Search Results (819)

Organophosphate esters (OPEs) are ubiquitous in the global water environment and may pose potential risks to aquatic ecosystems and human health. Herein, we present a simple and efficient method for accurate quantification of nineteen OPEs in water based on automated liquid–liquid extraction (LLE) with dichloromethane and hexane, followed by gas chromatography–tandem mass spectrometry (GC-MS/MS) with isotope dilution calibration. This method demonstrated a negligible matrix effect, satisfactory recoveries (70–120%), and low limits of detection (0.46–2.32 ng/L). A total of 3, 9, 10, and 11 OPEs were detected in Wahaha pure water, tap water, river water, and seawater, respectively, with total OPE (∑OPE) concentration ranges of 8.23–18.5 ng/L, 159–218 ng/L, 202–623 ng/L, and 111–175 ng/L, respectively. Among the detected OPEs, tris(2-chloroethyl) phosphate (TCEP) and tris(1-chloro-2-propyl) phosphate (TCIPP) were the predominant compounds in four test water matrices. The risk quotient (RQ) results revealed that OPEs exhibited a low risk to algae, crustaceans and fish in the river water of Zhoushan and seawater of Sanmen Bay. Overall, the proposed method is sensitive and reliable for routine OPE analysis in drinking and environmental waters. Full article

High-temperature temporary sealing operations require liquid plug materials that can be placed as low-viscosity precursors, converted into mechanically stable networks under reservoir temperature, and subsequently removed after service. Existing epoxy-based sealing systems generally provide high post-curing strength, but the coordination among pumpability, thermally triggered curing, and post-service degradability remains insufficiently addressed. In this work, an epoxidized soybean oil (ESO)-modified epoxy–anhydride liquid plug was designed to regulate these sequential stages within a single material system. The precursor formulation, rheological transition, curing kinetics, mechanical response, network structure, and degradation behavior were evaluated using viscosity monitoring, curing-time tests, DSC, compression testing, DMA, gel fraction and swelling measurements, FTIR, and high-temperature degradation experiments. The optimized precursor exhibited an initial viscosity of 65.4 ± 2.1 mPa·s, remaining below the pumpability threshold of 100 mPa·s before curing. Its curing time was adjustable within 1–10 h at 120–140 °C through temperature and initiator regulation. ESO incorporation produced a non-monotonic mechanical response, with the optimized network reaching a compressive strength of 112.5 ± 3.5 MPa and an elastic modulus of 142.50 ± 5.26 MPa. FTIR and thermal–mechanical analyses supported the formation of an ester-rich epoxy–anhydride network containing both rigid epoxy-derived segments and ESO-derived flexible chains. In the post-service stage, degradation was strongly temperature dependent, with the characteristic unsealing time decreasing from 84 h at 120 °C to 24 h at 130 °C and 18 h at 140 °C. The combined results define a coupled curing–degradation window in which pumpable placement, thermal network formation, load-bearing sealing, and controlled unsealing are temporally separated but structurally connected. Full article

Superhydrophobic materials offer promising prospects for utilization in energy, environmental, and related fields. However, their long-term stability in natural environments is constrained by factors such as mechanical wear and aging, which compromise their practical effectiveness and service life. While notable experimental results have been obtained worldwide, scalable application remains limited by the complexity of the requisite fabrication processes. In this study, a durable superhydrophobic coating was developed through a facile one-step process, utilizing a polyaspartic ester (PAE) matrix reinforced with a composite of self-synthesized fluorinated silica (F-SiO₂) and hexagonal boron nitride (h-BN) micro-/nano-structures. This strategy effectively enhanced filler dispersion within the resin matrix and promoted hydrophobicity, yielding a stable superhydrophobic surface. The resulting coating exhibits significant potential for scalable application. The optimized coating demonstrated a water contact angle of 161.2° and a roll-off angle of 7.6°, showing excellent repellency to water, corrosive liquids, and fluids across a wide pH range, along with remarkable self-cleaning performance. Benefiting from the synergistic enhancement of h-BN and F-SiO₂, the coating also exhibits superior mechanical durability, maintaining a contact angle of 144.4° after 1000 abrasion cycles. Furthermore, in low-temperature anti-icing tests, the coating significantly delayed ice formation on its surface. Notably, after 1000 h of UV aging tests, the F-SiO₂@BN/PAE coating retained its intact superhydrophobic structure, with the water contact angle only slightly decreasing from 159.6° to 152.8°, still within an excellent superhydrophobic state, demonstrating outstanding weather resistance. By integrating surface functionalization with mechanical reliability through a facile one-step fabrication process, this study provides significant insights for the large-scale application of hydrophobic materials in the energy and transportation sectors. Full article

