Separations, Volume 10, Issue 9 (September 2023) – 58 articles

Magnetite nanoparticles (Fe₃O₄) have been utilized to mediate Fumaria officinalis L., a plant known for its rich source of various phytogredients such as diterpenes, nor-diterpenoids, tri-terpenoids, flavonoids, and phenolic acids. These natural compounds act as capping, reducing, and stabilizing agents, offering an affordable and safer approach to synthesize nanoparticles in line with sustainable and eco-friendly concepts, such as green nanoparticles. The cost-effective synthesized nanoparticles were employed to adsorb Pb(II) from an aqueous solution. For investigating the surface characteristics of the adsorbent, a range of techniques were employed, including Field Emission Scanning Electron Microscope (FE-SEM), Fourier Transform Infrared Spectroscopy, and X-ray Diffraction. Fourier Transform Infrared (FT-IR) spectroscopy was specifically applied to discern the functional groups present within the compounds. To optimize the adsorption process and achieve the best removal efficiency (R%), several parameters, including pH, initial concentration, temperature, and contact time, were optimized using the Response Surface Methodology (RSM). The experimental results indicated that the Langmuir isotherm provided a well-fitted model, suggesting a monolayer of Pb(II) capping on the surface of magnetite nanoparticles, with a maximum adsorption capacity of 147.1 mg/g. Moreover, the kinetic findings demonstrated a strong alignment with the pseudo-second-order model. The computed (qe) and observed outcomes associated with the pseudo-second-order kinetic model exhibited a commendable concurrence, underscoring the model’s remarkable precision in forecasting the adsorption mechanism of Pb(II) within the examined parameters. The antioxidant activity and green nanocomposite properties were determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and standard analytical methods. The phytochemical profile exhibited a total phenolic content of 596 ± 0.001 mg GAE/g dry weight and a total flavonoid content of 18.25 ± 0.001 mg QE/g dry weight. The DPPH radical’s inhibition showed potent antioxidant activity at various concentrations (44.74, 73.86, 119.791, and 120.16% at 200, 400, 600, and 800 μg/mL, respectively), demonstrating the potential of the plant as a natural capping and reducing agent during the green process of nanoparticle formation. Full article

Idebenone (IDB) (2,3-dimethoxy-5-methyl-6-(10-hydroxydecyl)-1,4-benzoquinone) is a compound synthesized in the early 1980s. Initially developed for the treatment of cognitive disturbances and Alzheimer’s disease, IDB is now studied for Friedreich’s ataxia, Leber’s hereditary optic neuropathy (LHON), or Duchenne muscular dystrophy. The greatest disadvantage of IDB is its low solubility in water, resulting in low bioavailability. Galenic preparations of IDB in customized doses are common for pediatric patients, which can often prove to be the only option for access to therapy. As an antioxidant, the chemical stability of IDB is an essential guarantee for exerting the desired antioxidant action. Stability studies are essential to know the effect of storage conditions of a galenic product. For the first time, a stability-indicating LC-MS method has been developed to define the stability of IDB suspensions in SyrSpend^® Sugar-Free Unflavored (Fagron), a carrier phase formulated for setting up suspensions of active pharmaceutical ingredients (APIs) insoluble or poorly insoluble in water and compatible with it. The proposed method was validated for linearity, accuracy, specificity, robustness, matrix effect and recovery, limit of detection (LOD), limit of quantification (LOQ), and repeatability. Full article

Organic solvent nanofiltration (OSN) is a membrane separation method that has gained much interest due to its promising ability to offer an energy-lean alternative for traditional thermal separation methods. Industrial acceptance, however, is held back by the slow process of membrane screening based on trial and error for each solute-solvent couple to be separated. Such time-consuming screening is necessary due to the absence of predictive models, caused by a lack of fundamental understanding of the complex separation mechanism complicated by the wide variety of solute and solvent properties, and the importance of all mutual solute-solvent-membrane affinities and competing interactions. Recently, data-driven approaches have gained a lot of attention due to their unprecedented predictive power, significantly outperforming traditional mechanistic models. In this review, we give an overview of both mechanistic models and the recent advances in data-driven modeling. In addition to other reviews, we want to emphasize the coherence of all mechanistic models and discuss their relevance in an increasingly data-driven field. We reflect on the use of data in the field of OSN and its compliance with the FAIR principles, and we give an overview of the state of the art of data-driven models in OSN. The review can serve as inspiration for any further modeling activities, both mechanistic and data-driven, in the field. Full article

