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The intensifying global opioid crisis, majorly attributed to fentanyl (FT) and its analogs, has necessitated the development of rapid and ultrasensitive remote/on-site FT sensing modalities. However, current approaches for tracking FT exposure through wastewater-based epidemiology (WBE) are unadaptable, time-consuming, and require trained professionals. Toward developing an extended in situ wastewater opioid monitoring system, we have developed a screen-printed electrochemical FT sensor and integrated it with a customized submersible remote sensing probe. The sensor composition and design have been optimized to address the challenges for extended in situ FT monitoring. Specifically, ZIF-8 metal-organic framework (MOF)-derived mesoporous carbon (MPC) nanoparticles (NPs) are incorporated in the screen-printed carbon electrode (SPCE) transducer to improve FT accumulation and its electrocatalytic oxidation. A rapid (10 s) and sensitive square wave voltammetric (SWV) FT detection down to 9.9 µgL-1 is thus achieved in aqueous buffer solution. A protective mixed-matrix membrane (MMM) has been optimized as the anti-fouling sensor coating to mitigate electrode passivation by FT oxidation products and enable long-term, intermittent FT monitoring. The unique MMM, comprising an insulating polyvinyl chloride (PVC) matrix and carboxyl-functionalized multi-walled carbon nanotubes (CNT-COOH) as semiconductive fillers, yielded highly stable FT sensor operation (> 95% normalized response) up to 10 h in domestic wastewater, and up to 4 h in untreated river water. This sensing platform enables wireless data acquisition on a smartphone via Bluetooth. Such effective remote operation of submersible opioid sensing probes could enable stricter surveillance of community water systems toward timely alerts, countermeasures, and legal enforcement.

Electron transfer in the electrode–solution interface is responsible for the signal in the electrochemical sensor. However, the Electrical Double-Layer (EDL) characteristic is usually ignored in signal modeling. Here, we constructed a model based on the reaction–diffusion equation to describe the dynamics in the EDL during sensing. With this model, many common experimental phenomena, such as transient/steady-state current variation or detection nonlinearization, can be unraveled by exploring the effects of position, kinetics proportionality coefficient (k), and reaction order (β). We also put forward some suggestions to improve the stability and linear detection range for future sensor design. [ABSTRACT FROM AUTHOR]

The degradation of organic dyes under visible light is an effective method to reduce environmental pollution. The key to implementing this method is to develop good photocatalysts. Under hydrothermal conditions, four polyoxometalate-based compounds were prepared, namely, [Co2(TPTP)4(H2O)4(SiMo12O40)]·4H2O (1), [Ni2(TPTP)4(H2O)4(SiMo12O40)]·2.5H2O (2), {[Cu(H2TPTP)(TPTP)(H2O)3]2(SiMo12O40)2}·7.5H2O (3), and {Cu2(TPTP)2(β-Mo8O26)1/2}·H2O (4) (TPTP = 4-[2-(5-pyridyl-4-yl-1,2,4-triazol-1-yl)-methyl]-pyran). Compounds 1 and 2 are isostructural, showing a two dimensional (2D) metal–organic layer. The Keggin anions are discrete between adjacent layers. Compound 3 contains a bi-supporting Keggin anion and a discrete anion. The TPTP ligands in 4 were linked by Cu atoms to form ladder like chains, which are connected by β-Mo8O264− anions to construct a 2D layer. The compounds can be used as photocatalysts. They have good separation efficiency of photogenerated electron–hole pairs. When compounds 1 and 2 were used as photoelectrocatalysts, they exhibited good photoelectrocatalytic activities. The compounds also exhibit excellent electrochemical performance and can be used as electrochemical sensors for the selective recognition of NO2− and Cr(VI). [ABSTRACT FROM AUTHOR]

The development of cost-effective and highly efficient electrocatalysts is critical to help electrochemical non-enzymatic sensors achieve high performance. Here, a new class of catalyst, Ru single atoms confined on Cu nanotubes as a single-atom alloy (Ru1Cu NTs), with a unique electronic structure and property, was developed to construct a novel electrochemical non-enzymatic glucose sensor for the first time. The Ru1Cu NTs with a diameter of about 24.0 nm showed a much lower oxidation potential (0.38 V) and 9.0-fold higher response (66.5 μA) current than Cu nanowires (Cu NWs, oxidation potential 0.47 V and current 7.4 μA) for glucose electrocatalysis. Moreover, as an electrochemical non-enzymatic glucose sensor, Ru1Cu NTs not only exhibited twofold higher sensitivity (54.9 μA mM−1 cm−2) and wider linear range (0.5–8 mM) than Cu NWs, but also showed a low detection limit (5.0 μM), excellent selectivity, and great stability. According to theoretical calculation results, the outstanding catalytic and sensing performance of Ru1Cu NTs could be ascribed to the upshift of the d-band center that helped promote glucose adsorption. This work presents a new avenue for developing highly active catalysts for electrochemical non-enzymatic sensors. [ABSTRACT FROM AUTHOR]

