Search Results (347)

Monitoring trace nitrophenol pollutants in water has garnered considerable attention. A porous organic polymer-modified cellulose nanofiber membrane (COP-99@DCA) was fabricated via in situ growth of a porous organic polymer on an electrospun cellulose nanofiber membrane. The resulting brown COP-99@DCA composite possessed abundant functional groups, including C-F, C-O, and hydroxyl groups, and exhibited excellent thermal and chemical stability. Furthermore, when employed as a sorbent in dispersive solid-phase microextraction (d-SPME), COP-99@DCA efficiently enriched trace nitrophenols in water. Under optimal enrichment and desorption conditions, the enrichment efficiencies for five nitrophenol congeners ranged from 97.24% to 102.46%. Mechanistic investigations revealed that the efficient enrichment of trace nitrophenols by COP-99@DCA was primarily governed by hydrogen bonding, π-π stacking, and hydrophobic interactions. Coupled with solid-phase extraction (SPE) pre-treatment, high-performance liquid chromatography (HPLC) enabled the sensitive detection of trace nitrophenols. The established calibration curves exhibited favorable linearity, with low limits of quantitation (LOQs) ranging from 0.5 to 1 μg/L and low limits of detection (LODs) between 0.08 and 0.1 μg/L. Moreover, practical applications in real water samples confirmed the outstanding enrichment performance of COP-99@DCA. At spiked concentrations of 5 and 10 μg/L, the recovery rates were 85.35–113.55% and 92.17–110.46%, respectively. These results demonstrate the great potential of COP-99@DCA for practical water sample analysis. Collectively, these findings provide a novel strategy for the design of pre-treatment materials for the analysis of trace organic pollutants. Full article

Electronic waste (e-waste) is a growing solid waste stream with largely undisclosed and poorly characterized fluorinated constituents. We evaluated per- and polyfluoroalkyl substances (PFAS) leachability from four e-waste components (phone screens, phone plastics, capacitors, and Lithium-ion batteries) using a 30-day deionized water leaching test. PFAS were extracted by solid-phase extraction using weak anion exchange (WAX) cartridges and analyzed with a liquid chromatography triple-quadrupole mass spectrometer. In addition, the PFAS chemical profiles of e-waste components were characterized by non-targeted analysis. Leachable sums of detected PFAS (∑PFAS) were highest in phone screens (1739–1932 ng·kg⁻¹) and phone plastics (1575–2197 ng·kg⁻¹) and an order of magnitude lower in Lithium-ion batteries (148–158 ng·kg⁻¹) and capacitors (147–243 ng·kg⁻¹). Short-chain perfluoroalkyl acids (PFAAs) (e.g., PFBA, PFHxA) and legacy acids (e.g., PFOA, PFNA) were more prevalent in phone screens/plastics, whereas capacitors and batteries showed mixed sulfonate/carboxylate patterns (PFOS, PFHxS, and 6:2 FTS). Although capacitors and Lithium-ion batteries contained essential PFAS with high hazard potential at trace levels, phone screens and phone plastics pose a greater risk per mass due to higher ∑PFAS levels and larger volumes. Non-targeted analysis using Orbitrap Astral revealed CF₂/CF₂O homologous trends (confidence levels 2–3) with corroborating targeted findings. These findings highlight the need for PFAS-free alternatives, the disclosure of fluorinated additives, and stronger end-of-life management strategies to prevent PFAS releases from e-waste. Full article

This study investigates the technological and chemical causes of early zinc-coating degradation on cold-formed steel sections produced from DX51D+Z140 galvanized coils. Commercially manufactured products exhibiting early corrosion symptoms were used in this study. The entire processing route, which included strip preparation, cold rolling, hot-dip galvanizing, passivation, multi-roll forming, storage, and transportation to customers, was analyzed with respect to the residual surface chemistry and process-related deviations that affect the coating integrity. Thirty-three specimens were examined using electromagnetic measurements of coating thickness. Statistical analysis based on the Cochran’s and Fisher’s criteria confirmed that the increased variability in zinc coating thickness is associated with a higher susceptibility to localized corrosion. Surface and chemical analysis revealed chloride contamination on the outer surface, absence of detectable Cr(VI) residues indicative of insufficient passivation, iron oxide inclusions beneath the zinc coating originating from the strip preparation, traces of organic emulsion residues impairing wetting and adhesion, and micro-defects related to deformation during roll forming. Early zinc coating degradation was shown to result from the cumulative action of multiple technological (surface damage during rolling, variation in the coating thickness) and environmental (moisture during storage and transportation) parameters. On the basis of the obtained results, a methodology was proposed to prevent steel product corrosion in industrial conditions. Full article