This study aims to develop a fast and eco-friendly liquid chromatography–mass spectrometry (LC-MS) method for the determination of aesculin and aesculetin in Cortex Fraxini. Ultrapure water was used as the solvent during the microwave-assisted extraction process to prepare the Cortex Fraxini sample. This extraction method reduces the cost of the harmful solvent (only ultrapure water was used) and microwave extraction time (1 min). The LC separation was conducted using an Agilent InfinityLab Poroshell 120 EC-C₁₈ column (2.1 mm × 30 mm, 2.7 µm) with a mobile phase consisting of 0.1% formic acid and acetonitrile (90:10, v/v) at a flow rate of 0.6 mL/min. Isocratic elution was employed, and the analytes were detected by MS. Through careful optimization and selection of LC-MS conditions, the analysis time was reduced to 1 min, demonstrating the method’s efficiency. The developed method was validated and exhibited excellent specificity, linearity, limit, precision, accuracy, and stability in quantifying aesculin and aesculetin in the Cortex Fraxini samples. The analysis result revealed the presence of aesculin (ranging from 3.55 to 18.8 mg/g) and aesculetin (ranging from 1.01 to 16.2 mg/g) in all ten batches of Cortex Fraxini samples. Compared to the reported LC methods, this approach substantially reduces the total analysis time and requires a minuscule volume of organic solvents. An “Analytical Eco-Scale” assessment was used to evaluate the different assay methods of Cortex Fraxini. The current LC-MS method scored an impressive 90; it was better than the other four reports’ LC methods. Thus, the developed LC-MS method is rapid and green, which is helpful for the quality evaluation of Cortex Fraxini. Full article

The main purpose of the current research was to determine the impact of cumin and green tea on the pharmacodynamics and pharmacokinetics of amlodipine in hypertensive rats. Wistar rats were given 40 mg/kg of L-NAME orally every day for two weeks in order to induce hypertension. The groups treated with herbs received L-NAME with a daily oral dose of cumin (200 mg/kg) and green tea (200 mg/kg), respectively. After the treatment for 14 days, blood pressure was measured at specific intervals using a tail-cuff BP-measurement device for 24 h. For oral pharmacokinetics of amlodipine (single dose, 1 mg/kg), the blood samples were collected at predetermined intervals up to 24 h, and plasma samples were analyzed using UPLC-LC MS/MS. In comparison to the hypertensive control group, green tea and cumin significantly decreased systolic and diastolic blood pressures, as well as mean arterial pressures. Green tea has demonstrated a more prominent effect on pharmacodynamic of amlodipine compared to cumin. The rats treated with amlodipine, cumin + amlodipine, and green tea + amlodipine exhibited AUC_0-t of 38.85 ± 14.8 ng h/mL, 52.05 ± 10.2 ng h/mL, and 114.73 ± 24.94 ng h/mL, respectively. In addition, it has been observed that co-administration of green tea and cumin increases the C_max and T_1/2 of amlodipine. The results indicated a potential interaction between amlodipine and the investigated herbs in hypertensive rats. Hence, precautions should be taken while concurrently administrating amlodipine with the investigated herbs. Full article

The presence of synthetic industrial dyes in the environment poses significant risks to aquatic ecosystems, human health, and economies. This study aims to synthesize iron oxide nanoparticles (IONPs) using a green method, analyze them using physicochemical techniques, and examine the effectiveness with which they photocatalytically degrade crystal violet dye in sunlight. Fourier transform infrared spectroscopy (FTIR) analysis revealed that the biogenic IONPs showed a UV peak at a wavelength of 241 nm, with functional groups including phenols, alkynes, and alkenes. X-ray diffraction (XRD) analysis confirmed the amorphous nature of the bioinspired IONPs. The mean diameter of the biogenic IONPs was 49.63 ± 9.23 nm, and they had a surface charge of −5.69 mV. The efficiency with which the synthesized IONPs removed the crystal violet dye was evaluated under dark and sunlight conditions. The removal efficiency was found to be concentration and time dependent, with a peak removal percentage of 99.23% being achieved when the IONPs were exposed to sunlight for 210 min. The biogenic IONPs also demonstrated antioxidant activity, with a relative IC₅₀ value of 64.31 µg/mL. In conclusion, biogenic IONPs offer a viable and environmentally friendly approach for eradicating industrial synthetic dyes and remediating contaminated environments and aquatic ecosystems. Full article

When a suspension passes through a high-frequency standing sound wave, the particles it contains are manipulated by acoustic forces. In a one-dimensional sound field, these forces lead to a planar arrangement of the particles and the formation of agglomerates. It is known that the combination of these forces and depth filtration can be utilized to significantly increase the filter efficiency of coarse-pored media. So far, this concept has only been used in microfluidics. In this paper, we present the results of a scaled-up filtration channel to test the viability of the industrial application of acoustically assisted filtration systems for the removal of microparticles. The influences of acoustic power input, flow rate, and the porosity of the filter media are investigated. In addition to verifying the scalability, a significant decrease in the large particle fraction in the outflow of the channel was observed when a high-power sound field is applied. Furthermore, the formed agglomerates tend to rise to the fluid surface. The floating particles mostly consist of a large particle fraction. Full article