The FeTiO 3 nanopowder is a vital engineering material known for its exceptional performance in energy generation, storage, electrochemical sensors, and catalysis. However, synthesizing FeTiO 3 nanopowder with high crystallinity and phase purity typically requires specialized equipment and controlled heat treatment due to the instability of Fe2+ ions. Using the one-step solution combustion synthesis (SCS) method, FeTiO 3 nanopowder withe high crystallinity were successfully produced utilizing basic equipment. Additionally, the influence of carbon additives on phase transitions, as well as the physical and physicochemical properties of the synthesized powder, was examined. XRD results indicate that increasing the amount of fuel, particularly glycine, creates a stable environment for the crystallization of FeTiO 3 nanoparticles. Moreover, enhancing the carbon content in precursor solutions with urea enhances reduction conditions and boosts the stability of FeTiO 3 in the final product. The presence of carbon additives in glycine-fuel samples leads to unfavorable outcomes by increasing the levels of TiO 2 and Fe 3 O 4 undesirable phases. Incorporating additive carbon into the urea-synthesized precursor solution resulted in a particle size increase exceeding 50 nm and raised the combustion temperature by a minimum of 230 °C. Furthermore, the presence of 15 wt% additive carbon in the sample synthesized with glycine improved the specific surface area of particles from 2.44 m2/g to 18.41 m2/g. Obtained results have shown that achieving high crystallinity of FeTiO 3 nanopowder is feasible through a one-step solution combustion synthesis process. This can be accomplished by carefully choosing the synthesis conditions, such as the type and quantity of fuel, along with the carbon additive. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H2O2) has practical applications in healthcare, food security, and environmental protection. The current study has been focused on creating H2O2 sensors using a bimetallic composition of polypyrrole/Cobalt-silver on indium tin oxide (ITO) through electrochemical fabrication. Composite hybrid materials comprising Co@Ag/PPy/ITO were successfully synthesized using chronoamperometry and pulsed electrodeposition techniques. The obtained electrode (Co@Ag/PPy/ITO) was studied using scanning electron microscopy (SEM), ultraviolet–visible, and cyclic voltammetry techniques. The energy-dispersive X-ray spectroscopy and SEM revealed that silver and cobalt nanoparticles were distributed on the PPy surface, forming fern-like structures. A detailed investigation of the electrochemical properties of the bimetallic composition was conducted using cyclic voltammetry (CV), chronoamperometry, and electrochemical impedance spectroscopy. The amperometric method and CV were used to carry out the electrochemical detection of H2O2. The non-enzymatic H2O2 sensor exhibited an enhanced amperometry response, showing a higher sensitivity of 3.664 mA mM−1 cm−2 within a linear range spanning 0.12–2.36 mM. Notably, the sensor achieved a low detection limit of 1.985 μM (S/N = 3). Additionally, the nanocomposite hybrids demonstrated superior stability, repeatability, and reproducibility, making this sensor suitable for long-term use. [ABSTRACT FROM AUTHOR]

Efficient 2D-inorganic spinel perovskites nanostructure materials are used as potential candidates for highly sensitive detection of harmful substances present in the environment. In this regard, a facile one-pot hydrothermal synthesis was employed to fabricate nanocomposite material containing iron manganese oxide (FeMn 2 O 4) decorated with reduced graphene oxide (rGO) which is used as an electrochemical detection of metronidazole (MTZ). The crystalline nature and structural insights of the as-synthesized FeMn 2 O 4 -rGO nanocomposite were established using various spectroscopic and electrochemical techniques. Distinctively FeMn 2 O 4 -rGO nanocomposite fashioned glassy carbon electrode (GCE) showed excellent linear range (0.01–512.2 μM), sensitivity (71.4 μA mM−1 cm−2), limit of detection (0.0129 μM), reproducibility, stability and resist-interference capability towards metronidazole (MTZ) antibiotic drug. In addition, the fabricated FeMn 2 O 4 -rGO/GCE electrochemical sensor exhibited a remarkable MTZ detection in spiked water as well as urine samples with better recovery percentages supporting its facile and feasible nature for environmental applications. The present work established the fabrication of FeMn 2 O 4 -rGO/GCE nanocomposite for effective determination of antibiotic drugs in real sample analysis. [ABSTRACT FROM AUTHOR]

L-Cysteine is a semi-essential and proteinogenic amino acid, with the formula HO2CCH (NH2) CH2SH. L-cysteine is mostly found in protein-rich foods. In this study, catalysts consisting of cobalt (Co) supported on carbon nanotubes (CNTs) were prepared using the sodium borohydride (NaBH4) reduction method. These catalysts were characterized by means of energy-dispersive x-ray (EDX) with scanning electron microscopy (SEM), temperature-programmed reduction (TPR), and temperature-programmed oxidation (TPO) techniques. Characterization results confirmed the successful preparation of the desired catalyst. After preparing the Co/CNT catalysts, a highly efficient and sensitive electrochemical sensor was developed using a glassy carbon electrode (GCE) modified with the Co/CNT catalysts. The electrochemical behavior of the bare GCE and Co/CNT-modified GCE electrodes was investigated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS) in 0.1 M phosphate buffer solution (PBS) + L-cysteine. Electrochemical results showed that the Co/CNT-modified GCE electrode exhibited high sensitivity and selectivity compared to the bare GCE, with sensitivity of 0.0046 µA/µM, limit of detection of 0.2 µM, and limit of quantification of 0.6 µM. Furthermore, this electrode showed higher sensitivity values than those reported in the literature. Further interference studies were performed using CV and EIS to investigate interfering species in the serum environment, such as D-glucose, uric acid, L-tyrosine, and L-tryptophan. In conclusion, the results suggest that the Co/CNT-modified GCE electrode is a promising catalyst for the sensitive detection of L-cysteine. [ABSTRACT FROM AUTHOR]

