Molar Ratio Research Articles

Inclusion complex of trans-p-coumaroyl-secologanoside (comselogoside) with β-cyclodextrin. Part I. structural characterization and study of solubilization and stabilization.

Comselogoside (COM) is a secoiridoid, derivative of p-coumaric acid with a wide range of potential beneficial properties, although its poor aqueous solubility and low stability limit its study and application. The formation of an inclusion complex with β-cyclodextrin (β-CD) could improve the solubility and photostability of COM. The complexation of COM with β-CD in an aqueous solution has been studied for the first time, using the freeze-drying method with high encapsulation yield and efficiency. The formation of the inclusion complex was confirmed by electrospray ionization (ESI) mass and 1H NMR spectroscopy. Phase solubility studies provided an AN-type diagram with an increase in aqueous solubility by 100% and the formation of a high stoichiometric order complex COM: β-CD. The 1H NMR analysis with different COM/β-CD molar ratio established the formation of the 2:1 stoichiometric complex by Job ҆ s plot. In addition, the complexation of COM with β-CD improved the stability of COM against irradiation with UV light at 254 nm. Finally, combined docking and DFT calculations have been performed to study the formation and interactions of the COM: β-CD complexes. The computational results show excellent agreement with experimental observations.

Microwave-hydrothermal synthesis of calcium borate whiskers: Influencing factors and formation mechanism

The synthesis of whiskers is an important means of high-value utilization of calcium resources. Calcium borate (Ca2B2O5·H2O) whiskers were synthesized by microwave hydrothermal method using CaCl2, Na2B4O7·10H2O and NaOH as raw materials at 140 °C for 2 h. A series of characterizations were conducted on the obtained calcium borate whiskers, including phase identification (XRD and FT-IR), crystal morphology (SEM), crystal structure (TEM and SAED), and thermal stability (TG). Through batch experiments under the control of influencing factors, the effects on product phase and morphology were systematically studied, such as raw material concentration (Ca2+ concentration and the molar ratio of boron/calcium), reaction temperature, holding time and pH value. For the prepared calcium borate whiskers, SAED demonstrated that the whiskers have a single crystal structure, characterized by a sarciniform shape with diameter ranging from 1.2 to 3.1 μm and a length of 50 to 120 μm. And thermal analysis revealed that the calcium borate whiskers remained stable without losing crystalline water at a synthesis temperature of 140 °C, while releasing crystalline water at a temperature range of 383.6 °C to 430.9 °C. The optimal conditions for Microwave-Hydrothermal synthesis were identified based on experimental phenomena, and the solution-liquid–solid (SLS) process of whisker formation was proposed and analyzed. The possible chemical reactions and growth mechanisms of calcium borate whiskers under microwave hydrothermal synthesis were briefly proposed by adjusting the reaction conditions and observing the process of morphological changes.

Hydrodynamic Cavitation – A Promising Technology for Water Treatment

In today's context, water treatment assumes paramount importance due to the scarcity of potable water and the escalating needs of the global population. Hydrodynamic Cavitation (HC) emerges as a promising application in wastewater treatment, particularly when integrated with Advanced Oxidation Processes (AOPs). The study begins with a critical examination of the literature on combined approaches involving hydrodynamic cavitation, followed by experimental findings. The primary objective was to mitigate the chemical oxygen demand (COD) of the sample through HC in conjunction with hydrogen peroxide and Fenton reagent. Subsequently, each run was executed, and the output value obtained from HC was determined. Throughout the research, samples of river water were procured from the Mula-Mutha River in Pune. HC treatment reduced the COD of river water by approximately 60.83 % at 3 pH. Notably, the highest degradation was observed at 9 pH with the use of Sodium persulphate, with the optimal concentration estimated to be 600 ppm. Moreover, a COD reduction exceeding 89 % with a dosage of 15 mM H2O2. Treatment with Fenton reagent for 60 min demonstrated a remarkable COD decrease of up to 93 %, with an optimal H2O2 to FeSO4 molar ratio of 10:1 and at 3 pH. The Fenton procedure alone or in combination with H2O2 and HC proved to be the most efficient for river water characterized by extremely high COD levels, yielding the greatest reduction during experimental trials. The kinetics of HC degradation conformed to a first-order rate law, with the value of a rate constant (K = 7.21 × 10-4 s−1).