The six platinum group elements (PGE) are among the rarest elements in the upper continental crust of the earth. Higher values of PGE have been detected in the upper mantle and in chondrite meteorites. The PGE are siderophile and chalcophile elements and are divided into the following: (1) the Ir subgroup (IPGE) = Os, Ir, and Ru and (2) the Pd subgroup (PPGE) = Rh, Pt, and Pd. The IPGE are more refractory and less chalcophile than the PPGE. High concentrations of PGE led, in rare cases, to the formation of mineral deposits. The PGE are carried in discrete phases, the platinum group minerals (PGM), and are included as trace elements into the structure of base metal sulphides (BM), such as pentlandite, chalcopyrite, pyrite, and pyrrhotite. Similarly to PGE, the PGM are also divided into two main groups, i.e., IPGM composed of Os, Ir, and Ru and PPGM containing Rh, Pt, and Pd. The PGM occur both in mafic and ultramafic rocks and are mainly hosted in stratiform reefs, sulphide-rich lenses, and placer deposits. Presently, there are only 169 valid PGM that represent about 2.7% of all 6176 minerals discovered so far. However, 496 PGM are listed among the valid species that have not yet been officially accepted, while a further 641 are considered as invalid or discredited species. The main reason for the incomplete characterization of PGM resides in their mode of occurrence, i.e., as grains in composite aggregates of a few microns in size, which makes it difficult to determine their crystallography. Among the PGM officially accepted by the IMA, only 13 (8%) were discovered before 1958, the year when the IMA was established. The highest number of PGM was discovered between 1970 and 1979, and 99 PGM have been accepted from 1980 until now. Of the 169 PGM accepted by the IMA, 44% are named in honour of a person, typically a scientist or geologist, and 31% are named after their discovery localities. The nomenclature of 25% of the PGM is based on their chemical composition and/or their physical properties. PGM have been discovered in 25 countries throughout the world, with 64 from Russia, 17 from Canada and South Africa (each), 15 from China, 12 from the USA, 8 from Brazil, 6 from Japan, 5 from Congo, 3 from Finland and Germany (each), 2 from the Dominican Republic, Greenland, Malaysia, and Papua New Guinea each, and only 1 from Argentine, Australia, Bulgaria, Colombia, Czech Republic, England, Ethiopia, Guyana, Mexico, Serbia, and Tanzania each. Most PGM phases contain Pd (82 phases, 48% of all accepted PGM), followed, in decreasing order of abundances, by those of Pt 35 phases (21%), Rh 23 phases (14%), Ir 18 phases (11%), Ru 7 phases (4%), and Os 4 phases (2%). The six PGE forming the PGM are bonded to other elements such as Fe, Ni, Cu, S, As, Te, Bi, Sb, Se, Sn, Hg, Ag, Zn, Si, Pb, Ge, In, Mo, and O. Thirty-two percent of the 169 valid PGM crystallize in the cubic system, 17% are orthorhombic, 16% hexagonal, 14% tetragonal, 11% trigonal, 3% monoclinic, and only 1% triclinic. Some PGM are members of a solid-solution series, which may be complete or contain a miscibility gap, providing information concerning the chemical and physical environment in which the mineral was formed. The refractory IPGM precipitate principally in primitive, high-temperature, mantle-hosted rocks such as podiform and layered chromitites. Being more chalcophile, PPGE are preferentially collected and concentrated in an immiscible sulphide liquid, and, under appropriate conditions, the PPGM can precipitate in a thermal range of about 900–300 °C in the presence of fluids and a progressive increase of oxygen fugacity (fO₂). Thus, a great number of Pt and Pd minerals have been described in Ni-Cu sulphide deposits. Two main genetic models have been proposed for the formation of PGM nuggets: (1) Detrital PGM represent magmatic grains that were mechanically liberated from their primary source by weathering and erosion with or without minor alteration processes, and (2) PGM reprecipitated in the supergene environment through a complex process that comprises solubility, the leaching of PGE from the primary PGM, and variation in Eh-pH and microbial activity. These two models do not exclude each other, and alluvial deposits may contain contributions from both processes. Full article