This paper reviews emerging dielectric fluids for power transformers, including natural and synthetic esters, silicone oils, gas-to-liquid oils, and nanofluids, driven by environmental regulations, fire safety concerns, and the need for extended asset life. The review synthesizes technical data from standards and field experience, including a case study of an Eskom transformer energized in 2016 with natural ester fluid. Analysis confirms these fluids offer significant benefits in fire safety, biodegradability, and dielectric performance, with the case study demonstrating natural esters’ effectiveness in preserving solid insulation. However, trade-offs involving cost, material compatibility, and operational protocols require careful management. Full article

This study introduced freeze-withering to resolve the conflict in traditional Taiping Kuihong black tea processing, where rolling enhances flavor but damages the integrity of the leaf shape. Using sensory evaluation, high-performance liquid chromatography, and gas chromatography–mass spectrometry, the effects of three freezing treatments (−20 °C, −80 °C, and liquid nitrogen at −196 °C) were analyzed and compared with traditional withering (CK). The results demonstrated that low-temperature treatments better preserved the morphological integrity of ‘two leaves and one bud.’ Compared to the CK group, the −20 °C low-temperature treatment group had a significantly higher proportion of esters among the volatile compounds in Taiping Kuihong black tea. Key floral fragrance components were abundant, while grassy undertones were greatly decreased. Concurrently, this group had the highest levels of theaflavins and TF/TR ratios. The −80 °C treatment was highly effective in preserving thearubigins; however, it resulted in a less complex fragrance profile with a reduced theaflavin level. Liquid nitrogen treatment caused aberrant accumulation of theabrownins, poor aroma harmony, and the lowest theaflavin level. This study indicates that −20 °C freezing withering is the best method for harmonizing the appearance and internal quality of Taiping Kuihong, giving critical evidence for targeted processing of unique black teas. Full article

Caffeine and chlorogenic acid are among the most extensively investigated bioactive compounds in coffee, tea, and other plant-derived products due to their noteworthy physical, nutritional, and industrial relevance. Caffeine is primarily acknowledged for its central nervous system stimulant activity, whereas chlorogenic acid, a phenolic ester, contributes antioxidant, anti-inflammatory, and metabolic health benefits. This review was conducted according to the PRISMA guidelines in order to systematically compile and summarize the extraction and analytical conditions reported for caffeine and CGAs in different matrices and to provide a structured comparison among the reported studies. All studies focusing on the extraction and/or quantification of caffeine and chlorogenic acids in several matrices were considered eligible. Three independent electronic searches were performed using PubMed, Science.gov, and BASE to identify relevant articles. Extraction of data was conducted independently by four authors based on consistent selection and extraction criteria. One hundred and twenty-five studies were identified. The results were summarized in tables including several parameters. Conventional extraction techniques, including aqueous and organic solvent-based methods, have formed the foundation for separating caffeine and chlorogenic acids. However, rising interest in green and sustainable technologies has shifted attention towards advanced approaches such as ultrasound-assisted extraction and microwave-assisted extraction. These methods not only enhance extraction yields and reduce processing times but also align with environmental and safety concerns in the modern food and pharmaceutical industries. For quantification, high-performance liquid chromatography equipped with ultraviolet or mass spectrometric detection remains the benchmark, offering precision and reproducibility in different matrices. This review sheds light on recent advances and ongoing research in the extraction and quantification of caffeine and chlorogenic acid in different types of matrices. Continued innovation in green extraction technologies and robust quantification methods is essential for supporting scientific research applications. Full article