Farmers aim to increase the yield of their crops by reducing their expenses. This prompts farmers to resort to smart farming practices. These practices facilitate the measurement and detection of nutrients in soil to maximize harvest with a low-cost sensor employing electrochemical and optical techniques. Potassium is a crucial macronutrient for the growth of plants. The excess or need for potassium in the soil can pose a risk to plants and the environment. Therefore, it is imperative to conduct soil monitoring to determine the quantity of soil fertilizer. ISFETs are among the most affordable and miniaturized sensors and are specific to one target ion. Although it is not time-consuming and requires an immediate response, the ISFET requires special calibration and sample preparation. This study tested ISFET on Moroccan soil potassium using a new technique of minimal sample preparation without needing a laboratory machine to extract soil using distilled water. The results indicate that the microsensor ISFET provided accurate results on solutions prepared in the laboratory with a correlation factor of 90%, and R² greater than 80% when estimating potassium levels in soil extracts. ISFET can therefore be used as an alternative method for potassium estimation. [ABSTRACT FROM AUTHOR]

N-(1,3-Dimethylbutyl)-N′-phenyl-1,4-benzenediamine (6PPD) is a common additive in tires. 6PPD protects rubber from oxidative damage by ozone. Leaching of 6PPD in the environment leads to the formation of harmful byproducts such as 6PPD quinone. In this work we provide the fundamental basis for the detection of 6PPD by electrochemical techniques. We use cyclic voltammetry to study the adsorption of 6PPD on glassy carbon. We show that adsorbed 6PPD can be reversibly oxidized and reduced without disturbing the adsorption process. This result enables repeated electrochemical titrations. We determine, in neutral condition at 22 °C, an adsorption constant of Kads = 1.2 ± 0.5 μM−1 and kinetics of adsorption kads∈[0.74–5.60] × 104 L mol−1 s−1. Based on this knowledge we demonstrate the lowest concentration of 6PPD ever detected electrochemically, 10 nM. We also identify current challenges for electrochemical sensing of 6PPD. Multiple layers are formed at concentrations above 4.6 μM and the slow kinetics of adsorption requires long (hour) measurement time to reach maximum sensitivity. [ABSTRACT FROM AUTHOR]

The design of electrochemical sensors is crucial considering important factors such as efficiency, low cost, biocompatibility, and availability. Manganese oxides are readily available, low-cost, and biocompatible materials, but their low conductivity limits their efficiency as sensors. Today, morphology engineering of manganese oxide has been one of the most common research topics, because manganese oxides' electrochemical properties are highly dependent on their morphologies. In this study, a method for reducing the charge transfer resistance (Rct) of MnO2-based electrodes was established by the cyclic voltammetry technique accompanied by step-by-step heat treatment to electrodeposition MnO2 nanofilm, which remarkably improved the Rct. Next, the sensing performance of MnO2/FTO for two separate measurements was examined, one for the simultaneous measurement of paracetamol (PAR) and 4-aminophenol (4-APh), and the other for the measurement of 4-nitrophenol (4-NP). Under the optimum conditions, the linear ranges of 4-APh, PAR, and 4-NP, were 0.8 to 22.0 µM, 2.0 to 55.0 µM, and 0.1–250 µM, with limits of detection (LOD) of 0.19 µM, 0.60 µM, and 0.01 µM, respectively. It also was unaffected by a 200-fold excess of interferences. In addition, the designed sensor was successfully applied to the analysis of real samples. [ABSTRACT FROM AUTHOR]

Dopamine is an important catecholamine neurotransmitter and its precise determination is of great significance in the diagnosis and treatment of related diseases. This study presents a high‐performance enzyme‐free electrochemical sensor for dopamine determination based on the combination of Prussian blue analogues oxides with multi‐walled carbon nanotubes (PBO@CNTs). The prepared PBO@CNTs exhibited an increased surface area of 49.79 m2/g with abundant mesoporous nanostructure, which providing numerous electroactive sites. Under the optimal conditions, the PBO@CNTs/Au exhibited a high sensitivity of 178.34 μA mM−1 cm−2, a broad linear range between 0.30 μM to 8 mM and a low detection limit of 0.10 μM. It displayed an excellent selectivity towards dopamine by the successive addition of various interfering species through chronoamperometry studies. Besides, the proposed electrodes enjoyed the excellent repeatability, reproducibility and long‐term stability. We also demonstrated the successful application of this sensor for the determination of dopamine in serum. The results indicated that the dopamine‐selective electrochemical enzyme‐free sensors have great potential in clinical application. [ABSTRACT FROM AUTHOR]

Molecular imprinting is an advanced technology in the fabrication of novel chemical sensors recently applied, enabling rapid responses and highly selective binding to specific molecules, thereby enabling efficient detection of material constituents. In this study, a new molecularly imprinted electrochemical sensor (MIES) utilizing ferrocene‐functionalized carbon‐nanotubes (Fc‐CNTs) was developed for the determination of tryptophan (Trp). The formation of molecularly imprinted polymer (MIP) involves polymerization in dimethyl sulfoxide (DMSO) using Trp, methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) as the template molecules, functional monomers, and cross‐linking agents, respectively. Due to the modification of MIPs, the sensor achieves high performance. The sensor demonstrates a linear range from 1 to 45 μM and from 45 to 330 μM, with the limit of detection of 0.44 μM, exceeding that of the majority of sensors reported in the literature. Furthermore, the sensor can effectively detect Trp in real samples, including human serum and amino acid oral liquid. The recovery rate of Trp in human serum samples is 94.2 % to 105.30 %, and in amino acid oral liquid is 94.3 % to 101.68 %. This study provides a promising approach for the effective detection and analysis of tryptophan constituents. [ABSTRACT FROM AUTHOR]

