Construction of novel binary metal oxides: Copper oxide–tin oxide nanoparticles regulated for selective and nanomolar level electrochemical detection of anti-psychotic drug

Synthesis of anisotropic silica nanoparticles by organic amine with diverse structures

Herein, we synthesized anisotropic silica nanoparticles (AISNPs) with organic amines with different structures. Monoamines and diamines with distance between amine groups shorter thanca.4 Å have been observed to facilitate the formation of isotropic silica nanoparticles (ISNPs). AISNPs were synthesized with diamines with distance between amine groups longer thanca.4 Å and linear structures of triamines. Non-linear structures with amine groups positioned in a triangular configuration and the cage-like structure of tetra-amines directed the formation of ISNPs. It has been speculated that the formation of AISNPs would be due to the spherical primary particles connecting by organic amines with two or more amine groups with distances between them longer thanca.4 Å. On the contrary, the formation of ISNPs would be attributed to the adsorption of two amine groups on the same primary particles, or to steric hindrance that prevent their connection.

A sensitive electrochemical sensor based on CoWO4/multi-walled carbon nanotubes for the selective determination of chlorpromazine hydrochloride

In this work, a novel electrochemical sensor based on cobalt tungstate/multi-walled carbon nanotube (CoWO4/MWCNT) nanocomposites has been used to detect chlorpromazine hydrochloride (CPZ). The CoWO4/MWCNT nanocomposite was obtained by solvothermal technology and ultrasonic method and analyzed using different characterization techniques such as scanning electron microscopy (SEM), X-ray diffractometry (XRD), energy-dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The electrochemical behavior of CoWO4/MWCNT/GCE was explored using cyclic voltammetry (CV). Electrochemical experiments confirm that CoWO4/MWCNT/GCE exhibits excellent electrocatalytic activity towards CPZ with good selectivity, reproducibility and stability. The linear dynamic range of CPZ was observed to be 1-2000 μM with a detection limit of 0.33 μM. Moreover, the actual sample was analyzed using lake water with satisfactory results, portraying the sensor as a potential candidate for the detection of CPZ.

Green Engineered CuO/SnO2/HNT Composites: Illuminating the Photocatalytic Path for Organic Pollutant Remediation and Zebrafish Embryo Toxicity Evaluation

Photocatalysis stands out as a promising technique for treating organic contaminants, yet the quest for visible light active composite materials, crafted through cost-effective, eco-friendly, and uncomplicated processes, poses formidable challenges. Here, we introduce a successful endeavor, the synthesis of a CuO/SnO2 (CS) composite via a microwave method, employing Carissa edulis fruit extract as a reducing as well as capping agent. Various loadings of CS-HNT composites were prepared by ultrasonically incorporating CS onto nanotubular halloysite (HNT) clay. Employing a suite of types of characterization, including XRD, XPS, FT-IR, FE-SEM, HR-TEM, ζ potential, UV-vis-DRS, TGA, BET, and EIS, we meticulously explored the morphology, structure, stability, surface area, electrochemical, and optical properties of the developed CS-HNT composites. HR-TEM observations unveiled the formation of a heterojunction between cubic CuO and spherical SnO2 on the HNT clay surface. Optical and EIS analysis highlighted that the 20CS-HNT composite displayed significant absorption in the visible region, efficient electron-hole pair separation, and enhanced interfacial charge transport relative to other loadings. Photocatalytic evaluations and optimization studies revealed that the 20CS-HNT photocatalyst achieved notable removal efficiencies, eliminating 85% of Congo red (CR) and 80% of tetracycline (TC) within 90 min and 74% of ATZ in 3 h under visible light conditions. Scavenging investigations, the fluorescence probe method, and a NBT transformation study underscored the pivotal roles of hydroxyl and superoxide radicals in pollutant removal. The reusability trials highlighted the exceptional stability and recyclability of the photocatalyst, even after five cycles. In addition, zebrafish embryo toxicity tests revealed improved survival and hatching rates in photocatalyst-treated samples compared to those of controls. Moderate toxicity was observed in treated TC, while the treated CR sample showed non-lethal toxicity. In essence, this study unveils a straightforward and efficacious approach for developing photocatalysts for large-scale wastewater treatment. Furthermore, it proposes the adoption of safe clay-based bimetal oxide photocatalysts in diverse environmental applications.

An innovative experimental and mathematical approach in electrochemical sensing for mapping a drug sensor landscape

Our study delves into the examination of an electrochemical sensor through both experimentation and mathematical analysis. The sensor demonstrates the ability to identify a specific antipsychotic medication, namely Chlorpromazine Hydrochloride (CPH), even at incredibly low concentrations, reaching the picomolar level. The identification process relies on the utilization of a Glassy Carbon Electrode (GCE) that has been modified with a ceria-doped zirconia (CeO2/ZrO2) nanocomposite. The nanocomposite was synthesized using the co-precipitation technique and extensively characterized through various analytical methods. It is crucial to detect the presence of CPH as an overdose can result in hyperactivity and severe bipolar disorders among both children and adults. The average size of the nanocomposite was estimated to be 10 nm. The electrode surface area after CeO2/ZrO2 modification of the GCE was found to be 0.059 cm2, which was significantly higher than the electrode surface area of the bare GCE (0.0307 cm2). The limit of detection and limit of quantification for CPH were calculated to be 99.3 pM and 3.010 nM, respectively, with the linear dynamic range of CPH detection found to be between 0.10 and 1.90 μM. The modified sensor electrode was tested on human urine samples with good recoveries and exhibited high selectivity, repeatability, reproducibility, and long-term stability. The experimental voltammograms and the simulated stochastic voltammograms exhibited a fair amount of agreement. Examination of the experimental findings alongside analytical and numerical solutions enables a comprehensive analysis of the factors influencing the outcome of electrochemical measurements. The precise findings can be leveraged for the development of efficient sensing devices for medical diagnostics and environmental monitoring.