Enhanced thermoelectric properties of carbon nanotubes/polyaniline fibers through engineering doping level and orientation

The rapid progress of miniaturized wearable electronics has put forward great requirements for organic fiber-based thermoelectric (TE) generators. Despite polyaniline (PANI) exhibits many outstanding attributes such as facile synthesis and low cost, as well as good environmental and thermal stability, only a few PANI-based fibers were fabricated and their TE efficiency needs to be further improved. In this work, the TE performance of wet-spun carbon nanotubes (CNTs)/PANI fibers was improved by synergistic engineering doping level of PANI and orientation of the fibers. The doping degree was optimized by varying coagulation baths, bath durations, and dopant loadings in the spinning solution, followed by fixing process during air drying to decrease shrinkage and enhance orientation of the fiber. Hexane coagulated CNTs/PANI fibers exhibited a higher doping degree of PANI compared to that of acetone and ethyl acetate, resulting in a maximum TE power factor of 77.4 μW m-1K-2 for 71 wt% CNTs/PANI fibers at PANI/dopant molar ratio of 2:1.25. Further fixing process induced a more oriented structure along the fibers, facilitating carrier transport and contributing to a significantly increased conductivity of 2155 S cm-1. Consequently, the CNTs/PANI fibers reached an optimal power factor of 91.8 μW m-1K-2. With outstanding TE performance and mechanical properties, the resultant fibers were assembled to fabricate a flexible TE generator, which generated a high output power of 2.5 nW with a temperature gradient of 10 K. These results demonstrate the potential of high-performance CNTs/PANI fibers to harvest body heat for the power supply of the wearable electronics.

Fluorinated polymer-derived microporous carbon spheres for CFx cathodes with high energy density

Fluorinated carbon (CFx) compounds have extensive applications in lithium primary battery cathodes owing to their high energy density. In this investigation, a novel CFx compound offering superior electrochemical properties was synthesized via a low-temperature fluorination process, utilizing Pluronic F127 as a template agent and microporous carbon spheres produced through soft template-assisted high-temperature carbonization and chemical activation as precursors, and by regulating the amount of soft template F127 added. The reduction in microsphere size, narrower particle size distribution, and introduction of defects contribute to augmenting the molar ratio of F to C (F/C) of CFx while preserving the electrochemical activity of C-F bonds. The specific capacity of fluorinated polymer-derived microporous carbon spheres (FPMCSs) with a high fluorination degree rivals that of commercial fluorinated graphite (FG). The microsphere morphology and microporous structure not only furnish abundant sites for fluorination reactions in electrode processes but also facilitate Li+ diffusion, ensuring ample rate capability. The synthesized FPMCSs exhibited a peak specific capacity of 1079 mAh g–1 and a maximum energy density of 2679 Wh kg–1 (substantially surpassing the 2180 Wh kg–1 of commercial FG). Hence, the prepared FPMCSs underscore the significance of selecting suitable carbonaceous materials and designing structures deliberately, showing promising potential for achieving high energy density in CFx cathodes in the future, employing readily available and cost-effective raw materials.

Bulk Nanostructure of Mixtures of Choline Arginate, Choline Lysinate, and Water.