Aqueous two-phase flotation (ATPF) is an integrative downstream method for separating and concentrating biomolecules from crude biosuspensions such as fermentation broth. Its continuous operation not only increases throughput, but also makes it recommended for continuous upstreams. In this work, an optimized apparatus design in the form of a horizontal flotation tank is presented. The geometry of the new apparatus for continuous ATPF is optimized using flow simulations so that the two aqueous phases can be pumped uniformly through the flotation tank in co-current or counter-current flow. The implementation of a conductivity measurement enables to characterize the phase mixing effect induced by the rising gas bubbles introduced through three different gassing units. ATPF experiments with the model enzyme phospholipase A₂ show that there are favorable combinations of gas flow rates to increase the flotation rate and reduce the back-diffusion at the outlet of the apparatus. This allows high phase exchange rates up to 2/h and hence increases the amount of enzymes that can be recovered per time. Co-current operation of continuous ATPF increased separation efficiency about 14% up to E = 74% compared to counter-current operation. Full article

Brown corundum dust, which is created during the manufacturing of brown corundum using bauxite as the raw material, is a vital carrier of gallium. To ascertain the presence of the contained gallium, the brown corundum dust was measured and characterized (XRF, XRD, ICP-OES, EPMA, SEM-EDS, etc.). Gallium was extracted from the brown corundum dust using a one-step alkali leaching process, and thermodynamic calculations were utilized to assess the viability of the leaching reactions. The effects of leaching parameters (NaOH solution concentration, leaching time, leaching temperature, solid–liquid ratio and stirring speed) on the recovery of gallium during the leaching process were investigated. A gallium recovery of 96.83% was discovered to be possible with the following parameters: 200 g/L of NaOH, 363 K for the leaching temperature, 60 min for the leaching time, 1:10 g/mL for the solid–liquid ratio, and 850 rpm for the stirring rate. Gallium extraction was negatively impacted by raising the leaching temperature above 363 K and the concentration of NaOH solution above 200 g/L due to the accelerated side reactions between Na⁺, K⁺, SiO₄⁴⁻ and AlO₂⁻, which led to the precipitation of aluminosilicates that absorbed gallium from the solution. The influences of leaching parameters such as the temperature, NaOH solution concentration, and solid–liquid ratio on the leaching kinetics were examined. It was demonstrated that the leaching process followed the unreacted shrinking core model, that the interfacial diffusion associated with the contacting surface area served as the controlling step, and that the apparent activation energy was 42.83 kJ/mol. It turned out that the final kinetic equation was 1/(1 − α)^1/3 − 1 = 4.34 × 10⁴ × (C_NaOH)^2.12 (L/S)^0.43exp[−42835/(RT)] t. Full article

This study investigates uranium solvent extraction under AMEX process conditions. The use of pure extractants without diluents or phase modifiers allows us not only to reduce the use of volatile organic compounds but also to provide higher extraction yields without third-phase formation. Pure extractants are protonated amines or quaternary ammoniums with suitable counter ions, which act at the interface between ion pairs and protic ionic liquids. The mixture of sulphates anion (SO₄²⁻) and bis(trifluoromethanesulfonyl)imide anion (NTf₂⁻) revealed unexpected nonlinear extraction behaviors, which appear highly important to rationalize for optimized application. A spectroscopic analysis (NMR, UV-vis, FT-IR, and EXAFS) showed that uranium extraction occurs via a protonated amine and three sulphates. A nonlinear extraction could further be interpreted by considering a water and acid transfer between the two phases: at lower sulphate ratios, the release of acid from the organic phase into the aqueous phase was shown to influence the number of protonated amines in the organic phase, affecting uranium extraction before its enhancement. Furthermore, the extraction loss at higher sulphate ratios was assigned to the destabilization of bidentate uranium–sulphate complexes due to a competition between water and sulphates. Full article

