Differential pulse striping voltammetric determination of molluscicide niclosamide using three different carbon nanomaterials modified electrodes

Design and fabrication of electrochemical sensor based on NiO/Ni@C-Fe3O4/CeO2 for the determination of niclosamide

In this study, we aimed to enhance and accelerate the electrochemical properties of a glassy carbon-based voltammetric sensor electrode. This was achieved through the modification of the electrode using a nanocomposite derived from a metal-organic framework, which was embedded onto a substrate consisting of metal oxide nanoparticles. The final product was an electrocatalyst denoted as NiO/Ni@C-Fe3O4/CeO2, tailored for the detection of the drug niclosamide. Several techniques, including FT-IR, XRD, XPS, FE-SEM, TEM, and EDS, were employed to characterize the structure and morphology of this newly formed electroactive catalyst. Subsequently, the efficiency of this electrocatalyst was evaluated using cyclic voltammetry and electrochemical impedance spectroscopy techniques. Differential pulse voltammetry was also utilized to achieve heightened sensitivity and selectivity. A comprehensive exploration of key factors such as the catalyst quantity, optimal instrumental parameters, scan rate influence, and pH effect was undertaken, revealing a well-regulated reaction process. Furthermore, the sensor's analytical performance parameters were determined. This included establishing the linear detection range for the target compound within a specified concentration interval of 2.92 nM to 4.97 μM. The detection limit of 0.91 nM, repeatability of 3.1%, and reproducibility of 4.8% of the sensor were calculated, leading to the observation of favorable stability characteristics. Conclusively, the developed electrochemical sensor was successfully employed for the quantification of niclosamide in urine samples and niclosamide tablets. This application highlighted not only the sensor's high selectivity but also the satisfactory and accurate outcomes obtained from these measurements.

Techniques for analytical estimation of COVID-19 clinical candidate, niclosamide in pharmaceutical and biomedical samples

Niclosamide is a well-known broad-spectrum antiparasitic drug used for human as well as veterinary tapeworm infections. Recently, it attracted attention as an antiviral agent for treating coronavirus disease 2019. It is administered orally in humans to treat tapeworm infections. Furthermore, it is a registered pesticide and molluscicide to control infections in the aquaculture industry. Its chronic environmental exposure has potential toxicities when such contaminated seafood is consumed. Therefore, monitoring its residual concentration in food products (seafood, water, water waste, etc.) and pharmaceuticals (active pharmaceutical ingredients, bulk drugs, and formulations) is imperative. The present review critically investigates the sophisticated techniques employed for analyzing niclosamide, its degradation products, and metabolites in various samples and matrices. The future scope for green analytical methods, green sample extraction and preparation is also deliberated.

Amplified electrochemical determination of niclosamide in food based on carbon nanohorn@MWCNT composite

In this work, carbon nanohorn (CNH)-decorated multi-walled carbon nanotube (MWCNT) (CNH@MWCNT) composite was prepared and used to modify glass carbon electrode (GCE) as sensitive electrochemical sensor for niclosamide (NA) determination. Herein, the decoration of CNHs induces higher dispersibility for MWCNTs, and endows the composite with better conductivity, larger surface area, and higher catalytic activity, which leads to significantly enhanced electrochemical behavior toward NA oxidation. The parameters such as mass ratios of CNHs and MWCHTs, the amount of composite materials, the accumulation time, and the solution pH are systematically optimized. Under optimized conditions, the developed electrochemical sensor exhibits a low detection limit of 2.0 nM with a wide linear range of 7.0 nM-10.0 µM and high anti-interference ability. In addition, the sensor displays good stability, repeatability, and reproducibility. The feasibility of the assay was verified by testing NA in brown rice and rice field water samples.

Nitrogen, phosphorus co-doped hollow porous carbon microspheres as an oxidase-like electrochemical sensor for baicalin

The extraordinary properties and unique structure of porous carbon has rapidly turned into a new favorite in the development and application of high-performance electrocatalytic sensor. Nitrogen, phosphorus co-doped hollow porous...