Neutron diffraction with empirical potential structure refinement was used to investigate the bulk liquid nanostructure of mixtures of choline arginate (Ch[Arg]), choline lysinate (Ch[Lys]), and water at mole ratios of 1Ch[Arg]:1Ch[Lys]:6H2O (balanced), 1Ch[Arg]:1Ch[Lys]:20H2O (balanced dilute), 3Ch[Arg]:1Ch[Lys]:12H2O (Arg- rich), and 1Ch[Arg]:3Ch[Lys]:12H2O (Lys- rich). The Arg- and Lys- anions tend not to associate due to electrostatic repulsion between charge groups and weak anion-anion attractions. This means that the local ion structures around the anions in these mixtures resemble the parent single-component systems. The bulk liquid nanostructure varies with the Arg-:Lys- ratio. In the Lys--rich mixture (1Ch[Arg]:3Ch[Lys]:12H2O), Lys- side chains cluster into a continuous apolar domain separated from a charged domain of polar groups. In the balanced mixture (1Ch[Arg]:1Ch[Lys]:6H2O), Lys- side chains form discrete apolar aggregates within a continuous polar domain of Arg-, Ch+, and water, and in the Arg--rich mixture (3Ch[Arg]:1Ch[Lys]:12H2O), the distribution of Lys- and Arg- is nearly homogeneous. Finally, in the balance dilute system (1Ch[Arg]:1Ch[Lys]:20H2O), a percolating water domain forms.

Effective and selective Type V deep eutectic solvent based microextraction of E127 in foodstuffs and drugs

The effective and selective deep eutectic solvent (DES) based microextraction method was developed for the first time, using new generation Type V DES for the separation and determination of E127 (erythrosine) in foodstuffs and drugs. Dicyclohexylamine and diphenylamine were mixed at 1:5 mole ratio to create the DES. The essential parameters (pH, DES volume and vortex time) were optimized using Box-Behnken Design of Response Surface Methodology. The quadratic microextraction approach was favorable chemometric model design (R2=0.9945) for the method. The limits of detection and quantitation were determined to be 23 and 78µg/L, respectively. E127 was enriched to be thirty-fold at the optimum conditions. The concentrations of E127, ranging between 0.078 and 4.0µg/mL, were linearly determined using the equation A=62.114C+3.8 (R2=0.9989). The interference effect of ions and dyes was investigated in detail. The relative standard deviation was lower than 6% throughout the experiments. Analyte addition-recovery tests were applied to the real samples for determination of their E127 concentrations. The method was validated by calculating microextraction recoveries obtained from spiked tests. E127 contents of foodstuffs and drugs were determined between 8.8 and 42.4µg/g, with recovery values ranging from 94 to 102%. AGREEmethod and AGREEprep tools were used to define environmentally friendly index of the method.

Melamine sponges incorporated azo-linked porous organic polymer as adsorbent for extraction and determination of six B vitamins using pipette tip micro solid-phase extraction

A novel azo-linked porous organic polymer (AL-POP) was synthesized from caffeic acid and benzidine via an azo-coupling reaction and characterized by FTIR, SEM-EDS, BET, TGA, XRD and zeta potential analysis. AL-POPs were incorporated into melamine sponges and used for pipette tip micro solid-phase extraction (PT-MSPE) of six types of B vitamins (including thiamine, riboflavin, nicotinamide, pyridoxine, folic acid, and cyanocobalamin). After extraction, the samples were analyzed using high performance liquid chromatography-diode array detection (HPLC-DAD) system. The effect of AL-POP composition on the extraction efficiency (EE) of vitamins was investigated and benzidine to caffeic acid mol ratio of 1.5, 3.35 mmol of NaNO2, and reaction time of 8 h were selected as optimum conditions. The efficiency of the extraction process was improved by optimizing various parameters such as the amount of sorbent, pH and ionic strength of the sample, sample volume, number of adsorption and desorption cycles, type of wash solvent, and type and volume of eluent solvent. Linearity (R2≥0.9987), Limit of detection (LOD) (11.88-18.97 ng/mL), limit of quantification (LOQ) (39.62-63.23 ng/mL), and enrichment factor (EF) (1.27-4.31)) were obtained using calibration curves plotted under optimum conditions. Recovery values of these six B vitamins in the spiked multivitamin syrup samples varied from 80.01% to 108.35%, with a relative standard deviation (RSD) below 5.44%. Eventually, the optimized method was successfully used to extract and quantify the B vitamins in multivitamin syrup and non-alcoholic beer.