Objective: This study aimed to provide data for the type and content of linear furocoumarins (FCs) in Angelica dahurica (AD) in order to assess their cumulative risks and provide a scientific basis for the rational use and quality evaluation of the medicinal AD to improve public health. Methods: A UPLC method was developed for the simultaneous determination of nine FCs initially by using imperatorin (Im) as the internal standard substance, including Im, phellopterin (Ph), isoimperatorin (Is), oxypeucedanin hydrate (Oh), byakangelicin (Bn), xanthotoxin (8-MOP), bergapten (5-MOP), byakangelicol (Bl), and oxypeucedanin (Op) in two species of Angelica dahurica (AD). And, the risk assessment for the total FCs in AD was explored using the hazard index combined with the toxic equivalency factor (TEF-HI) strategy for the first time. Results: The established method revealed acceptable applicability, and there were no significant differences compared with the external standard method (ESM). The quantitative results demonstrated that the total content of FCs in Angelica dahurica (BZ) were higher than that in Angelica dahurica var. formosana (HBZ), and there was a great difference between the Bl and Op. Moreover, the risk assessment data revealed that the risk of total FCs in AD to human health was low. Conclusions: The established UPLC method that determined nine FCs in AD using a single marker could solve the problem of difficulty in obtaining a chemical reference substance with high purity and requiring a long determination time. And, the TEF-HI risk assessment approach associated with FCs in ADs could guide the rational utilization of toxic FCs in ADs in the progress of improving public health safety. In short, the whole systematic strategy provides a scientific basis for rational quality evaluation and the healthy use of related herbal medicines. Full article

Bioflocculants can be used for cost-effective harvesting of microalgae biomass on an industrial scale. This study investigates the flocculation-based harvesting approach to recovering Chlorella vulgaris microalgae biomass using chitosan biopolymer. Response surface methodology (RSM) was used to design the experiments and optimize the critical operating parameters. Box-Behnken Design (BBD) was employed at three levels, and 17 experimental runs were conducted to determine the optimal conditions and the relationship between operating parameters. The highest biomass recovery of 99.10% was achieved at the following optimized conditions: pH of 5, flocculation time of 45 min, and chitosan concentration of 10 mg/L. Both experimental results and model outputs indicated that pH significantly impacts microalgae harvesting and that process performance is less dependent on chitosan concentration and flocculation time. The quadratic model has shown the best fit with the experimental results. The results could be applied to large-scale microalgae harvesting applications to promote microalgae biomass recovery and reduce operating costs. Full article

Rapid growth in various industrial fields has introduced a series of new environmental risks. The textile industry is one of the major industries that is influenced by rapid advancements in technological sectors. The development in textile dying technologies has presented new types of dyes that are toxic to the ecosystem. Azo dyes are the main artificial dyes used in textiles, food, and other applications. Typically, these dyes are introduced into the environment as wastewater discharged from factories. The discharged influence penetrates the ecosystem and causes deadly diseases to human and animals. Several studies present activated carbon as a proper solution to eliminating the presence of azo dyes in the environment. However, various types of azo dye have different properties and chemical structures. Thus, there is a crucial need for more studies on the application of activated carbons to eliminate the presence of azo dyes in the environment. This paper discusses the toxic effects of azo dyes on the environment and human health. Moreover, this work presents a general review of the preparation of activated carbon and the parameters that influence the adsorption performance. Full article

Poly(methyl methacrylate) (PMMA) is characterized by high CO₂ capture yield under mild pressures and temperatures. A morphological modification of powdery amorphous PMMA (pPMMA) is carried out by electrospinning to increase the surface/volume ratio of the resulting electrospun PMMAs (ePMMAs). This modification improves the kinetics and the capture yields. The rate constants observed for ePMMAs are two to three times higher than those for pPMMA, reaching 90% saturation values within 5–7 s. The amount of sorbed CO₂ is up to eleven times higher for ePMMAs at 1 °C, and the highest difference in captured CO₂ amount is observed at the lowest tested pressure of 1 MPa. The operating life of the ePMMAs shows a 5% yield loss after ten consecutive runs, indicating good durability. Spent electrospun PMMAs after several cycles of CO₂ sorption-desorption can be regenerated by melting and again electrospinning the molten mass, resulting in a CO₂ capture performance that is undistinguishable from that observed with fresh ePMMA. Scanning electron and atomic force microscopies show a reduction in surface roughness after gas exposure, possibly due to the plasticization effect of CO₂. This study shows the potential of electrospun PMMAs as solid sorbents for carbon capture from natural gas or pre-combustion and oxyfuel combustion processes. Full article

In this paper, a rapid and efficient method for the preparation of scopolamine hydrobromide with high purity was established, named as magnetic field-induced crystallization. Based on the difference in solubility between scopolamine and scopolamine hydrobromide, salifying crystallization was selected and then treated with the synergistic effect of magnetic field to achieve the goal of purifying scopolamine. The influence of crystallization solvents and magnetic field intensity on the crystallization process of scopolamine hydrobromide, as well as the impact of magnetic field on the crystal growth direction, were investigated. The results revealed that treatment under magnetic field led to a shortened induction time (25.64–75.46%), an increased purity of crystals (0.95–2.92%), and an enhanced recovery rate (4.51–10.78%). Furthermore, it was also discovered that magnetic field could destroy hydrogen bonds within the solution, and change the physical properties of the mother liquid, so as to promote the nucleation formation and crystal growth. These findings suggested that external magnetic field could be a promising method for scopolamine preparation. Full article