The current work reports a novel approach for the development of an electrochemical sensor based on Ni and Mg-co-doped ZnO nanoparticles (ZNMO) to detect and quantify cysteamine (CA). The chemical co-precipitation strategy was used to synthesize zinc oxide co-doped with magnesium and nickel which can be used as a catalyst material. FTIR, XRD, XPS, BET and SEM-EDX examinations were used to confirm the produced material. The surface of the glassy carbon electrode (GCE) was modified with ZNMO nanoparticles, resulting in a remarkable improvement in the surface area of the electrodes which in turn improved the response for CA compared to previously reported studies. This enhancement can be attributed to the superior catalytic activity of the material in electro-oxidizing CA. The electrochemical studies were carried out using the analytical techniques like cyclic voltammetry and differential pulse voltammetry using 0.1 M phosphate buffer saline as a supporting medium. This fabricated sensor, ZNMO nanoparticles modified GCE (ZNMO/GCE) has shown superior sensing characteristics, including high selectivity, sensitivity, stability, and repeatability, for the identification and quantification of CA. The sensor successfully confirmed the diffusion-controlled electrode technique. It exhibited the widest linear range, spanning from 1 nM to 2500 μM, which is the most impressive result ever reported. The limit of detection (LOD) was determined to be 0.75 nM. Additionally, at the developed sensor, a real-sample analysis was conducted using biological fluids. Hence, the fabricated ZNMO/GCE showed excellent electrocatalytic performance for CA sensing, making it suitable for real-time monitoring. [Display omitted] [ABSTRACT FROM AUTHOR]

Luteolin (Lut) is a flavonoid compound with antioxidant, anti-inflammatory and other biological properties. Lut has been used in many fields such as biomedicine and food safety. Therefore, the quantitative measurement of Lut is of great significance. In this study, an electrochemical sensor based on aminated multi-walled carbon (NH2-MWCNTs), sodium carboxymethylcellulose (CMC), ZIF-67 and chitosan (Chi) is developed for the measurement of Lut. NH2-MWCNTs are better dispersed by CMC, and NH2-MWCNTs are cross-linked with ZIF-67, which further improves the response and sensitivity of the electrode to the Lut due to the peroxide-like properties of ZIF-67. The detection limit and linear range of the electrochemical sensor for Lut are 2.1 nM and 0.1–7 μM, respectively. Dandelion is a traditional Chinese medicine plant containing Lut component. The prepared electrochemical sensor is also used to analysis Lut content in various parts of dandelion. The results show that the flowers part of dandelion exhibits the highest concentration of Lut; while, the leaves contain a moderate amount, and the roots are nearly devoid of Lut. These results are consistent with those obtained by ultra-high performance liquid chromatography. The electrochemical sensor has good stability and anti-interference ability, and has good potential application value in drug concentration detection and screening. [ABSTRACT FROM AUTHOR]

During the COVID-19 process, determination-based analytical chemistry studies have had a major place at every stage. Many analytical techniques have been used in both diagnostic studies and drug analysis. Among these, electrochemical sensors are frequently preferred due to their high sensitivity, selectivity, short analysis time, reliability, ease of sample preparation, and low use of organic solvents. For the determination of drugs used in the SARS-CoV-2, such as favipiravir, molnupiravir, ribavirin, etc., electrochemical (nano)sensors are widely used in both pharmaceutical and biological samples. Diagnosis is the most critical step in the management of the disease, and electrochemical sensor tools are widely preferred for this purpose. Diagnostic electrochemical sensor tools can be biosensor-, nano biosensor-, or MIP-based sensors and utilize a wide variety of analytes such as viral proteins, viral RNA, antibodies, etc. This review overviews the sensor applications in SARS-CoV-2 in terms of diagnosis and determination of drugs by evaluating the most recent studies in the literature. In this way, it is aimed to compile the developments so far by shedding light on the most recent studies and giving ideas to researchers for future studies. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs), are safe, biocompatible, bioactive, and biodegradable materials, and have sparked a lot of attention due to their unique characteristics in a variety of applications, including medical and dye industries, paper manufacturing and water purification. CNTs also have a strong film-forming potential, permitting them to be widely employed in constructing sensors and biosensors. This review concentrates on the application of CNT-based nanocomposites in the production of electrochemical sensors and biosensors. It emphasizes the synthesis and optimization of CNT-based sensors for a range of applications and outlines the benefits of using CNTs for biomolecule immobilization. In addition, the use of molecularly imprinted polymer (MIP)-CNTs in the production of electrochemical sensors is also discussed. The challenges faced by the current CNTs-based sensors, along with some the future perspectives and their future opportunities, are also briefly explained in this paper. RESEARCH HIGHLIGHTS: Review article on advanced Carbon-Nanotube (CNT)-based sensors and biosensors. The advantages of using CNTs for biomolecule immobilization and in electrochemical sensors and biosensors are discussed. The use of molecularly imprinted polymer-CNT nanocomposites in the production of electrochemical sensors is also discussed. Several characteristics, including sensor manufacturing, linear ranges, detection limits, and repeatability, are described in depth. Challenges and prospects using CNTs modified sensors have been proposed. [ABSTRACT FROM AUTHOR]

Heavy metals are commonly found in a wide range of environmental settings metals, but the potential toxicity associated with heavy metal exposure represents a major threat to global public health. It is thus vital that approaches to efficiently, reliably, and effectively detecting heavy metals in a range of sample types be established. Carbon nanomaterials offer many advantageous properties that make them well-suited to the design of sensitive, selective, easy-to-operate electrochemical biosensors ideal for detecting heavy metal ions. The present review offers an overview of recent progress in the development of carbon nanomaterial-based electrochemical sensors used to detect heavy metals. In addition to providing a detailed discussion of certain carbon nanomaterials such as carbon nanotubes, graphene, carbon fibers, carbon quantum dots, carbon nanospheres, mesoporous carbon, and Graphdiyne, we survey the challenges and future directions for this field. Overall, the studies discussed herein suggest that the further development of carbon nanomaterial-modified electrochemical sensors will support the integration of increasingly advanced sensor platforms to aid in detecting heavy metals in foods, environmental samples, and other settings, thereby benefitting human health and society as a whole. [ABSTRACT FROM AUTHOR]