Fish Tissue Mercury in Lakes and the Moderating Effects of Selenium

Fish mercury concentrations result in fish consumption advisories. However, selenium : mercury molar ratios >1 are protective to wildlife and humans. Therefore, we sampled total selenium (TSe) and total mercury (THg) concentrations and molar ratios in sport fish from 50 Idaho (ID) lakes >20 ha and 67 northeastern USA (NE) lakes >1 ha. Sample lakes were selected at random, to obtain unbiased estimates of mean fish tissue levels, with known confidence limits, for target populations of 95 ID lakes >20 ha in surface area and 12,557 NE lakes >1 ha. Bass and salmonids presented the greatest potential mercury toxicity risk to consumers based on their higher mercury content, desirability as game fish, and widespread distributions. Fish tissue THg exceeded safe consumption criteria in an estimated 20–80% of the lakes in the two regions and TSe exceeded safe consumption thresholds in an estimated 0–20% of the lakes in the two regions. However, the Se : Hg molar ratio was >1 in an estimated 90–97% of fish tested from NE and ID lakes. Therefore, we concluded that Se levels in these systems are usually sufficient to limit disruption of selenoprotein activities by Hg, and that fish consumption advisories based on Hg alone are unnecessarily restrictive.

Co(II) and Ni(II) complexes with bis(4-((E)-(4,5-diphenyl-1H-imidazol-2-yl)diazenyl) phenyl)methane: synthesis, characterization and anti-corrosion effect investigation

Bright coloured Co (II) and Ni (II) complexes of an azo ligand were synthesized. This ligand was previously synthesized from the coupling reaction between 4,5-diphenyl imidazole and 4,4-diaminodiphenylmethane in 1:2 molar ratio (4,4-diaminodiphenylmethane and 4,5-diphenyl imidazole). The synthesis process of the complexes involved the reflux reaction between the azo ligand with both metal salts. The synthesized complexes were characterized by FTIR, UV.-Visible, molar conductivity and atomic absorption. From the obtained characteristic data of the FTIR spectra, the coordination between the two metals and the azo ligand occurs by the coordination with the nitrogen atom of the azo group and one of the nitrogen atoms in the imidazole both rings. The molar conductivity test confirm the non- electrolytic nature of both complexes, while the atomic absorption agrees with the expected complexes formula. Therefore, the octahedral structure for the two complexes is suggested. The anti-corrosion activity of the synthesized compounds were investigated under two temperatures (298 and 308 K) with 0.03 gm of each compound was tested. According to the results cobalt (II) complex shows a better anti-corrosion activity (93%) in comparison with the ligand and nickel (II) complex. KEY WORDS: Cobalt(II) and nickel(II) azo complexes, Imidazole derivative, Anti-corrosion effect Bull. Chem. Soc. Ethiop. 2024, 38(4), 963-971. DOI: https://dx.doi.org/10.4314/bcse.v38i4.12

Synthesis, spectroscopic, biological and structural characterizations for the gold(III), platinum(IV), and Ruthenium(III) ceftriaxone drug complexes