Due to their ease of collecting and transporting from the field and their ability to accumulate pollutants, bird feathers are increasingly being used as a non-invasive biomonitoring tool for environmental monitoring programs. Polycyclic aromatic compounds (PACs) are a diverse class of environmental pollutants, and because of their deleterious impacts on biological species, monitoring these compounds in wildlife is of high importance. Current approaches to measuring PACs in bird feathers involve a time-consuming acid treatment with a concomitant solvent extraction step. Here, a validated method for measuring a suite of PACs in bird feathers using pressurized fluid extraction and identification and quantitation by gas chromatography-tandem mass spectrometry is presented. Chicken (Gallus domesticus) feathers were purposely fortified with a suite of 34 PACs separately at three fortification levels and placed inside a pressurized fluid extraction cell containing silica gel/deactivated alumina to provide in situ clean-up of the sample. Except for anthracene and naphthalene, the accuracy of our method ranged for PAHs from 70–120% (irrespective of fortification level), and our intra- and inter-day repeatability was smaller than 28%. For APAHs, our accuracies ranged from 38–158%, and the inter- and intra-day repeatability was less than 35%. Our limits of detection and quantitation for both groups of compounds ranged from 0.5–13 and 1.5–44.3 ng/g, respectively. Overall, the developed method represents an effective and efficient approach for the extraction and quantitation of PACs from bird feathers that negated the need for the time-consuming and potentially harmful acid treatment. Full article

Lysergic acid diethylamide (LSD) is a powerful hallucinogen. Its detection is limited by its low dosage; moreover, LSD is rapidly metabolized into 2-oxo-3-hydroxy-LSD (O-H-LSD). In this study we validated two methods for determination of LSD and O-H-LSD in blood. Method #1 consisted in the upgrade of a previously developed procedure for detection of 163 compounds. Method #2 was specific for LSD and O-H-LSD. Analyses were performed through LC-MS/MS by dynamic (#1) and/or MRM mode (#2), in positive ionization. Transitions were: 324→223,208 m/z for LSD; 356→237,222 m/z for O-H-LSD. Validations were performed following the AAFS’s guidelines. Linearity was good for both methods. Sensitivity was in line with previously validated methods with LOQs at 0.0375 (#1) and 0.025 (#2) ng/mL for LSD and 0.01875 (#1) and 0.0125 (#2) ng/mL for O-H-LSD. Bias and %CV always met the acceptance criteria. RRs were >83%, except for O-H-LSD with method #1. The methods were successfully applied to two real cases. Method #1 proved to be useful for screening purposes, while method #2 can represent a sensitive and reliable tool for confirmation procedures. Full article

Emerging contaminants are being detected at a high frequency, posing significant environmental and human health challenges. This study aimed to investigate the potential of using commercial granular activated carbon for adsorbing nine aqueous emerging contaminants (carbamazepine, phenacetin, pentoxifylline, norfloxacin, iprobenfos, isoprothiolane, metolachlor, tebuconazole, and hexaconazole). The adsorption study involved employing kinetic and isotherm models, using various concentrations of emerging contaminants and sorbents in a batch system. Additionally, the study explored the correlation between the characteristics of emerging contaminants and their adsorption values, which displayed a relatively linear relationship. While some previous papers have evaluated the performance of one or two substances, there is a lack of research on the adsorption mechanisms of all nine aqueous emerging contaminants. Therefore, the findings from this study on the adsorption potential of granular activated carbon can serve as a valuable foundation for further investigations into its effectiveness in adsorbing emerging contaminants. Full article

Cannabis contains a wide range of terpenes and terpenoids that are mainly responsible for their distinctive aroma and flavor. These compounds have also demonstrated therapeutic effects either alone and/or as synergistic compounds with other terpenes, terpenoids, and/or cannabinoids. Several studies have attempted to fully characterize terpenes and terpenoids in cannabis; however, most of these studies used one-dimensional gas chromatography, which often results in the co-elution of the compounds. In the present study, we analyzed terpenes and terpenoids in the dried flowers of six cannabis strains using a two-dimensional gas chromatograph time-of-flight mass spectrometer (GC × GC-TOFMS). A total of 146 terpenes and terpenoids were detected across all six cannabis strains with an enhanced separation of 16 terpenes and terpenoids in the second dimension. Additionally, we achieved enhanced separation of four terpenes and terpenoids from a standard mixture in the second dimension. Chemical differences were observed in the number and relative abundance of monoterpenes, monoterpenoids, sesquiterpenes, and sesquiterpenoids in all six strains. We were also able to identify four new terpenoids in cannabis, which are reported here for the first time. Full article