Biopolymers are an attractive green alternative to conventional polymers, owing to their excellent biocompatibility and biodegradability. However, their amorphous and nonconductive nature limits their potential as active biosensor material/substrate. To enhance their bio-analytical performance, biopolymers are combined with conductive materials to improve their physical and chemical characteristics. We review the main advances in the field of electrochemical biosensors, specifically the structure, approach, and application of biopolymers, as well as their conjugation with conductive nanoparticles, polymers and metal oxides in green-based noninvasive analytical biosensors. In addition, we reviewed signal measurement, substrate bio-functionality, biochemical reaction, sensitivity, and limit of detection (LOD) of different biopolymers on various transducers. To date, pectin biopolymer, when conjugated with either gold nanoparticles, polypyrrole, reduced graphene oxide, or multiwall carbon nanotubes forming nanocomposites on glass carbon electrode transducer, tends to give the best LOD, highest sensitivity and can detect multiple analytes/targets. This review will spur new possibilities for the use of biosensors for medical diagnostic tests. [ABSTRACT FROM AUTHOR]

Graphene oxide-based nanomaterials are garnering significant attention from various fields due to their unique physical and chemical properties, which make them attractive for myriad applications. This feature article stems from Dr. Aicheng Chen's Lecture for the 2023 Ricardo Aroca Award of the Canadian Society for Chemistry and focuses primarily on the synthesis and applications of graphene oxide-based nanomaterials for electrochemical sensing. Graphene oxide (GO), reduced graphene oxide, and functionalized and doped GO-based nanomaterials are emerging as promising enablers of broad applications in electrochemical sensors. This is due to their distinctive functional groups and novel properties, which include high electrical conductivities, large surface areas, and enhanced catalytic activities. Several strategies for the synthesis of these nanomaterials are described in this feature article, encompassing the modified Hummers method, electrochemical, thermal, and microwave reactor methods. The characterization of these GO-based nanomaterials is highlighted, employing techniques such as scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, Raman, and X-ray photoelectron spectroscopy to study their morphologies, structures, and chemical compositions. The development of GO-based electrochemical sensors and their pharmaceutical, medical, environmental, and food safety applications are discussed. Further, the effects of these GO-based nanomaterials and different electrochemical techniques (e.g., cyclic voltammetry, square wave voltammetry, linear sweep voltammetry, and differential pulse voltammetry) on the performance of various electrochemical sensors are addressed. [ABSTRACT FROM AUTHOR]

Thallium (Tl), a heavy metal, has potentially harmful effects on human health due to its extreme toxicity. The determination of Tl is critical, and thus, there is a need for the development of electrochemical sensors that can swiftly identify its presence in the environment. A one-step hydrothermal synthesis of Prussian blue (PB) was utilized to adsorb thallium and electrochemically activate PB. The structure and morphology of PB were characterized through a scanning electron microscope, X-ray energy spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The PB-modified electrode's determination performance was optimized using the square wave voltammetry method. This included the optimization of support electrolyte, pH, deposition potential, and deposition time. Under optimal experimental conditions, the electrode demonstrated a favorable electrochemical response to thallium concentrations between 10 and 500 μg/L, with a detection limit of 1.94 μg/L. In summary, this sensor's outcomes are satisfactory and enhance the utility of PB nanomaterials in electrochemically detecting the heavy metal Tl. [ABSTRACT FROM AUTHOR]

The study of research proposes a systematic pattern for optimization and fabrication of a sustainable-cost effective electrochemical sensor made by Bi-CdFe2O4 (BCDF) nanoparticle and graphite powder. The structural examinations of synthesized BCDF materials were analyzed by specific spectral techniques viz.; P-XRD, SEM-EDX, TEM, XPS, FT-IR and DRS techniques. The modified sensor electrode offer a significant electrochemical properties that can improve the material selectivity and sensitivity actions measured by Cyclic Voltammetric (CV) and Electrochemical Impedance Spectral (EIS) plots. We demonstrated a developed highly-purity BCDF-graphite paste electrode for sensing actions on Paracetamol and Lead (Pb2+) ions under 0.1 M KCl. The excellent sensing activity towards Lead ions and Paracetamol confirmed by its redox potential peaks at scan rate of 1–5 V/s with maximum sensitivity of -0.61 V and 0.69 V respectively. The excellent photo-dye-degradation action of BCDF (98.2%) than those of host CDF (81.6%) on Rose Bengal (RB) dye was demonstrated. Its kinetic study reveals that this process follows first order kinetics and rate constants of the host (18.1 × 10−3 min−1) and BCDF (39.2 × 10−3 min−1) were measured. Thus, the synthesized BCDF electrode provides a new perception for developing specific nano-sensor towards detection of toxic metals. [ABSTRACT FROM AUTHOR]

A new electrochemical sensor for the highly sensitive and selective determination of dopamine was developed, based on the use of a glassy carbon electrode modified with cobalt(II) polymer. Both electrochemical and morphological characterizations were investigated. Square wave voltammetry (SWV) was used for the determination of dopamine. From the SWV results obtained on the modified electrode under the optimized conditions, the successive addition of dopamine increased the anodic peak current. The results obtained show a linear response of the electrode modified with Co(II) polymer in a wide concentration range. Each concentration decade is characterized by a new calibration plot with a corresponding mathematical expression. The highest sensitivity (13.182) was obtained for the lowest concentration range, and the detection limit of 0.03 µM, calculated based on the 3 × sb/m criterion, indicates a very high sensitivity and great application potential. When analyzing a real sample, the modified electrode showed good electroanalytical activities in terms of oxidation of dopamine, good anti-interference ability, stability, reproducibility, and potential applicability in commercial pharmaceutical samples. [ABSTRACT FROM AUTHOR]