This work focuses on the production of biodiesel from Nannochloropsis sp. microalgae. The study compares the effectiveness of conventional methods, such as Soxhlet extraction and the Bligh and Dyer method with a non-conventional method that uses an ionic liquid as solvent for lipid extraction. The Bligh and Dyer method demonstrated superior efficiency with a lipid yield of 8.19% compared to Soxhlet extraction. Sample parameters were optimized in a maximum lipid yield of 18.29% at a sample volume of 91.9 mL, a duration of 7 min, and a power rate of 0.62 W. We further investigated the use of ionic liquids for lipid extraction from microalgae. We synthesized ionic liquids, and 1-(4 sulphonic acid) butyl-3-Methyl imidazolium hydrogen sulphate and 1-(4 sulphonic acid) butyl pyridinium hydrogen sulphate were characterized using FTIR, NMR and TGA. This method showed lipid extraction efficiency values of 10.7% and 0.402%. Subsequent transesterification of algal oil using 1-(4 sulphonic acid) butyl-3-Methyl imidazolium hydrogen sulphate yielded 19.82% biodiesel. FTIR analysis confirmed the presence of lipids and esters in the biodiesel, and the produced biodiesel met ASTM specifications, indicating its suitability for use as biofuel. Full article

This study investigated the effects of different cultivation environments on melon quality development and the underlying metabolic regulatory mechanisms. Using ‘Yangjiaocui’ and ‘Boyang 9’ melons, we systematically compared their physicochemical properties, nutritional components, volatile compounds, and metabolites under saline–alkali versus normal conditions, employing an integrated multi-omics analytical model. The results showed that saline–alkali cultivation significantly increased several nutritional components (e.g., soluble solids, vitamin C, flavonoids, and polyphenols) compared to normal conditions. Gas chromatography–ion mobility spectrometry (GC-IMS) detected 36 volatiles, predominantly esters and ketones, with 13 key markers such as isovaleric acid isovaleryl ester and ethyl butyrate, effectively discriminating cultivars and growth origins. Liquid chromatography–mass spectrometry (LC-MS) detected 702 metabolites, chiefly organic acids and lipids. KEGG pathway enrichment analysis revealed that flavonoid biosynthesis was the most significantly enriched pathway (enrichment factor ~1, extreme significance), with coordinated regulation of tyrosine and phenylalanine metabolism redirecting metabolic flux toward defensive secondary metabolites. In conclusion, our results suggest that saline–alkali cultivation may contribute to improved nutritional profiles, and multi-omics analysis effectively differentiates melon varieties and origins. This study provides a theoretical basis for understanding the quality, flavor, and metabolite profiles of melon under saline–alkali stress, employing a multi-omics approach. Full article

Food-deceptive orchids exhibit significant phenotypic variability in floral traits. However, the diversity of their floral low-volatility and volatile organic compounds (VOCs) remains poorly understood. This study investigated floral diversity in the orchid Anacamptis longicornu across six Sardinian populations to evaluate the influence of environmental factors and colour polymorphism on low-volatility and volatile profiles. Chemical profiles of flower extracts obtained through steam distillation followed by liquid–liquid extraction were characterized using GC/MS analysis. A total of 79 compounds were identified, primarily saturated and unsaturated hydrocarbons, alcohols, ketones, aldehydes, esters, mono- and sesquiterpenes. Dominant compounds across both violet and white morphs included nonadecane, eicosane, octadecane, henicosane, and docosane. Significant chemical variability was detected among populations and between colour morphs, indicating that colour polymorphism substantially shapes floral profiles. Environmental heterogeneity also emerged as a critical driver, with populations exposed to extreme conditions exhibiting increased chemical diversity. Furthermore, greater geographical distance among populations correlated with higher dissimilarity in floral profiles. This study provides the first comprehensive characterization of floral diversity in A. longicornu, confirming that phenotypic variability extends to chemical traits in food-deceptive orchids. Our results highlight that the diversification in food-deceptive orchids arises from a combination of biotic and abiotic drivers. Full article