Three new metal complexes of ceftriaxone (cef), incorporating platinum(IV), gold(III), and ruthenium(III), were prepared. The complexes were prepared using a 1:2 molar ratio between ceftriaxone sodium salt (Na2cef) to AuCl3, PtCl4, and RuCl3 salts in methanol solvent. The as-synthesized complexes were characterized using microanalytical techniques for C, H, N, and S elements, magnetic and molar conductance measurements, as well as spectroscopic methods including FTIR, 1H NMR, and UV-Vis. The shape, morphology and size calculations have been examined using SEM, TEM, and X-ray diffraction data. The cef complexes were six-coordinate systems possessing a distorted octahedral geometry. Through the oxygen of both triazine and carboxylate moieties with the chemical formulae [Au(cef)2(Cl)(H2O)] (I), [Pt(cef)2(Cl)2] (II), and [Ru(cef)2(Cl)(H2O)] (III) the antibiotic cef acts as a bidentate ligand towards three metal ions. The newly created complexes demonstrated antibacterial activity showing efficacy in comparison to the cef sodium ligands. In vitro, antibacterial assays against specific microorganisms were evaluated to assess the antibacterial activities of the complexes. Cytotoxicity assays for cef complexes were conducted for HepG-2 and MCF-7 cell lines, representing human hepatocellular carcinoma and breast cancer, respectively. A value of 22.4 g and 26.2 g for 50% inhibitory concentration (IC50), respectively, for HepG-2 and MCF-7 were obtained for [Ru(cef)2(Cl)(H2O)] (III). KEY WORDS: Ceftriaxone sodium, Gold, Ruthenium, Platinum, Complexes, FTIR, IC50 Bull. Chem. Soc. Ethiop. 2024, 38(4), 937-948. DOI: https://dx.doi.org/10.4314/bcse.v38i4.10

Peat water purification using nanohydroxyapatite synthesized from Carbon Negative Precipitated Calcium Carbonate precursor

Peatlands covers a vast area globally and used as drinking water source in some parts of Indonesia. Peat water, commonly found in swampy areas, stands out for its striking color intensity, acidic pH levels, and its high affinity for metal binding. Developing various peat water treatment techniques can help provide clean water for local communities. This study reported the preparation of hydroxyapatite (HAp) via hydrothermal method using Carbon Negative Precipitated Calcium Carbonate (PCC) as precursor, obtained from PT. Pertamina, a leading energy company of Indonesia, for treating peat water. HAps were synthesized from precursors that were calcined at 900 °C (HAp 900) and 1000 °C (HAp 1000). Its potential as an adsorbent for peat water purification was evaluated. X-ray diffraction (XRD) revealed good crystallinity in HAp 900 and HAp 1000, with values of 82.33 % and 86.90 %, respectively. These samples also displayed nano-sized crystals, measuring 14.2 ± 0.3 nm and 23.80 ± 0.2 nm. The Ca/P molar ratios were 1.6 for HAp 900 and 1.57 for HAp 1000, which was close to the the theoretical hydroxyapatite ratio of 1.67. FTIR analysis detected the presence of carbonate groups at 1450.42 cm−1 for HAp 900 and 1426 cm−1 for HAp 1000, indicating the formation of carbonated hydroxyapatite. Scanning electron microscopy (SEM) revealed agglomerations and irregularly shaped particles in both HAp samples. Optimal conditions for peat water purification experiment, determined through UV-Vis spectrophotometry, were pH 2, 1 h contact time, and 1 g adsorbent mass for both HAp 900 and HAp 1000.

Synthesis, Characterization and in vitro Antimicrobial Activity of Organotellurium Decorated 10-Membered Tetraazamacrocyclic Complexes of Cobalt(II)

Three novel organotellurium decorated 10-membered tetraazamacrocyclic complexes of Co(II) were synthesized using template condensation of 1,1-diiodo-1-telluracyclopentane, 1,1-diodo-2-methyl-1-telluracyclopentane and 1,1-diiodo-1,1-diethyltellurium(IV) with 1,2-diaminopropane and cobalt dichloride hexahydrate in dry methanol in 2:2:1 molar ratio. The characterization of the synthesized cobalt(II) complexes was carried out using elemental analysis, spectroscopic studies (IR, proton NMR & proton decoupled carbon NMR) and molar conductance measurements. The results of these studies suggested that the complexes may be formulated as [CoLCl2] where L = {C4H8Te-(NHCH2CH(CH3)NH)}2, {C4H7(CH3)Te(NHCH2CH(CH3)NH)}2 and {(C2H5)2Te(NHCH2CH(CH3)NH)}2. The synthesized complexes were also screened for antimicrobial activity using broth microdilution and agar disc diffusion methods.