This study investigates 49 gold solidi issued between the 4th and 5th century AD to determine their chemical composition. The coins were first catalogued by recording mass, diameter, and thickness. All specimens underwent non-destructive µ-EDXRF analysis to identify main elements, followed by semi-quantitative fineness evaluation. To validate these results, six coins were randomly micro-sampled: material was dissolved in aqua regia and analysed by ICP-AES for gold quantification and ICP-MS for high precision trace element determination. The non-destructive analyses showed consistently high gold percentages, confirming authenticity and the extensive use of this noble metal during the studied period. Two distinct groups were identified based on the XRF Pt/Pd ratio, suggesting the use of gold from different sources. Comparison of μ-EDXRF and ICP-AES gold contents shows no statistically significant differences; however, this apparent agreement should be interpreted cautiously, as it mainly reflects the limited resolving power of ICP-AES at very high gold concentrations rather than definitive evidence for the absence of surface-related effects. Trace elements analysis detected low concentrations of Cu, Sn, and Pb suggesting the use of alluvial gold for minting. The presence and correlation of terrigenous elements (Al, Ca, Ti, Cr, Mn, Fe, Ni, Zn, Sr) indicate soil as the burial site. Full article

ISO 22002-100:2025 introduces stringent and more technically explicit prerequisite programme (PRP) requirements for allergen management, food fraud mitigation, and the control of chemical and packaging-related contaminants across the food, feed, and packaging supply chain. This review examines how advanced chromatographic methods provide the analytical basis required to meet these requirements and to support alignment with GFSI-recognized certification schemes. Recent applications of liquid and gas chromatography coupled with mass spectrometry for allergen quantification, authenticity assessment, and the determination of packaging migrants, auxiliary chemical residues, lubricants, and indoor pest-control pesticides are presented to demonstrate their relevance as verification tools. Across these PRP-related controls, chromatographic methods enable trace-level detection, structural specificity, and reproducible measurement performance, thereby shifting PRP compliance from a documentation-based activity to a process verified through measurable analytical evidence. The review highlights significant progress in method development and simultaneous multi-target analytical approaches while also identifying remaining challenges related to matrix-appropriate validation, harmonization, and analytical coverage for chemical contamination, which is now formally defined as a measurable PRP requirement under ISO 22002-100:2025. Overall, the findings demonstrate that chromatographic analysis has become essential to demonstrating PRP effectiveness under ISO 22002-100:2025, supporting the broader shift toward evidence-based, scientifically robust food safety assurance. Full article

The present study investigates the potential of poplar (Populus spp.) biomass from phytoremediation plantations as a feedstock for downdraft fixed bed gasification. The biomass was characterized in terms of moisture, ash content, elemental composition (C, H, N, O), and calorific values (HHV and LHV), confirming its suitability for thermochemical conversion. Gasification tests yielded a volumetric syngas production of 1.79 Nm³ kg⁻¹ biomass with an average composition of H₂ 14.58 vol%, CO 16.68 vol%, and CH₄ 4.74 vol%, demonstrating energy content appropriate for both thermal and chemical applications. Alkali and alkaline earth metals (AAEM), particularly Ca (273 mg kg⁻¹) and Mg (731 mg kg⁻¹), naturally present enhanced tar reforming and promoted reactive gas formation, whereas heavy metals such as Cd (0.27 mg kg⁻¹), Pb (0.02 mg kg⁻¹), and Bi (0.01 mg kg⁻¹) were detected only in trace amounts, posing minimal environmental risk. The results indicate that poplar pruning residues from phytoremediation sites can be a renewable and sustainable energy resource, transforming a waste stream into a process input. In this perspective, the integration of soil remediation with syngas production constitutes a tangible model of circular economy, based on the efficient use of resources through the synergy between environmental remediation and the valorization and sustainable management of marginal biomass—i.e., pruning residues—generating environmental, energetic, and economic benefits along the entire value chain. Full article