Endosulfan is an organochlorine pesticide widely used in agriculture to protect crops such as cotton, soybeans, coffee, tea, cereals, fruits, vegetables, and grains from pests. However, exposure to low concentrations of endosulfan causes harmful effects on humans' health. Therefore, the determination of endosulfan in food samples by a fast, simple, and cost-effective method is pivotal. In this study, an electrochemical sensor based on a polyaniline/Fe-ZnO-modified glassy carbon electrode (PANI/Fe-ZnO/GCE) was developed for the determination of endosulfan in vegetables. The synthesized nanomaterials were characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). PANI/Fe-ZnO/GCE showed remarkable electrocatalytic activity for the determination of endosulfan in vegetables. It also exhibited a good linear response to endosulfan concentrations ranging from 1 to 400 µM. The method displayed a low detection limit (LOD) of 0.003 µM. The sensor showed good selectivity, long-term stability, good repeatability, and within-lab reproducibility. It was also applied for the determination of endosulfan in tomatoes and potatoes, with acceptable recoveries ranging from 87.00 to 96.80%. Graphical illustration of PANI/Fe-ZnO modified glassy carbon electrode for endosulfan determination in vegetables [ABSTRACT FROM AUTHOR]

The work reported herein describes the synthesis of a 3D material UiO-66(Zr)-NH-OC-MWCNT by combining a synthesized metal–organic framework UiO-66(Zr)-NH2 and a carboxy functionalized multi-walled carbon nanotube MWCNT-COOH via an amide linkage and demonstrated its application for simultaneous electrochemical determination of two benzimidazole fungicides-carbendazim and thiabendazole. Different analytical techniques like Fourier transform infrared spectroscopy, X-ray diffraction analysis, Brunauer–Emmett–Teller analysis, and Field emission scanning electron microscopy were employed to characterize all the synthesized materials. The electrochemical characterization of the fabricated electrode was carried out using cyclic voltammetry and electrochemical impedance spectroscopy. Cyclic voltammetry and differential pulse voltammetry techniques have been used for the electroanalysis of carbendazim and thiabendazole. A limit of detection of 0.077 µM and 0.557 µM, respectively, have been obtained in the calibration range of 0.1 to 40 µM for carbendazim and 1 to 40 µM for thiabendazole, after optimization of several parameters which are susceptible to the sensitivity and selectivity of the developed sensor. Furthermore, with satisfactory results from the study of interferences, repeatability, and reproducibility, the proposed electrochemical sensor was successfully applied for analysis of carbendazim and thiabendazole in real samples. [ABSTRACT FROM AUTHOR]

This work studies gold nanoparticle (AuNP) nucleation and growth mechanism from deep eutectic solvent (DES)-based choline chloride and glycerol (glyceline) onto glassy carbon electrode (GCE) and its application for DNA biosensor. Investigation of the current density transients indicated that the AuNPs were formed by the simultaneous presence of Au diffusion-controlled 3D nucleation and growth and residual water reaction over the Au nuclei growing surfaces. The AuNP structure was characterized by the field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. AuNPs were used to fabricate electrochemical DNA sensor. The hybridization was monitored by cyclic voltammetry and electrochemical impedance spectroscopy measurement using potassium ferri/ferrocyanide redox probes F e (C N) 6 3 - / 4 - as the indicator probe. Results show that the biosensor exhibited a linear correlation to the logarithm of the target DNA concentration ranged from 1.10−14 M to 1.10−9 M, and the limit of detection was 1.10−14 M. Furthermore, the findings indicate that the prepared electrode exhibited excellent reproducibility and long-term stability when applied for determining M. tuberculosis samples. [ABSTRACT FROM AUTHOR]

In this work, 5‐ferrocenyl‐dipyrromethane (Fc‐DPM) synthesized from the pyrrole and ferrocenecarboxaldehyde condensation was electrochemically deposited on a gold (Au) electrode and used to remove metal ions found in rural waters. The structural analysis of Fc‐DPM was recorded by means of nuclear magnetic resonance (NMR) techniques. The Fc‐DPM was electrochemically coated on an indium tin oxide‐polyethylene terephthalate (ITO‐PET) surface, and the resulting Fc‐DPM/ITO‐PET was characterized using scanning electron microscopy (SEM)–energy dispersive X‐ray (EDX) analysis. The heavy metal and mineral content of four real water samples from the same rural area were determined by inductively coupled plasma mass spectrometry (ICP‐MS) before and after electrochemical removal. The proposed Fc‐DPM/Au electrode was successfully applied for aluminum ion (Al3+) and barium ion (Ba2+) removal for the first time, and the limit of detection (LOD) was calculated as 0.003 and 0.217 ppb for Ba2+ and Al3+, respectively. [ABSTRACT FROM AUTHOR]

In this work, the application of three different Machine Learning algorithms, random forest (RF), support vector machine (SVM), and artificial neural network (ANN), to accurately classify ultra-low concentrations of Δ9-tetrahydrocannabinol in biological fluids such as saliva was successfully demonstrated. In doing so, experimental data consisting of the voltammetry signals of 0, 2, and 5 ng/mL of Δ9-tetrahydrocannabinol (THC) in synthetic and human saliva was employed. The dataset consists of person-to-person saliva variation and experimental variabilities in the procedure and artifacts. The results showed that RF was the most robust ML technique to classify different concentration levels of THC in the presence of a variety of variabilities in the experimental data, with an average training accuracy of 96% and an average testing accuracy of 87%. On the other hand, SVM and ANN models were susceptible to incoherencies in the experimental data. [ABSTRACT FROM AUTHOR]