Owing to the unified and tunable pore size, two-dimensional graphyne membranes show excellent performance in the realm of gas transport and separations. The impacts of environmental conditions on the pore size of a porous membrane are ignored in previous studies. Using molecular modeling techniques, we here probe the accessible pore size of the $\gamma$-graphyne membrane under various pressure and temperature conditions. First, by assessing the gas permeation through the two-dimensional $\gamma$-graphyne membrane at a constant temperature, the accessible pore size of this membrane is shown to be proportional to the driving force—the pressure difference between the two sides of the porous membrane. Such a driving force dependence is found to be well described by a simple asymptotic model. Then, by determining such pressure dependence at two different temperatures, temperature is found to show a weak influence on the accessible pore size. Finally, by considering the binary mixed gases of various mole fractions, the accessible pore size measured using one of the two species is shown to be dependent on its partial pressure difference. These findings for the accessible pore size, which highlight the tunable pore size by altering the driving force, can be expected to provide a practical strategy to rationalize/refine the pore size of the porous membrane for gas transport and separations, especially for two molecules with similar diameters. Full article

Because of their excellent properties, glass-ceramics have been widely developed and applied in many fields, and there are many potential application values to be disseminated. The preparation of glass-ceramics from industrial slag and metallurgical waste provides a new way for the comprehensive utilization of solid waste. Coal gangue is the largest of all kinds of industrial waste slag, while iron tailings and high-carbon ferrochrome slag also occupy a large proportion of China’s industrial solid waste. With cheap industrial solid waste as the main raw material, the production of high-value-added glass-ceramics can reduce pollution, protect the ecological environment, and have good economic and social benefits. Cordierite glass-ceramics were prepared using the sintering method with coal gangue, iron tailings, and high-carbon ferrochrome slag as the main raw materials. Meanwhile, an iron silicon alloy containing chromium was obtained. The heat treatment system of basic glass was determined by differential scanning calorimetry (DSC), and the sintered product was analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). An orthogonal test was used to analyze the effects of the mass of basic glass powder, molding pressure, and holding time on the grain size and crystallinity of the samples. The hardness, acid and alkali resistance, density, and water absorption of the sintered products were determined. The results show that the main crystal phase of the prepared glass-ceramics is cordierite. The optimal combination for the green body is “basic glass powder mass 6 g, molding pressure 35 MPa, holding time 10 min”. The properties of glass-ceramics are good. At the crystallization temperature of 970 °C, the Vickers hardness is up to 866 HV, and the bulk density is up to 2.99 g/cm³. This study may provide a useful reference for the treatment of industrial solid waste. Full article

Many non-traditional isotopes, such as chlorine, magnesium, calcium, etc., are widely used as groundwater tracers. A new sample processing protocol of purification and concentration for isotopic analysis is presented to overcome many of the major drawbacks of existing methods. Contemporary sample preparation often requires several laborious off-line procedures in a ultra clean laboratory prior to instrumental determination; additionally, interference ions in real samples are difficult to completely remove, especially when the concentration of those ions is equal to that of the target ions. The new protocol includes the following steps: (i) one-step purification using a newly developed isotopic preparative chromatograph (IPC) with a background suppressed mode to obtain extremely pure components that only have target ions and H₂O; (ii) enrichment of the collected pure solution from the previous step using a newly developed ultra clean concentrator filled with high purity nitrogen; (iii) transforming the enriched target ion into suitable speciation inside the ultra clean concentrator; (iv) finally, sending the enriched solutions to a multi-collector inductively coupled-plasma mass-spectrometer (MC-ICP-MS) or thermal ionization mass spectrometer (TIMS). The present method was validated using certified reference materials and real samples for both chlorine and magnesium; the precision of chlorine ratio value was generally below 0.22‰ and that of Mg was below 0.12‰. This processing protocol provides a potential method for isotope sample preparation and analysis in a small number of geological samples with low concentrations of many other elements or compounds such as nitrate, sulfate, lithium, calcium, strontium, etc. Full article