Marine natural products (MNPs) are a diverse group of bioactive compounds with varied chemical structures, but their biological origins are often misannotated due to complex host–microbe symbiosis. Propagated through public databases, such errors hinder biosynthetic studies and AI-driven drug discovery. Here, we develop a structure-based workflow of origin classification and misannotation correction for marine datasets. Using CMNPD and NPAtlas compounds, we integrate a two-step cleaning strategy that detects label inconsistencies and filters structural outliers with a microbial-pretrained graph neural network. The optimized model achieves a balanced accuracy of 85.56% and identifies 3996 compounds whose predicted microbial origins contradict their Animalia labels. These putative symbiotic metabolites cluster within known high-risk taxa, and interpretability analysis reveal biologically coherent structural patterns. This framework provides a scalable quality-control approach for natural product databases and supports more accurate biosynthetic gene cluster (BGC) tracing, host selection, and AI-driven marine natural product discovery. Full article

The use of agrochemicals remains indispensable for ensuring fruit production; however, their excessive or inefficient application poses significant environmental and health concerns. Rapid detection of spray deposition is crucial for assessing sprayer performance, improving precision application, and reducing drift and chemical waste. In this context, real-time monitoring technologies represent a promising tool to promote sustainable and efficient crop protection practices. This study refines previous experiences with an array of resistive sensors to quickly measure spray deposition. First, a multi-point calibration curve is introduced to improve the sensors’ accuracy. Furthermore, a multiplexed acquisition system (Sciospec ISX-5) is employed to enable time-resolved measurements of the whole sensor array. The method is validated by spectrophotometry and weight measurements. Wind tunnel trials with fluorescein (FLU) and fluorescein + potassium chloride (FLU + KCl) tracing solutions were conducted. The conductivity of the latter was higher than the former, without biasing the measurement. Both tracers showed good correlation between deposition and conductivity (R² = 0.997 for FLU and 0.995 for FLU + KCl), and the maximum deviation from the spectrophotometric estimates was <10%. Time-resolved measurement showed the build-up of deposition over time, potentially indicating the dimensional composition of the sprayed cloud. The improved workflow provides array-wide, sequential deposition measurements, enabling faster on-site acquisition and efficient analysis. The results demonstrate strong potential for scaling the method to field applications, supporting its further development into real-time deposition mapping tools that could guide precision spraying, optimize agrochemical use, and reduce environmental drift. Full article

Tropaeolum majus L. is a popular ornamental plant. All parts of T. majus plant (flowers, leaves, and seeds) are edible and are appreciated for their pungent taste, although their chemical composition varies. T. majus is known for its many health benefits. It is a source of trace elements and bioactive compounds that are easily absorbed by the human body. The flowers of T. majus contain flavonoids from the flavone and flavonol groups, as well as their glycosides, which exhibit antibacterial, antifungal and antiviral activity. They also inhibit the activity of certain enzymes. Among the flavonoids, the flowers and leaves of T. majus contain derivatives of kaempferol and quercetin. Flavonoids also include anthocyanins, which are responsible for the color of T. majus flowers. In red flowers, delphinidin predominates; in orange flowers, pelargonidin; and in yellow flowers, pelargonidin and delphinidin are present in similar amounts. In the flowers of T. majus, seven carotenoids have been identified: violaxanthin, antheraxanthin, lutein, zeaxanthin, α, β and γ-carotene. In the leaves, however, lutein, violaxanthin, β-carotene and neoxanthin were detected. In T. majus, the presence of two glucosinolates has been reported: glucotropaeolin and sinalbin. The flowers and leaves of T. majus also contain both macroelements (N, P, K, Ca, Mg, Na) and microelements (Fe, Mn, Cu, Zn, Mo), and essential oils which have anti-cancer, antibacterial, and antiviral properties. The quality and flowering of T. majus are enhanced by fungi of the Trichoderma genus, which is important both ecologically and in terms of increasing the yield of raw material extracted from the plant. T. aureoviride, T. hamatum, and T. harzianum stimulated the flowering of the T. majus ‘Spitfire’. The plants treated with T. harzianum after being planted in pots flowered the most abundantly. Trichoderma spp. caused the plants to grow more intensively, producing longer and more leafy shoots with a greater number of offshoots. Trichoderma spp. stimulated the uptake of macronutrients, except for P. In the case of Ca and Na, this phenomenon was only observed in plants treated with T. aureoviride and T. hamatum, and for Mg, only when T. hamatum was applied to sown seeds. As for the developed root systems, as far as the micronutrients are concerned, Trichoderma spp. stimulated the uptake of Zn and Mn. Additionally, there was a higher Fe content in the plants treated with T. harzianum on both dates and T. aureoviride after planting the plants in pots. Full article

