Novel potentiometric sensor for the determination of Cd2+ based on a new nano-composite

A novel ion selective carbon paste electrode for Cd²⁺ ions based on 2,2′-thio-bis[4-methyl(2-amino phenoxy) phenyl ether] (TBMAPPE) as an ionophore was prepared. The carbon paste was made based on a new nano-composite including multi-walled carbon nanotubes (MWCNTs), nanosilica and room-temperature ionic liquid, 1-Butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF₆). The constructed nano-composite electrode showed better sensitivity, selectivity, response time, response stability and lifetime in comparison with typical Cd²⁺ carbon paste sensor for the successful determination of Cd²⁺ ions in water and in waste water samples. The best performance for nano-composite sensor was obtained with an electrode composition of 18% TBMAPPE, 20% BMIM-PF₆, 48% graphite powder, 10% MWCNT and 4% nanosilica. The new electrode exhibited a Nernstian response (29.95?±?0.10?mV?decade^?1) toward Cd²⁺ ions in the range of 3.0?×?10^?8 to 1.0?×?10^?1?mol?L^?1 with a detection limit of 7.5?×?10^?9?mol?L^?1. The potentiometric response of prepared sensor was independent of the pH of test solution in the pH range 3.0 to 5.5. It had a quick response with a response time of about 6?s. The proposed electrode showed fairly good selectivity over some alkali, alkaline earth, transition and heavy metal ions.     

Chemoselective synthesis of xanthenes and tetraketones in a choline chloride-based deep eutectic solvent

A chemoselective synthesis of tetraketone and xanthene derivatives, by means of tandem Knoevenagel condensation and Michael addition in choline chloride-based deep eutectic solvents (DESs), is presented. The reaction of readily available aldehydes and active methylene compounds in malonic acid- and ZnCl₂-based DES gives various xanthenes derivatives with good to excellent yields under mild reaction conditions. On the other hand, tetraketones were synthesized in almost quantitative yields by simple condensation of an aldehyde and active methylene compounds in milder deep eutectic solvents of urea and SnCl₂. In addition, the reaction of other types of choline chloride-based DES leads to a mixture of tetraketone and xanthene.     

A Targeted Review of Current Progress,Challenges and Future Perspective of g-C3N4 based Hybrid Photocatalyst Toward Multidimensional Applications

The increasing demand for searching highly efficient and robust technologies in the context of sustainable energy production totally rely onto the cost-effective energy efficient production technologies. Solar power technology in this regard will perceived to be extensively employed in a variety of ways in the future ahead, in terms of the combustion of petroleum-based pollutants, CO₂ reduction, heterogeneous photocatalysis, as well as the formation of unlimited and sustainable hydrogen gas production. Semiconductor-based photocatalysis is regarded as potentially sustainable solution in this context. g-C₃N₄ is classified as non-metallic semiconductor to overcome this energy demand and enviromental challenges, because of its superior electronic configuration, which has a median band energy of around 2.7 eV, strong photocatalytic stability, and higher light performance. The photocatalytic performance of g-C₃N₄ is perceived to be inadequate, owing to its small surface area along with high rate of charge recombination. However, various synthetic strategies were applied in order to incorporate g-C₃N₄ with different guest materials to increase photocatalytic performance. After these fabrication approaches, the photocatalytic activity was enhanced owing to generation of photoinduced electrons and holes, by improving light absorption ability, and boosting surface area, which provides more space for photocatalytic reaction. In this review, various metals, non-metals, metals oxide, sulfides, and ferrites have been integrated with g-C₃N₄ to form mono, bimetallic, heterojunction, Z-scheme, and S-scheme-based materials for boosting performance. Also, different varieties of g-C₃N₄ were utilized for different aspects of photocatalytic application i. e., water reduction, water oxidation, CO₂ reduction, and photodegradation of dye pollutants, etc. As a consequence, we have assembled a summary of the latest g-C₃N₄ based materials, their uses in solar energy adaption, and proper management of the environment. This research will further well explain the detail of the mechanism of all these photocatalytic processes for the next steps, as well as the age number of new insights in order to overcome the current challenges.     

Polycarbonate-coated magnetic nanoparticles for the extraction of imipramine and its primary metabolite from urine

This study introduces a reliable and inexpensive magnetic dispersive solid phase extraction to extract imipramine and its primary metabolite (desipramine) from urine samples. To accomplish this aim, Fe₃O₄ magnetic nanoparticles were synthesized by sonication, subsequently, polycarbonate was precipitated gradually onto the surface of them to form the adsorbent. Extraction recoveries of 85% and 76%, enrichment factors of 57 and 51, limits of detection of 2.5 and 2.8 μg/L, and limits of quantification of 8.3 and 9.3 μg/L were obtained for imipramine and desipramine under the optimal conditions, respectively. In addition, relative standard deviations for intra- (n = 6) and inter-day (n = 5) precisions at two concentrations (50 and 100 μg/L of each analyte) were less than or equal to 4%. Short extraction time, good repeatability, high enrichment factors, and simplicity are the main advantages of the proposed method.     

Fast Quantitation of Target Analytes in Small Volumes of Complex Samples by Matrix‐Compatible Solid‐Phase Microextraction Devices

Herein we report the development of solid‐phase microextraction (SPME) devices designed to perform fast extraction/enrichment of target analytes present in small volumes of complex matrices (i.e. V≤10 μL). Micro‐sampling was performed with the use of etched metal tips coated with a thin layer of biocompatible nano‐structured polypyrrole (PPy), or by using coated blade spray (CBS) devices. These devices can be coupled either to liquid chromatography (LC), or directly to mass spectrometry (MS) via dedicated interfaces. The reported results demonstrated that the whole analytical procedure can be carried out within a few minutes with high sensitivity and quantitation precision, and can be used to sample from various biological matrices such as blood, urine, or Allium cepa L single‐cells.     