Application of experimental design in the synthesis of 1-butanol from ethanol on mixed oxide catalysts at different mg/al molar ratios

1-Butanol, primarily sourced from petroleum, is currently being considered as a viable alternative to gasoline. Various pathways for synthesizing 1-butanol from renewable raw materials have been explored, with a particular focus on the Guerbet reactions. This study aimed to investigate the synthesis of 1-butanol from ethanol using Mg/Al mixed oxides derived from layered double hydroxides with Mg/Al molar ratios of 3:1, 5:1, 8:1, and 10:1. The catalysts were analyzed through X-ray diffraction, X-ray fluorescence, N2 adsorption, scanning electron microscope and energy-dispersive X-ray spectroscopy. Catalytic reaction tests were performed according to a Central Composite Rotatable Design (CCRD) with three replicates at the central point (CP). Among the catalysts tested at CP, the mixed oxides with Mg/Al molar ratios of 3:1 and 5:1 exhibited the most promising results, displaying similar ethanol conversion, and 1-butanol selectivity. This similarity underscores their well-balanced combination of both acidic and basic sites. However, further assessment through a deactivation test revealed that the mixed oxides with Mg/Al molar ratio of 5:1 held the most potential for long-term 1-butanol synthesis from ethanol, thanks to its superior stability and sustained activity. Using this catalyst, other reaction tests were carried out following the CCRD, varying N2 feed flowrate, ethanol molar content in feed flowrate, and temperature. The results indicated that an increase in ethanol conversion directly correlated with higher temperatures, while the 1-butanol selectivity depended on both the N2 feed flowrate, ethanol molar content in feed flowrate, highlighting the importance of a well-balanced combination of both acidic and basic sites.

A Vortex-Assisted Deep Eutectic Solvent for Parabens Extraction in Cosmetic Samples Coupled with High Performance Liquid Chromatography

Parabens, commonly used preservatives in food, cosmetics, and pharmaceutical items, inhibit harmful germ growth. Deep Eutectic Solvents (DES) are intriguing for analyte extraction due to superior properties formed through hydrogen bond acceptors and donor interactions. However, the studies on the optimal DES-based extraction conditions for paraben-containing cosmetics and the accuracy of 'paraben-free' labels are limited. The most effective DES (DL-Menthol and decanoic acid, 1:2 molar ratio) was applied to cosmetic samples after heating at 80 °C following optimization parameters. FTIR study confirmed hydrogen bonds in DES samples. Both paraben-containing and paraben-free samples showed methyl, ethyl, and propyl paraben peaks from the HPLC analysis. Cosmetic sample paraben concentrations ranged from 0.53 mg/L to 26.08 mg/L (non-spiked). LOD and LOQ were 0.24 mg/L-1.62 mg/L, 0.73 mg/L, and 4.8 mg/L, respectively. Goals were met by establishing a paraben extraction method using DES and investigating paraben quantities in cosmetics.

Effect of the Photoreduction Process on the Self-Cleaning and Antibacterial Activity of Au-Doped TiO2 Colloids on Cotton Fabric.