Intelligent analysis of maleic hydrazide using a simple electrochemical sensor coupled with machine learning

A simple electrochemical sensing platform based on a low-cost disposable laser-induced porous graphene (LIPG) flexible electrode for the intelligent analysis of maleic hydrazide (MH) in potatoes and peanuts coupled with machine learning (ML) was successfully designed. The LIPG electrode was patterned by a simple one-step laser-induced procedure on commercial polyimide film using a computer-controlled direct laser writing micromachining system and displayed excellent flexibility, 3D porous structure, large specific surface area, and preferable conductivity. A data partitioning technique was proposed for the optimal MH concentration ranges by selecting the size of datasets, including the size of the training set and the size of the test set combined with the performance metrics of ML models. Different algorithms such as artificial neural networks (ANN), random forest (RF), and least squares support vector machine (LS-SVM) were selected to build the ML models. Three ML models were evaluated, and the LS-SVM model displayed unique superiority. Both the recoveries and RSD of practical application were further measured to assess the feasibility of the selected LS-SVM model. This will have important theoretical and practical significance for the intelligent analysis of harmful residuals in agro-product safety using an electrochemical sensing platform.

Three-dimensional hierarchical porous carbon coupled with chitosan based electrochemical sensor for sensitive determination of niclosamide

Herein, a simple, low-cost, environment-friendly strategy was proposed to prepare the composite of three-dimensional hierarchical porous carbon and chitosan, which was applied to modify the glass carbon electrode to fabricate an electrochemical sensor for the determination of niclosamide. The three-dimensional porous carbon with interconnected conductive network, high surface area, and self-generated oxygen-containing functional groups was prepared by salt-templating method with glucose as carbon source and eutectic mixture of LiBr/KBr as both activating and pore-forming agent. During the subsequent ultrasonic process, chitosan with excellent filming property, strong adsorption ability, and good dispersibility was successfully decorated on the obtained porous carbon to further enhance the determination performance of niclosamide. Benefitting from the multi-functional integration of three-dimensional hierarchical porous carbon and chitosan, the fabricated sensor presented a low limit of detection (6.7 nM) in the linear concentration range from 0.01 to 10 µM. Moreover, the fabricated sensor could show good repeatability, reproducibility, stability, and selectivity. Most important, the decent practicability for the detection of niclosamide was obtained in different food samples with low relative standard deviation and satisfactory recoveries. This work provides a very valuable reference for the sensitive determination of niclosamide in food samples.

Facile synthesis of Vulcan XC-72 nanoparticles-decorated halloysite nanotubes for the highly sensitive electrochemical determination of niclosamide

We report a scalable and controllable ultrasound-assisted strategy for the preparation of Vulcan XC-72 nanoparticles-decorated halloysite nanotubes (HNTs@VXC-72), which was applied to modify glassy carbon electrode (GCE) for the highly sensitive electrochemical determination of niclosamide (NA). For the HNTs@VXC-72 nanocomposite, VXC-72 nanoparticles with excellent electrical conductivity and good dispersing property contributed to the formation of the interconnected conductive network; HNTs possessed good adsorption performance and promoted the electrochemical redox reaction. The research results showed that the combination of VXC-72 nanoparticles and HNTs produced the effect of synergistic enhancement. The HNTs@VXC-72/GCE sensor could show a relatively low detection limit of 3.28 nM in the great linear NA concentration range of 0.01-1 µM. When used for the NA determination in food samples, the HNTs@VXC-72/GCE sensor exhibited good practical feasibility with low RSD and acceptable recoveries, which provided a promising NA determination approach to ensure food safety.