Chemical oxygen demand (COD) serves as a critical indicator for assessing the extent of water pollution caused by organic matter. This study proposes an integrated COD detection methodology that combines laser absorption spectroscopy with laser-induced fluorescence spectroscopy, enabling accurate measurement of COD parameters across a wide concentration range. For high-concentration COD, conventional ultraviolet absorption spectrophotometry based on the Lambert–Beer law is employed. However, since laser absorption spectrophotometry exhibits substantial errors in detecting low-concentration COD, laser-induced fluorescence spectroscopy is adopted for the precise quantification of trace-level COD. By integrating these two laser-based approaches, a spectroscopic COD detection system has been developed that simultaneously records absorbance after the laser passes through the sample and quantifies fluorescence intensity perpendicular to the beam with an image sensor, thereby achieving comprehensive COD analysis. Laboratory validation using COD standard solutions demonstrated relative errors below 11% across the concentration range of 2–220 mg/L. Further application to natural water samples confirmed that the integrated laser absorption–fluorescence spectroscopy approach achieves wide-range COD measurement with high sensitivity, a compact configuration, and rapid response, demonstrating strong potential for real-time online water quality monitoring. Full article

Fe³⁺ and Fe²⁺ are widely present in red sandstone. However, systematic studies on the establishment of a quantitative relationship between the Fe³⁺/Fe²⁺ ratio and weathering degree of rock are scarce. In this study, on the basis of the coexistence characteristics of Fe²⁺ and Fe³⁺, as well as the ability of Fe²⁺ to form a stable orange–red complex with o-phenanthroline, an optimized o-phenanthroline spectrophotometric method for the multitarget determination of total iron, Fe²⁺, and Fe³⁺ was proposed and used to measure trace iron in the vertical profile of red sandstone. The effectiveness and reliability of the proposed method were validated via X-ray fluorescence spectroscopy (XRFS) and potassium dichromate titration. The results demonstrate that o-phenanthroline spectrophotometry offers advantages such as a low detection limit, high precision, and simple operation for the determination of trace iron in red sandstone. The vertical distribution pattern of the Fe²⁺/Fe³⁺ ratio is generally consistent with the macroscopic weathering intervals indicated by traditional chemical weathering indices. These findings suggest that the Fe²⁺/Fe³⁺ ratio has the potential to characterize vertical weathering zones and can serve as a simple auxiliary indicator for the rapid preliminary identification and classification of the relative weathering zones of red sandstone. Full article