This study aims at understanding the effect of the photoreduction process during the synthesis of gold (Au)-doped TiO2 colloids on the conferred functionalities on cotton fabrics. TiO2/Au and TiO2/Au/SiO2 colloids were synthesized through the sol-gel method with and without undergoing the photoreduction step based on different molar ratios of Au:Ti (0.001 and 0.01) and TiO2/SiO2 (1:1 and 1:2.3). The colloids were applied to cotton fabrics, and the obtained photocatalytic self-cleaning, wet photocatalytic activity, UV protection, and antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria were investigated. The obtained results demonstrated that the photoreduction of Au weakened the self-cleaning effect and reduced the photocatalytic activity of coated fabrics. Also, an excess amount of Au deteriorated the photocatalytic activity under both UV and visible light. The most efficient self-cleaning effect was obtained on fabrics coated with a ternary TiO2/Au/SiO2 colloid containing ionic Au, where it decomposed coffee and red-wine stains after 3 h of illumination. Adding silica (SiO2) made the fabrics superhydrophilic and led to greater methylene blue (MB) dye adsorption, a faster dye degradation pace, and more efficient stain removal. Moreover, the photoreduction process affected the size of Au nanoparticles (NPs), weakened the antibacterial activity of fabrics against both types of tested bacteria, and modestly increased the UV protection. In general, the photoactivity of Au-doped colloids was influenced by the synthesis method, the ionic and metallic states of the Au dopant, the concentration of the Au dopant, and the presence and concentration of silica.

Synthesis of weak cation exchange/C18 bifunctional magnetic polymers for pretreatment and determination of glufosinate and its two metabolites in plasma samples

This study focuses on the purification and detection of glufosinate (GLUF) and its metabolites N-acetyl GLUF and MPP in plasma samples. A Dikma Polyamino HILIC column was used for the effective retention and separation of GLUF and its metabolites, and the innovative addition of a low concentration of ammonium fluoride solution to the mobile phase effectively improved the detection sensitivity of the target analytes. Monodisperse core-shell weak cation exchange (WCX)/C18 bifunctional magnetic polymer composites (Fe3O4@WCX/C18) were prepared in a controllable manner, and their morphology and composition were fully characterized. The Fe3O4@WCX/C18 microspheres were used as a magnetic solid-phase extraction (MSPE) adsorbent for the sample purification and detection of GLUF and its metabolites in plasma samples combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS). The purification conditions of Fe3O4@WCX/C18 microspheres for GLUF and its metabolites in spiked plasma samples were optimized to achieve the best MSPE efficiency. The purification mechanisms of the target analytes in plasma samples include electrostatic attraction and hydrophobic interactions. Furthermore, the effect of the molar ratio of the two functional monomers 4-VBA and 1-octadecene in the adsorbent was optimized and it shows that the bifunctional components WCX/C18 have a synergistic effect on the determination of GLUF and its metabolites in plasma samples. In addition, the present study compared the purification performance of the Fe3O4@WCX/C18 microsphere-based MSPE method with that of the commercial Oasis WCX SPE method, and the results showed that the Fe3O4@WCX/C18 microsphere-based MSPE method established in this work had a stronger ability to remove matrix interferences. Under optimal purification conditions, the recoveries of GLUF and its metabolites in plasma were 87.6–111 % with relative standard deviations (RSDs) ranging from 0.2 % to 4.8 %. The limits of detection (LODs, S/N≥3) and limits of quantification (LOQs, S/N≥10) were 0.10–0.18 μg/L and 0.30–0.54 μg/L, respectively. The MSPE-LC-MS/MS method developed in this study is fast, simple, accurate and sensitive and can be used to confirm GLUF intoxication based not only on the detection of the GLUF prototype but also on the detection of its two metabolites.

