxidation into CO₂ and H₂O. SEM–EDS revealed Ti enrichment and surface fragmentation consistent with photoinduced radical oxidation. This study provides qualitative and mechanistic evidence that TiO-catalyzed photodegradation can eliminate polymer residues, mitigate the risk of microplastic contamination in agricultural soils, and support carbon-neutral fertilizer technologies.

Abstract: A simple, rapid, and cost-effective method for the determination of BaP in edible oil was developed and validated. Nickel oxide deposited silica (SiO2@NiO) prepared by depositing nickel oxide onto silica using liquid phase deposition method was employed as solid-phase extraction (SPE) adsorbent for the extraction of benzo[a]pyrene (BaP) in edible oil followed by high performance liquid chromatography-diode array detector (HPLC-DAD) analysis. The edible oil was diluted with n-hexane and then directly loaded to SiO2@NiO for SPE. The n-hexane was also used to clean the fat-soluble interference in the edible oil, while BaP was selectively captured due to the electron donor-acceptor interaction with SiO2@NiO. The extraction conditions such as amount of sorbent, volume of washing solvent, type and volume of desorption solvent were optimized. The method demonstrated good linearity over the range of 6-1875 ng/g with the limit of detection of 1.3 ng/g, the spiked recoveries in the range of 97.4-105.1 %, and the relative standard deviation (RSD) less than 3.0 %. The method was applied for the analysis of BaP in 12 actual oil samples and the results showed that unrefined oil and high-temperature frying oil were at risk of BaP exceeding the acceptable level.

Abstract: Objectives: Using high-performance liquid chromatography (HPLC) we developed and validated an in vitro assay for the quantitative determination of beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) activity, supplementing limited current methodologies to assess the efficacy of BACE1 inhibitor compounds. A hexa-histidine tagged peptide substrate of BACE1 was used as the analyte for the determination of in vitro BACE1 activity; it was validated according to ICH guidelines. Methods: The HPLC analysis was performed on the Agilent 1290 Series Infinity II UHPLC System equipped with a Phenomenex Kinetex EVO C18 (100 × 3 mm) 5 µm column. The method was developed using a gradient program comprising of 10 % aqueous acetonitrile (0.02 M TFA) to 30% aqueous acetonitrile (0.02 M TFA) for 5 minutes at a flow rate of 0.6 ml/min. Results: The method showed linearity over the range of 14.92 to 72 µM with R^2=0.9997. The accuracy of the method in terms of mean recovery ranged between 96.62 to 98.38 %. The %RSD for intra- and inter-day precision were less than 5 %. Two commercial inhibitors, AZD3839 and OM99-2, were used to evaluate the performance of the method at their respective IC50, resulting in inhibition of 53.46 and 50.74 % respectively. The described method addresses the void for a practical and cheap alternative to quantitatively determine the activity of BACE1 compared to current commercially available detection assays. Conclusions: We have successfully developed a HPLC method to measure the inhibitory function of two commercial inhibitors of BACE1, indicating suitability of the method for the identification and characterisation of novel BACE1 inhibitors.