This study presents an innovative approach for the selective extraction of Co(II) and its separation from Ni(II) using ethyl ester glycine–betaine derivatives, specifically tri(n-pentyl)[2-ethoxy-2-oxoethyl]ammonium dicyanamide, as extractants in combination with continuous-mode liquid–liquid contact. Semi-pilot-scale implementation requires non-equilibrium conditions, characterized by short contact times between effluent and extractant phases. To address this, we propose dissolving analog of glycine–betaine ionic liquid (AGB-IL) in low-viscosity MIBK solvents to enhance mass transfer while reducing dependence on fossil-based solvents. Liquid–liquid extraction and continuous-flow stripping experiments were designed based on prior batch results and conducted in a saline environment, employing a chaotropic electrolyte for extraction and a kosmotropic electrolyte for stripping. Both open and closed systems were tested to compare extractive performance with batch conditions and with scenarios representative of industrial operations. Results indicate that continuous-flow systems achieve performance comparable to batch systems in terms of extraction efficiency, Co/Ni separation coefficients, and recyclability. These findings provide proof of concept for the development of semi-pilot and pilot-scale processes for efficient cobalt recovery. Full article

Nanostructured lipid carriers (NLCs) are colloidal delivery systems developed to address the low stability and limited bioavailability of sensitive active compounds. In this study, anthocyanin-rich barberry extract-loaded NLCs were prepared by a water-in-oil-in-water double emulsion method, using beeswax as the solid lipid and coriander essential oil as the liquid lipid. A combined D-optimal mixture design was employed to evaluate the effect of surfactant ratios (Tween 80/Tween 20 and polyglycerol ester (PGE)/polyglycerol polyricinoleate (PGPR)) on particle size, polydispersity index (PDI), zeta potential, and encapsulation efficiency. The optimized formulation suggested by Design-Expert^® software was obtained at 90/10 Tween 80/Tween 20 and 90/10 PGE/PGPR ratios and showed a particle size of 94.25 nm, PDI of 0.18, zeta potential of −23.4 mV, and encapsulation efficiency of 74%. The experimental values were in close agreement with the predicted responses. TEM observations indicated spherical morphology at the nanoscale, while FTIR, DSC, and XRD analyses confirmed successful incorporation of barberry extract into the lipid matrix and a less ordered crystalline structure. During one month of storage, the optimized NLC was more stable at 4 °C compared with 25 °C and showed higher antioxidant activity than the free extract. It also exhibited a higher inhibitory effect against S. aureus and E. coli than the free form in MIC and MBC assays. Overall, the developed NLCs could serve as an effective carrier system to improve the stability of anthocyanin-rich barberry extract and extend its application in food formulations. Full article

Nail cosmetics, such as nail polish or nail conditioners, are considered as safe; however, their use may be accompanied with risks, e.g., related to contact of allergens with the periungual skin or to the transfer of a small amount of cosmetic to other areas of the skin. Therefore, the identification of potentially dangerous ingredients of nail cosmetics is of importance. In this work non-volatile organic compounds present in nail conditioners were analyzed by high-pressure liquid chromatography-mass spectrometry. Unexpectedly, in two samples the esters of phthalic acid with neopentyl glycol and mixed esters of phthalic acid with neopentyl glycol/propylene glycol were detected. Their structures were deduced on the basis of characteristic fragmentation pathways. It is reasonable to suppose that these compounds were formed by the reaction between the ingredients of the analyzed samples. The second group of the detected non-volatile organic compounds were quaternary ammonium salts, which are quite common in cosmetic products. These compounds were most probably transferred to the conditioners from the material from the inside of barrels in which the nail conditioners were stored. Although the presence of detected non-volatile organic compounds in nail conditioners is not particularly dangerous to human health, it is worth knowing that they can occur in the analyzed type of cosmetic products. Full article

Toxicological testing for drugs of abuse (DOAs) is an essential tool for healthcare practitioners and law enforcement agencies. Oral fluid (OF) is an alternative biological fluid for detecting recent DOA intake and is widely employed in forensic investigations. In the current study, a relatively novel and “green” fabric phase sorptive extraction (FPSE) procedure for sample preparation was coupled to liquid chromatography–tandem mass spectrometry (LC–MS/MS) to provide simplicity, cost-effectiveness, rapidity, low solvent consumption, and high analytical performance for the quantitative determination of ten commonly encountered DOAs and metabolites: amphetamine, benzoylecgonine, cocaine, codeine, ecgonine methyl ester, methadone, methamphetamine, 3,4-methylenedioxyamphetamine, 6-monoacetylmorphine, and morphine. The FPSE procedure was optimized by testing different filters, pH, extraction time, and solvents. The validated method demonstrated excellent linearity for all analytes, selectivity, acceptable precision, and high sensitivity (ranges for limits of detection (LODs) and quantification (LOQs) were 0.01–2 ng/mL and 0.03–6 ng/mL, respectively). Autosampler and short-term freeze stability exceeded 95% and 90% for all analytes, respectively. Overall, the combination of FPSE with LC–MS/MS provided a sensitive, selective, and environmentally friendly innovative analytical approach for the determination of DOA in OF and is suitable for both screening and confirmatory forensic and clinical applications. Full article