We propose here a fabrication of an electrochemical sensor to detect heavy metal ions based on a glass carbon electrode (GCE) modified with a composite system consisting of graphene, chitosan, and Fe3O4 nanoparticles (GrCF) by using square wave voltammetry (SWV) measurements. The GrCF composite was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and Raman spectroscopy. GrCF consists of thin and smooth sheets stacked in overlapping layers to form porous structures. In the GrCF composite, graphene acts as a substrate with a high electrochemical activity and a good electrical conductivity, Fe3O4 nanoparticles are uniformly distributed on the graphene thanks to chitosan as a binder, the functional groups of chitosan (− OH, − NH2) have the ability to form complexes with heavy metal ions, and the excellent adsorption capacity of Fe3O4 nanoparticles has enhanced the electrochemical reactions. The GrCF/GCE can detect Pb2+ ions with a linear range from 4 to 16 μM, a low detection limit of 3.57 μM, and a sensitivity of 8.623 μA μM−1. Furthermore, the repeatability of the measurements are reliable with a standard deviation (SD) of 0.15 μA and a relative standard deviation (RSD%) of 4.16%. Additionally, Pb2+ was detected in the real sample at potentials of − 0.50 V/ − 0.52 V with calculated recovery values for two measurements of 89.02% and 89.43%. The electrode modification method based on the GrCF composite promises outstanding advantages in the field of electrochemical sensors for detection of heavy metal ions. [ABSTRACT FROM AUTHOR]

The Co2O3-Chitosan composite (Co@Chitosan) nanoparticles were synthesized through a green approach. The composite under investigation was characterized by various analytical methods, including scanning electron microscopy (SEM), transmitted electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and atomic force microscope (AFM) confirming the preparation step. The modified composite's performance was evaluated for its potential applications in nitrite sensing and hydrogen production by utilizing diverse electrochemical methodologies. The Co2O3-Chitosan that has been modified exhibits a linear detection range of 0.25–100 µM and a limit of detection (LOD) of 0.117 µM with a response time of approximately 5 s using the amperometry technique. Furthermore, the utilization of Co2O3-Chitosan composite as a proficient catalyst for hydrogen generation in an alkaline environment was implemented. The electrode exhibited enduring stability in fuel generation and heightened energy safeguarding. The current density of the electrode was observed to attain a value of η 50 at − 0.55 and − 0.43 V (versus RHE) for Co2O3 and Co@Chitosan, respectively. The study investigated the durability of electrodes during extended periods of constant potential chronoamperometry lasting 6 h. The Co2O3 and Co@Chitosan exhibited a reduction in initial current by 11% and 7%, respectively. [ABSTRACT FROM AUTHOR]

In recent years, the development of highly sensitive and selective electrochemical sensors has been a pivotal area of research, driven by the growing demand for environmental monitoring and industrial process control. Among various materials investigated for sensor applications, manganese oxide (MnO2) nanoparticles have garnered significant attention due to their excellent electrochemical properties, environmental friendliness, and natural abundance. Critical analyses of the synthesis of MnO2 using different techniques such as hydrothermal method, chemical precipitation, and sol–gel process which allows for the fine-tuning of particle size and morphology while enhancing the electrochemical sensing capabilities have been reviewed. The review also provides a comprehensive overview of the recent advancement evaluation of manganese oxide-based electrodes for detecting sulfonamides and other analytes in water across diverse matrices. This paper sets the stage for a comprehensive exploration of the synthesis methods and application areas of MnO2 nanoparticles in electrochemical sensors, highlighting their role in advancing sensor technology and their impact on various sectors. [ABSTRACT FROM AUTHOR]

3D printing technology has driven the development of flexible and stretchable electronic devices. In this field, silver‐based silicone rubber composites have emerged as promising materials due to their commendable conductivity, stretchability, and printability. However, the manufacturing of stretchable silver electrode materials at room temperature faced significant challenges, including intricate ink preparation methods, phase separation requiring high‐temperature annealing, and subpar conductivity. To address these issues, SP‐RTV ink was developed by mechanically blending room‐temperature vulcanized silicone rubber (RTV) with commercial conductive silver paste (SP). Subsequently, the 3D‐printed SP‐RTV electrodes were both stretchable and curable at room temperature, demonstrating excellent conductivity across various substrates. By optimizing the ink ratio, we achieved outstanding electrical conductivity of 5.17 × 105 S/m for the SP‐RTV electrode comprising 90 wt% silver paste. Moreover, the SP‐RTV electrodes containing 70 wt% silver paste exhibited excellent stretchability of 110% along with a gauge factor of 14.87, making them suitable for detecting finger and wrist movements. Additionally, the 80 wt% SP‐RTV maintained stable relative resistance changes during stretching, positioning it aptly for intrinsic stretchable organic electrochemical transistor applications. Overall, this study offers valuable insights into the room‐temperature manufacturing of flexible electrodes, paving the way for advancements in this burgeoning field. [ABSTRACT FROM AUTHOR]