Thiazolidinedione Derivatives: In Silico,In Vitro,In Vivo,Antioxidant and Anti-Diabetic Evaluation

This work aimed to synthesize a new antihyperglycemic thiazolidinedione based on the spectral data. The DFT\B3LYP\6-311G** level of theory was used to investigate the frontier molecular orbitals (FMOs), chemical reactivity and map the molecular electrostatic potentials (MEPs) to explain how the synthesized compounds interacted with the receptor. The molecular docking simulations into the active sites of PPAR-γ and α-amylase were performed. The in vitro potency of these compounds via α-amylase and radical scavenging were evaluated. The data revealed that compounds (4–6) have higher potency than the reference drugs. The anti-diabetic and anti-hyperlipidemic activities for thiazolidine-2,4-dione have been investigated in vivo using the alloxan-induced diabetic rat model along with the 30 days of treatment protocol. The investigated compounds didn’t show obvious reduction of blood glucose during pre-treatments compared to diabetic control, while after 30 days of treatments, the blood glucose level was lower than that of the diabetic control. Compounds (4–7) were able to regulate hyperlipidemia levels (cholesterol, triglyceride, high-density lipoproteins and low- and very-low-density lipoproteins) to nearly normal value at the 30th day.     

Retrievable magnetic copper ferrite nanoparticles: an efficient catalyst for air oxidative cyclization of bisnaphthols

Herein, a green and efficient heterogeneous and photocatalytic system for the oxidation of bisnaphthols in acetonitrile under light-emitting diode will be presented. In this reaction, aerial oxygen and H₂O₂ have been used as oxidant in the presence of copper ferrite nanoparticles and N-hydroxyphthalimide as an organic co-catalyst. Copper ferrite nanoparticles were magnetically separated, the efficiency of which remained nearly unchanged up to five cycles. Magnetic copper ferrite nanoparticles were synthesized by sol–gel method and characterized by XRD, FT-IR, SEM, TEM, VSM and DRS analysis. In this project, both sets of diastereomers were formed.

Graphical abstract

Catalytic system for the oxidation of bisnaphthols.

     

Effect of CH3NH3I/CH3NH3Br precursors on the structural and surface morphology properties of the electrodeposited methylammonium lead–mixed halide perovskite films

Journal of Solid State Electrochemistry - Organometallic halide perovskites have been arisen as a class of multi-purpose materials with exciting applications in optoelectronic devices such as solar...     

Nucleophilic substitutions at the pyridine ring: Kinetics of the reaction of 2-chloro-3-nitro and 2-chloro-5-nitropyridines with piperidine and morpholine in methanol and benzene

The kinetics of the reactions of 2-chloro-3-nitropyridine (ortho-like) and 5-nitro (para-like) isomer with morpholine and piperidine were studied in methanol and benzene at several amine concentrations and temperatures in the range 25–45°C. The data show that k/k ratios are less than unity in methanol. The steric hindrance in the transition state of the 3-nitro (ortho-like) isomer retards o-substitution while the stability of p-quinonoid structure of the 5-nitro (para-like) isomer favors p-substitution. In benzene, the k_3-NO2/k_5-NO2 ratios are greater than unity. The hydrogen bonding formation between the ammonium hydrogen and the ortho-nitro group in the transition state of 3-nitro isomer favors the o-substitution. © 1997 John Wiley & Sons, Inc.     

Chemical Composition,Antioxidant and Cytoprotective Potentials of Carica papaya Leaf Extracts: A Comparison of Supercritical Fluid and Conventional Extraction Methods

The leaves of Carica papaya (CP) are rich in natural antioxidants. Carica papaya has traditionally been used to treat various ailments, including skin diseases. This study aims to decipher the antioxidant effects and phytochemical content of different CP leaf extracts (CPEs) obtained using supercritical carbon dioxide (scCO₂) and conventional extraction methods. The antioxidant activities of CPEs were evaluated by cell-free (1,1-diphenyl-2-picryl-hydrazyl (DPPH) and ferric-reduced antioxidative power (FRAP)) and cell-based (H₂O₂) assay. Both C. papaya leaf scCO₂ extract with 5% ethanol (CPSCE) and C. papaya leaf scCO₂ extract (CPSC) exhibited stronger DPPH radical scavenging activity than conventional extracts. In the FRAP assay, two hydrophilic extracts (C. papaya leaf ethanol extract (CPEE) and C. papaya freeze-dried leaf juice (CPFD)) showed relatively stronger reducing power compared to lipophilic extracts. Cell-based assays showed that CPFD significantly protected skin fibroblasts from H₂O₂-induced oxidative stress in both pre-and post-treatment. CPEE protected skin fibroblasts from oxidative stress in a dose-dependent manner while CPSCE significantly triggered the fibroblast recovery after treatment with H₂O₂. GC-MS analysis indicated that CPSCE had the highest α-tocopherol and squalene contents. By contrast, both CP hydrophilic extracts (CPEE and CPFD) had a higher total phenolic content (TPC) and rutin content than the lipophilic extracts. Overall, CPEs extracted using green and conventional extraction methods showed antioxidative potential in both cell-based and cell-free assays due to their lipophilic and hydrophilic antioxidants, respectively.