Innovative deep decontamination of radioactive solid surfaces using microemulsions of deep eutectic solvents in supercritical carbon dioxide

Radioactive solid wastes resulting from the application of nuclear energy pose a risk to the environment, yet traditional decontamination methods generate many secondary wastes. Thus, sustainability-driven innovations are receiving increasing attention to achieve eco-friendly decontamination methods characterized by minimizing secondary waste generation. Here, we proposed a sustainable and pioneering approach to decontaminate radioactive solid wastes using microemulsions of deep eutectic solvents (DESs) in supercritical carbon dioxide (SC-CO2). We also determined the optimal ratios of the additives as follows: prepared DESs with a molar ratio of choline chloride (ChCl) to p-toluenesulfonic acid monohydrate (ptsa) of 1:2, and nonyl phenol polyoxyethylene ether (NP-10) to ChCl:ptsa DESs in a molar ratio of 0.8. Remarkably, after optimization of the decontamination process in terms of pressure, temperature and cleaning time, the radioactivity on the sample surface can be reduced to a level that is reusable in the nuclear field. Detailed analyses provided insights into the intermolecular interactions within the DESs. And the decontamination mechanisms involved the spontaneous evolution of microemulsions with ChCl:ptsa as the core to facilitate the solvation and removal of radioactive contaminants. Additionally, repeated cleaning was proved to be effective for ultra-deep decontamination, with the radioactivity on the sample surface reaching a clearance level and a decontamination efficiency of 99.8%. The DESs-in-CO2 systems successfully decontaminated various materials and simulated radionuclides, even real radioactive metal wastes from the nuclear industry. It was notable that the DESs-in-CO2 systems achieved decontamination efficiencies of more than 95.0% for radioactive contaminants on these solid surfaces. Overall, this innovative approach provided a green alternative to conventional radioactive solids decontamination, meeting the need for sustainable development of nuclear energy.

Highly sensitive detection of copper in aqueous media using a fluorescent probe developed from isophthaldehyde and (E)-1-(hydrazonomethyl) naphthlen-2-ol

A highly selective Schiff base PMB3 with AIEE activity was synthesized and characterized for detecting Cu2+ in aqueous media. The PMB3 aggregates exhibit a green fluorescence in the DMF-water mixed solvent, demonstrating a switch-off response specifically to Cu2+ ions over various other biologically significant metal ions. The quenching of fluorescence in PMB3 aggregates is likely attributed to the disassembly caused by the chelation of the imine-N atom and phenolic -O atom of PMB3 aggregates with Cu2+ ions. The molar ratio of the complex formed as per Job’s plot method was 1:1 between PMB3 and Cu2+. The fluorescence lifetime measurements confirmed the involvement of the dynamic quenching process in the reaction cycle. The analysis of the Stern-Volmer plot divulged a quenching constant of 3.75×1015 M−1. Remarkably, the limit of detection was determined to be 16.08×10−15 M (16.08fM), demonstrating a sensitivity far exceeding the permissible limit set by the World Health Organization.

Mechanical insights into desulfurization by peroxymonosulfate oxidation via a non-reactive oxygen species pathway

Air pollution by sulfur dioxide (SO2) remains a pressing concern for both the environment and human health. Desulfurization enhanced by persulfate based advanced oxidation processes (PS-AOPs) has been proven to be a feasible method. However, the inherent contradiction between the rapid diffusion mass transfer of SO2 in the “gas-liquid-gas” phase and the limited lifespan of reactive oxygen species (ROS) can not be ignored. Excessive investment in PS is required to sustainably generate ROS to achieve continuous desulfurization performance, which may lead to excessive PS consumption. To address this issue, whether PS can achieve the oxidation absorption of SO2 via a non-reactive oxygen species pathway was investigated. Experimental and computational results demonstrated that peroxymonosulfate (PMS) instead of peroxydisulfate (PDS) had a great SO2 removal performance, the utilization of PS could be effectively achieved by maintaining a 1:1 molar ratio of PMS and removed SO2. The presence of HOO bonds in the PMS introduced a partial positive charge to the oxygen atom, making the PMS polar and more susceptible to be attacked by the nucleophile HSO3-. So SO2 underwent a series of processes including dissolution, dissociation, one-oxygen atom transfer, and ionization before ultimately being converted into SO42- ions, effectively achieving its removal from flue gas. This study may presents a novel approach for achieving high-efficiency flue gas desulfurization.