A new oligostilbene trimer, malaysianol F (1), together with ten known stilbenes (2–11), were successfully separated and purified from the acetone extract of the lianas of Gnetum microcarpum. Malaysianol D (2) was isolated for the first time in Gnetum plants. The tanninless crude extract (52.5 g) was fractionated using a vacuum liquid chromatography (VLC) technique to give five major fractions. Fraction 2 (4.68 g), 3 (4.79 g) and 4 (9.29 g) were all subjected to further isolation and purification using VLC, column chromatography (CC) and repetitive radial chromatography (RC) techniques with the best solvent system to yield malaysianol F (1) (6.2 mg), malaysianol D (2) (62.5 mg), malaysianol E (3) (2.4 mg), ε-viniferin (4) (10 mg), resveratrol (5) (6.5 mg), gnetol (6) (3.5 mg), gnetucleistol C (7) (12.2 mg), isorhapontigenin (8) (8 mg), cuspidan B (9) (3.2 mg), parvifolol D (10) (4.8 mg) and gnetifolin M (11) (2.5 mg). Their structures were determined on the basis of the analysis of spectral evidence by extensive NMR data analyses and comparison with the related published data. Several compounds were tested for anti-inflammatory activity. Their inhibitory effect on Prostaglandin E₂ (PGE₂) was tested using radioimmunoassay techniques. Compound 6 exhibited significant concentration-dependent inhibitory effects on PGE₂ production with IC₅₀ values of 1.84 µM comparable with the positive control, indomethacin (IC₅₀ 1.29 µM). Full article

The release of 1,4-dioxane probably contributes to the deterioration of marine habitats, animal health, and human liver and kidneys. The formulation of 1,4-dioxane in glycols, which has been applied for dehumidifying agents in refineries, may need to be replaced to ensure public health. Further, it is necessary to identify and precisely determine the levels of 1,4-dioxane in glycols for food quality control and environmental safety regulation. The objectives of this study were to validate a liquid–liquid extraction (LLE) method for 1,4-dioxane analysis and to optimize the LLE conditions using a response surface methodology (RSM). With consideration of the food matrix and its applications, polyethylene glycol 200 was used as the model system and analyzed by gas chromatography with flame ionization detection. In the experiments for the optimum extraction temperature and time of 1,4-dioxane in ultrasonic treatment, they were 20 °C and 10 min, respectively. The experimental conditions and results were analyzed by RSM with the Box–Behnken design, and the optimal extraction conditions for the LLE were determined to be coded with three independent variables (sample weight, solvent volume, and centrifugation speed). The amount of 1,4-dioxane increased as the amount of sample increased, whereas the amount of 1,4-dioxane decreased as the amount of solvent increased. This information can help to find the analytical methods for regulating the 1,4-dioxane content and its precise quantification in food products. Full article

Entrectinib is an oral selective inhibitor of the neurotrophic T receptor kinase (NTRK). It is used in the treatment of solid tumors in NTRK gene fusion lung cancer. The study aimed to develop and validate an analytical method for quantifying entrectinib plasma by UPLC-MS/MS using quizartinib as an internal standard. The method involves liquid–liquid extraction of entrectinib from plasma using tert butyl methyl ether. The mass-to-charge transitions were 561.23 → 435.1 for entrectinib and 561.19 → 114.1 for quizartinib. The method was successfully validated according to ICH and FDA guidelines. The method has a low quantification limit of 0.5 ng/mL, and the calibration curves constructed over a wide range of 0.5–1000 ng/mL showed good linearity (≥0.997). This method exhibits a tenfold increase in sensitivity compared with the previous method. The method is also accurate, precise, and reproducible, as evidenced by the inter-day and intra-day accuracy and precision values of 82.24–93.33% and 3.64–14.78%, respectively. Principles of green analytical chemistry were considered during all analytical steps to ensure safety. The greenness of the methods was evaluated using two assessment tools. These tools are the Analytical Eco-Scale and the analytical greenness metric approach (AGREE). The results were satisfactory and compatible with the criteria of these tools for green assessment. This method is green, accurate, precise, and reproducible. The method can be used to quantitate entrectinib in plasma and its pharmacokinetics in preclinical, and therapeutic drug monitoring. Full article

The development of cost-effective technologies for the treatment of water contaminated by petrochemicals is an environmental priority. This issue is of paramount importance for countries like Saudi Arabia owing to its scarce water resources. Of particular concern are automobile fuels, such as gasoline and diesel, that can contaminate water aquifers from leaking underground fuel storage tanks. Owing to the cost-effectiveness of adsorption-based technologies, low-cost high surface-area commercial activated carbon was used for the adsorptive removal of contaminants from the emulsified fuel-contaminated water. Batch equilibrium experiments showed a high efficacy of the adsorbent. Even with small amounts of the adsorbent, a removal efficiency of more than 97% was obtained for both gasoline as well as diesel. Three different well-known batch adsorption isotherm models, namely the Langmuir, Freundlich, and Temkin, were used for describing the experimental data. The best results were obtained using the Freundlich isotherm followed by the Langmuir model. The maximum capacity was found to be 8.3 g gasoline and 9.3 g diesel per gram of the adsorbent at ambient conditions for a neutral contaminated aqueous solution. Full article