Pesticide manufacturing industry wastewater is a complex mixture of potentially harmful components. If not properly treated, discharged effluents may pose serious risks to environment and organisms. In this study, influent and effluent wastewater samples from a pesticide factory were comprehensively non-screened by liquid chromatography high-resolution mass spectrometry, coupled with zebrafish embryo toxicity testing to assess whole effluent toxicity. A total of eight chemical groups were identified, including pesticides, antibiotics, nitrogen compounds, ketones, esters, amines and derivatives, other drugs, and other organic compounds. While wastewater treatment processes reduced most of the analyzed groups of compounds, compounds (e.g., 2-aminophenol, N-Nitrosodipropylamine, and carbamazepine) increased during the treatments. The influent samples were more toxic to zebrafish than the effluent samples in terms of lethality, teratogenic effects, developmental impacts, locomotor behavior, and neurotoxicity. The results showed that locomotor behavior was the most sensitive phenotypic toxicity endpoint, with significantly higher sensitivity than traditional acute lethal or teratogenic endpoints. Through a multi-dimensional assessment approach combining chemical screening, literature-based, risk ranking, and targeted quantification, we identified three predominant pesticide residues in the wastewater samples (both influents and effluents): hexaconazole, fenobucarb and isoprocarb. All three compounds exhibited additive or synergistic toxicity in zebrafish embryos. Exposure to ≥0.08% influent or ≥2% effluent increased inflammation (interleukin-1 beta, IL-1β), oxidative stress (copper/zinc superoxide dismutase, Cu/Zn-Sod), apoptosis (tumor protein p53, p53), and significantly impaired neurodevelopment in zebrafish larvae by altering the expression of sonic hedgehog a (shha), synapsin IIa (syn2a), and glial fibrillary acidic protein (gfap). This study suggests the necessity of incorporating non-apical endpoint (locomotor behavior) into whole effluent toxicity test, as this approach is essential for reducing the environmental risks posed by pesticide factory wastewater. Full article

Background: Amorphous drug formulations are commonly used to improve the solubility and bioavailability of poorly soluble molecular pharmaceuticals, yet less is known about their molecular conformations and local bonding interactions than their crystalline phases. Methods: High-energy X-ray diffraction structure factor measurements have been made on liquid and glassy nifedipine (NIF), felodipine (FEL), NIF 1:3 polyvinylpyrrolidone (PVP), and FEL 1:3 PVP wt.% mixtures. The corresponding X-ray pair distribution functions have been interpreted using empirical potential structure refinement using different models and density functional theory conformer calculations. Results: In both NIF and FEL, the NH···O inter-molecular hydrogen bonds between the pyridyl nitrogen and ester carbonyls are found to be considerably weaker than those observed in the crystalline polymorphs. For nifedipine, it is proposed that either inter-molecular NH…ON nitro bonds are present and/or a fraction (<20%) of conformational changes, with the aryl ring flipped, occur in the liquid state. For felodipine, the models indicate significant disorder associated with the methyl and ethyl side chains in the liquid state, with the main peak intensity at 3.0 Å arising from intra-molecular Cl-Cl atom pairs. When nifedipine molecules are incorporated into PVP, our models show they possess stronger NH···O bonds to the PVP polymer than felodipine molecules, which have stronger affinity for bonding to the polymer than to other felodipine molecules. Conclusions: The amorphous forms of both NIF and FEL show much weaker hydrogen bonding than found in their crystalline phases. Liquid NIF also exhibits configurations which are not observed in the crystal phases. Full article