Binary metal oxide (NiO/SnO2) composite with electrochemical bifunction: Detection of neuro transmitting drug and catalysis for hydrogen evolution reaction

The synergetic effect between dual oxides in binary metal oxides (BMO) makes them promising electrode materials for the detection of toxic chemicals, and biological compounds. In addition, the interaction between the cations and anions of diverse metals in BMO tends to create more oxygen vacancies which are beneficial for energy storage devices. However, specifically targeted synthesis of BMO is still arduous. In this work, we prepared a nickel oxide/tin oxide composite (NiO/SnO2) through a simple solvothermal technique. The crystallinity, specific surface area, and morphology were fully characterized. The synthesized BMO is used as a bifunctional electrocatalyst for the electrochemical detection of dopamine (DPA) and for the hydrogen evolution reaction (HER). As expected, the active metals in the NiO/SnO2 composite afforded a higher redox current at a reduced redox potential with a nanomolar level detection limit (4 nm) and excellent selectivity. Moreover, a better recovery rate is achieved in the real-time detection of DPA in human urine and DPA injection solution. Compared to other metal oxides, NiO/SnO2 composite afforded lower overpotential (157 mV @10 mA cm-2), Tafel slope (155 mV dec-1), and long-term durability, with a minimum retention rate. These studies conclude that NiO/SnO2 composite can act as a suitable electrode modifier for electrochemical sensing and the HER.

An electrochemical chlorpromazine sensor based on a gold-copper bimetallic synergetic molecularly imprinted interface on an acupuncture needle electrode

Chlorpromazine (CPZ) is a medicine for nervous system disorders. Measuring CPZ in vivo can assist doctors in evaluating patients' blood drug concentration and monitoring drug metabolism. Therefore, an accurate in vivo detection of CPZ is crucial. In recent years, the acupuncture needle, traditionally used in Chinese medicine, has emerged as a potential electrode in the field of electrochemistry, with promising applications for in vivo detection. In this study, Au/Cu nanoparticles were electrodeposited onto an acupuncture needle electrode (ANE) to improve electrical conductivity and provide an electro-catalytic surface. Subsequently, 3-aminophenylboronic acid and CPZ were attracted to each other through intermolecular forces; at the same time, the interaction force of Au-S between CPZ and the AuNPs made the polymer layer grow around the CPZ molecules on the modified electrode surface. The imprinted nanocavities showed highly selective and sensitive detection performance for CPZ after elution. Inside the recognizable site and microenvironment of the cavities, the captured CPZ molecule provided a suitable configuration for the fluent electron transfer of the electroactive group within a short range from the Au/Cu bimetal. Under ideal conditions, the MIP/Au/Cu/ANE exhibited two good linear ranges of 0.1-100 μM and 100-1000 μM with a detection limit of 0.07 μM. Moreover, the sensors showed great selectivity, good stability and excellent repeatability, making them suitable for CPZ detection in human serum. This provides a novel idea for real-time and in vivo CPZ detection.

Zinc Oxide/Phosphorus-Doped Carbon Nitride Composite as Potential Scaffold for Electrochemical Detection of Nitrofurantoin

Herein, we present an electrocatalyst constructed by zinc oxide hexagonal prisms/phosphorus-doped carbon nitride wrinkles (ZnO HPs/P-CN) prepared via a facile sonochemical method towards the detection of nitrofurantoin (NF). The ZnO HPs/P-CN-sensing platform showed amplified response and low-peak potential compared with other electrodes. The exceptional electrochemical performance could be credited to ideal architecture, rapid electron/charge transfer, good conductivity, and abundant active sites in the ZnO HPs/P-CN composite. Resulting from these merits, the ZnO HPs/P-CN-modified electrode delivered rapid response (2 s), a low detection limit (2 nM), good linear range (0.01-111 µM), high sensitivity (4.62 µA µM^-1 cm²), better selectivity, decent stability (±97.6%), and reproducibility towards electrochemical detection of NF. We further demonstrated the feasibility of the proposed ZnO HPs/P-CN sensor for detecting NF in samples of water and human urine. All the above features make our proposed ZnO HPs/P-CN sensor a most promising probe for detecting NF in natural samples.

Barium titanate nanoparticle-based disposable sensor for nanomolar level detection of the haematotoxic pollutant quinol in aquatic systems

Barium titanate nanoparticles synthesized by a simple co-precipitation method and applied for the electrochemical detection of quinol.