This study investigates the adsorption of methanol, water, and their mixture in a hybrid silica stationary phase with supercritical carbon dioxide as a mobile phase in supercritical fluid chromatography (SFC). The adsorption isotherms of methanol and water were determined by two dynamic methods: the elution by characteristic point (ECP) method and the inverse method (IM). Both the single-component and competitive bi-Langmuir models were pre-selected for the inverse method. The initial parameters of the single-component isotherm for both methanol and water were estimated with the ECP method by fitting the experimental data to the bi-Langmuir isotherm model. Then, using the inverse method, we refined the single-component isotherm parameter values, which were then further used for determining the competitive isotherm of the methanol–water mixture. The elution profile of the (methanol–water) mixture sample was calculated by the equilibrium-dispersive (ED) model. The results indicated that there is a good agreement between the experimental band profile and the calculated band profile, which was obtained from the parameters of the competitive bi-Langmuir isotherm model, revealing a competition between methanol and water to reach the adsorption sites. Furthermore, the saturation capacity of the adsorption sites in the stationary phase decreased in the case of the mixture sample compared to those for the single-component sample. Full article

Ignitable liquid residue (ILR) samples play an important role in fire investigations. Similar to other types of forensic evidence, maintaining sample integrity depends on the prevention of cross-contamination during both storage and transport. This study examines cross-contamination in ILR samples on various sample matrices (gravel, soil, wood). After inducing leaks in a controlled environment, sample analysis by GC×GC-ToF MS allowed for sensitive detection and in-depth characterization of cross-contamination processes. The potential for false positive identification of ILR is notably present due to cross-contamination. Compound transmission for a mid-range ILR (gasoline), for instance, was detectable after a 1 h exposure, with a complete profile transfer occurring after 8 h regardless of the matrix type. Visual comparisons and uptake rate calculations further confirmed matrix interaction effects taking place in the form of inherent native compound interference and adsorbate–adsorbate interaction during transmission and extraction processes for soil and wood matrices. Chemometric analysis highlighted the advantage of employing statistical analysis when investigating samples under matrix interactions by identifying several statistically significant compounds for reliably differentiating cross-contamination from background and simulated positive samples in different volatility ranges and compound classes. Untargeted analysis tentatively identified three additional compounds of interest within compound classes not currently investigated in routine analysis. The resulting classification between background, contaminated, and simulated positive samples showed no potential for false positive ILR identification and improved false negative errors, as evidenced by classification confidences progressing from 88% for targeted and 93% for untargeted to 95% for a diagnostic ratio analysis of three ratios deployed in tandem. Full article

Heavy metal pollution in rivers and lakes arising due to rapid economic development has been extensively studied by various countries due to its direct impact on ecological health and human well-being. However, there is a lack of comprehensive and systematic reviews addressing the current research status of this subject. In this study, we conducted a visual metrological analysis of the literature from 2001 to 2021 using the Web of Science (WoS) and China National Knowledge Infrastructure (CNKI) citation databases. The results show that studies conducted in other countries initially outnumbered those in China; after 2010, China emerged as the foremost contributor. Furthermore, both the WoS and CNKI databases indicate active engagement of Chinese researchers through a significant proportion of published papers on metal research, with prominent contributions coming from institutions such as the Chinese Academy of Sciences (CAS) and University CAS. Nevertheless, Chinese research institutions still have relatively low total paper citation numbers and have yet to establish themselves as key players in international scientific research efforts. Additionally, core authors from different countries share substantial similarities in their research directions and focuses. Consistent research hotspots regarding heavy metals in rivers and lakes were identified across both databases, including heavy metal pollution, adsorption, human activities, water quality, and sediment. Full article

In the field of contaminated site remediation, risk analyses can be carried out by the use of appropriate mathematical models, based on simplified hypotheses of real sites. The possibility to have shared and accurate analytical methods is an important challenge for both routine laboratories and supervisory institutions. Although official methods (e.g., APH2009) are already available, they are lacking in some aspects, such as applicability to all the different sampling and analysis media and ease of use in routine analysis. Here, we report our recent advances in the implementation of an empirical method for hydrocarbon speciation in an air matrix, previously developed by the authors and published in 2015. The validation results led to a coefficient of variation (CV%) between 10–15% for the hydrocarbon fractions investigated (C₅-C₈ aliphatic, C₉-C₁₂ aliphatic, C₉-C₁₀ aromatic and C₁₁-C₁₂ aromatic) and recovery of ≤20%, in agreement with the required characteristics for the analytical methods. Several real samples were analyzed by the proposed method and the results were compared to those obtained by the official approach. The comparison led to an average bias (that is, the difference between the results from the developed method and those from the conventional one) of about 10%, confirming that the innovative approach is robust, accurate and can be applied to all the analytical media used for air sampling, such as soil gas. Full article