Simultaneous Determination of Streptomycin and Oxytetracycline using a Oracet-Blue/Silver-Nanoparticle/Graphene-Oxide/Modified Screen-Printed Electrode

In this paper, an electrochemical technique is introduced for the determination of streptomycin (STR) in the presence of oxytetracycline (OTC) in milk samples. A novel bifunctional modified screen-printed electrode (SPE) modified with oracet blue, silver nanoparticles, and graphene oxide (OB/SNPs/GO/SPE) was fabricated. The modified electrode plays a catalyzer role for electrooxidation of STR at pH = 7.0 and reveals a facile a separation between the oxidation peaks of STR and OTC. Calculation of kinetic parameters such as the electron transfer coefficient α and the heterogeneous rate constant k´ of STR at the OB/SNPs/GO/SPE as 8.1 ± 0.07 cm s⁻¹ and 0.32 have been obtained based on the theoretical model of Andrieux and Saveant. A differential pulse voltammetric measurement demonstrates two linear dynamic ranges, 0.4 to 240.0 nM and 240.0 to 720.0 nM and a detection limit of 0.17 nM for STR. The sensitivities of the OB/SNPs/GO/SPE towards the oxidation of STR in the absence and presence of OTC were 2.625 × 10⁻¹ and 2.633 × 10⁻¹ µA/µM, respectively.

Electrochemical sensing of 2-methyl-4, 6-dinitrophenol by nanomagnetic core shell linked to carbon nanotube modified glassy carbon electrode

Electrochemical behavior and sensing of 2-methyl-4, 6-dinitrophenol as an herbicide has been investigated by cyclic voltammetry (CV) and square wave voltammetry (SWV). We have synthesized a cefazolin (CEF) immobilized nanomagnetic core-shell (Fe₃O₄@SiO₂-(CH₂)₃-CEF) and attached it on the modified glassy carbon electrode (GCE/MWCNT) through electrostatic adsorption (GCE/MWCNT/CEF-SiO₂@Fe₃O₄). 2-Methyl-4, 6-dinitrophenol has an oxidation peak that is related to the formation of nitrosamine from hydroxylamine species. This peak was applied for quantifying determination of 2-methyl-4, 6-dinitrophenol. The electrochemical oxidation involves two electron transfers accompanied by two protons. The electrochemical process was controlled by adsorption. The good agreement between the obtained computational studies and the experimental results has demonstrated that outer sphere electron transfer occurred on modified electrode. The new electrochemical sensor was applied to determination of 2-methyl-4, 6-dinitrophenol by SWV in the range of 1.0 × 10^-10 to 1.5 × 10^-7 M with a detection limit of 0.1 nM. The proposed sensor was applied for determination of 2-methyl-4, 6-dinitrophenol in water samples.

Pt-MWCNT modified carbon electrode strip for rapid and quantitative detection of H2O2 in food

A single-use screen-printed carbon electrode strip was designed and fabricated. Nanohybrids, prepared by deposition of platinum (Pt) nanoparticles on multi-wall carbon nanotube (MWCNT), was modified on the surface of screen-printed carbon electrode for the development of a fast, sensitive and cost-effective hydrogen peroxide (H2O2) detection amperometric sensor strip. With Pt-MWCNT nanohybrids surface modification, current generated in response to H2O2 by the screen-printed carbon electrode strip was enhanced 100 fold with an applied potential of 300 mV. Quality of as-prepared electrode strip was assured by the low coefficient of variation (CV) (<5%) of currents measured at 5 s. Three linear detection ranges with sensitivity of 75.2, 120.7, and 142.8 μA mM-1 cm-2 were observed for H2O2 concentration in the range of 1-15 mM, 0.1-1 mM, and 10-100 μM, respectively. The lowest H2O2 concentration could be measured by the as-prepared strip was 10 μM. H2O2 levels in green tea infusion and pressed Tofu could be rapidly detected with results comparable to that measured by ferrous oxidation xylenol orange (FOX) assay and peroxidase colorimetric method.