Copper and nickel ions play pivotal, albeit distinct, roles as essential trace elements in living systems, and primarily serve as co-factors for a range of enzymes. However, as with all trace metal ions, excessive concentrations can exert adverse toxicological properties. Interestingly, the incorporation of these in cell culture media can establish novel chemical interactions, with their speciation status markedly influencing characteristics, including cell maturation, and cellular uptake mechanisms. Thus, the primary objective of this study was to investigate and determine the speciation status (i.e., complexation) of nickel(II) and copper(II) ions by biomolecules present in RPMI 1640 mammalian cell culture medium using virtually non-invasive high-resolution proton NMR analysis, an investigation of much relevance to now routine studies of their toxicological actions towards cultured cells. Samples of the above aqueous culture medium were ¹H NMR-titrated with increasing added concentrations of 71–670 µmol/L Ni(II)(aq.), and 0.71–6.7, 7.1–67 and 71–670 µmol/L Cu(II)(aq.), in duplicate or triplicate. ¹H NMR spectra were acquired on a JEOL ECZ-600 spectrometer at 298 K. Results demonstrated that addition of increasing concentrations of Ni(II) and Cu(II) ions to the culture medium led to the selective broadening of a series of biomolecule resonances, results demonstrating their complexation by these agents. The most important complexants for Ni(II) were histidine > glutamine > acetate ≈ methionine ≈ lysine ≈ threonine ≈ branched-chain amino acids (BCAAs) > asparagine ≈ aspartate > tyrosine ≈ tryptophan, whereas for Cu(II) they were found to be histidine > glutamine > phenylalanine ≈ tyrosine ≈ nearly all remaining aliphatic metabolites (particularly the wealth of amino acids detectable) > 4-hydroxyphenylacetate (trace culture medium contaminant), in these orders. However, Cu(II) had the ability to influence the linewidths of these signals at much lower added levels (≤7 µmol/L) than that of Ni(II), the broadening effects of the latter occurring at concentrations which were approximately 10-fold greater. Virtually all of these added metal ion-induced resonance modifications were, as expected, reversible on addition of equivalent or excess levels of the chelator EDTA. From this study, changes in the co-ordination sphere of metal ions in physiological environments can give rise to marked modifications in their physicochemical properties (e.g., redox potentials, electronic charges, the potential catalytic generation of reactive oxygen species (ROS), and cell membrane passages). Moreover, given that the above metabolites may also function as potent hydroxyl radical (^●OH) scavengers, these findings suggest that generation of this aggressively reactive oxidant directly from Cu(II) and Ni(II) ions in physiologically-relevant complexes may be scavenged in a ‘site-dependent’ manner. This study is of further relevance to trace metal ion research in general since it enhances our understanding of the nature of their interactions with culture medium biomolecules, and therefore provides valuable information regarding their overall chemical and biological activities, and toxicities. Full article

Baijiu, China’s traditional distilled spirit, is produced through solid-state fermentation and distillation of grains, resulting in a highly complex chemical and sensory profile. However, exogenous impurities introduced via raw materials, water, equipment, packaging, or the surrounding environment pose significant challenges to both safety and quality. These impurities, including heavy metals, plasticizers, pesticide residues, mycotoxins, environmental pollutants, and un-authorized food additives, are associated with neurotoxicity, carcinogenicity, endocrine disruption, and sensory defects. This narrative review synthesizes current knowledge on their sources, reported concentration ranges in Baijiu (generally at trace µg/kg–mg/kg levels), analytical detection methods with sub-mg/kg sensitivity, and control strategies for these substances. Regulatory frameworks, including China’s standards, are critically assessed, with emphasis on gaps such as the lack of explicit limits for certain classes of impurities. Case studies of contamination incidents are discussed to illustrate practical risks and monitoring gaps. Emerging trends, including low- and zero-alcohol Baijiu, are also considered in relation to changing impurity profiles and detection requirements. Recommendations include tightening regulatory limits, adopting portable and real-time detection technologies, and promoting the development of “pure Baijiu” that meets international safety and quality expectations. Future research priorities center on high-resolution mass spectrometry, advanced real-time monitoring, and eco-friendly analytical solutions, ensuring that Baijiu maintains both cultural heritage and global competitiveness. Full article

Cationic surfactants from the group of quaternary ammonium compounds (QACs) are widely used in disinfectants, cosmetics, and household and industrial products. Their strong antimicrobial activity and chemical stability make them valuable in applications but also highly persistent and toxic when released into aquatic environments. This problem has become increasingly relevant during and after the COVID-19 pandemic, when global use of QAC-based disinfectants increased drastically, resulting in their frequent detection in municipal, hospital, and industrial effluents. The concentrations of QACs reported in wastewater range from trace levels to several mg/L, often reaching inhibitory thresholds for biological treatment processes. Although surfactants are not listed in any current European directive, the revised Directive (EU) 2024/1440 classifies micropollutants as a priority group, imposing stricter environmental quality standards and mandatory monitoring requirements. Within this regulatory framework, QACs are recognized as compounds of emerging concern, and their effective removal from wastewater has become a critical challenge. This review summarizes the current knowledge on conventional treatment technologies (coagulation, adsorption, ion exchange, advanced oxidation, and biological processes) and membrane-based methods (ultrafiltration, nanofiltration, reverse osmosis, forward osmosis, and hybrid systems) for the removal of cationic surfactants from water and wastewater. Mechanisms of separation, performance, and operational limitations are discussed. Full article