Excessive intake of nitrite causes serious health problems. Monitoring nitrite levels is necessary for protecting both human health and the environment. Therefore, the fabrication of sensors for rapid detection of nitrite was the aim of this work. We proposed a new method based on an electrochemical sensor prepared from polyrhodamine B (PRhB) coating deposited on polylactic acid modified carbon black (PLA-CB) electrode. The synthesized PRhB/PLA-CB sensor is selective and efficient for nitrite detection, which is based on the interaction between the dimethylamino group of PRhB and nitrite and it has both the advantages of simple preparation and low cost. In optimal experimental conditions, the results of cyclic voltammetry showed that PRhB/PLA-CB, showed significant improvement of the electro-catalytic performance (20%) compared to bare PLA-CB thanks to due to the large surface area and porosity provided by PLA-CB combined with the conductivity and catalytic activity of PRhB. The coating was characterized using the scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The effects of pH and scan rate on nitrite detection were evaluated. The modified electrodes exhibited a remarkable electro-catalytic performance with a wide linear range of 1-10000 µM and low limit of detection (LOD) of 0.342 µM and limit of quantification (LOQ) of 1.036 µM. The proposed sensor was used for the detection of nitrite in tap and commercial water showing good recovery results. [ABSTRACT FROM AUTHOR]

The accurate monitoring of lactate level is very important in the fields of food quality and sport. In the present work, an effective sensor was introduced for lactate monitoring in food and in human bio-fluid. The non-enzymatic electrochemical sensor was fabricated by bulk modification of a simple carbon paste electrode (CPE) with iron-copper ferricyanide (ICF) catalyst and room temperature ionic liquid (IL). The lactate sensing capabilities of the suggested sensor are significantly enhanced due to the combination of the high conductivity of IL and the improved catalytic properties of the ICF modifier. The chronoamperometric response measurements of the ICF-IL-CPE demonstrated a high sensitivity towards lactate across a broad linear range of 20 to 1000 µM, with a correlation coefficient of R2 = 0.999. This sensor also exhibited a detection limit of 4.5 µM, a reproducibility of 3.9% relative standard deviation, and a stability of 95.8% over a period of five weeks. The suggested ICF-IL-CPE depicted minimal background interference against common interfering species. This makes it a highly promising tool for accurately measuring lactate concentrations in various samples including saliva from athletes and cow milk. [ABSTRACT FROM AUTHOR]

Due to the fusion of culinary cultures, chili products have gained widespread popularity among consumers. Capsaicin, the primary compound responsible for the spiciness of chili products, serves as a pivotal parameter in assessing the quality of chili peppers. A three-dimensional (3D) cell-based electrochemical sensor was developed to detect capsaicin by monitoring the release of hydrogen peroxide (H2O2). The working electrode utilized in this study was a screen-printed carbon electrode (SPCE) that had been modified with AuPtNPs/ZIF-8-RGO. Encapsulation of HepG2 cells within a 4.0 wt% sodium alginate gel enabled their immobilization onto the working electrode, thus serving as the biometric element for signal recording via the amperometric i-t method. H2O2 kit assays showed that H2O2 release increased with increasing capsaicin concentration over a range of concentrations. With a detection limit of 0.848 μM, the developed biosensor effectively detected capsaicin at concentrations that varied from 10 μM to 120 μM. The sensor that was developed displayed exceptional sensitivity, stability, and reliability, offering a novel method for monitoring capsaicin level in food. [ABSTRACT FROM AUTHOR]

Excessive nitrite () addition poses a significant threat to food safety. Thus, it is desirable to construct a selective and dependable electrochemical sensor for the quantitative measurement of . In this study, an electrochemical sensor using nitrogen-rich porous carbon (NPC) derived from graphitic carbon nitride (g-C3N4) was developed for the quantitative detection of . The NPC synthesis involved a two-step process, namely polymerization and carbonization. The carefully designed polymerization method and optimal carbonization condition yielded an NPC material with a relatively high surface area of 593.36 m²·g⁻¹. Notably, NPC nanomaterials exhibited a high nitrogen content of 19.8%, comprising various nitrogen species (pyridinic N, pyrrolic N, and oxidized N) that are fully faradaic-active N species, leading to enhanced electrochemical properties and sensitivity. The calibration plot exhibited linearity within the concentration range of 2-3410 µM, LOD of 0.11 µM, a sensitivity of 11.32 µA·µM− 1 cm− 2 and further showed excellent adaptability in real sample analysis. This innovative way of creating electrochemical sensors from nitrogen-rich porous carbon materials broadens the scope of electroanalysis and provides a beneficial means of guaranteeing food safety. [ABSTRACT FROM AUTHOR]

Alpha-lipoic acid (α-LA) is a naturally occurring compound that is both water and fat soluble, functioning as a powerful antioxidant in the body. In this study, multi-walled carbon nanotubes (MWCNTs) with SDS were electrodeposited onto a glassy carbon electrode (GCE) electrochemically. This modified electrode was characterized by electrochemical techniques (EIS, CV). The MWCNT/SDS-modified GCE was utilized for the analysis of α-LA. An electrochemical oxidation mechanism for α-LA was proposed using the developed electrochemical sensor. After optimizing the conditions, the MWCNT/SDS-GCE sensor exhibited a linear response in the concentration range of 0.6–9.0 µM, with a detection limit of 0.15 µM. Additionally, this chemical sensor was effectively utilized for the electrochemical analysis of α-LA in the food additive sample. [ABSTRACT FROM AUTHOR]

Nanozymes, synthetic nanomaterials that mimic the catalytic functions of natural enzymes, have emerged as transformative technologies for biosensing, diagnostics, and environmental monitoring. Since their introduction, nanozymes have rapidly evolved with significant advancements in their design and applications, particularly through the integration of machine learning (ML). Machine learning (ML) has optimized nanozyme efficiency by predicting ideal size, shape, and surface chemistry, reducing experimental time and resources. This review explores the rapid advancements in nanozyme technology, highlighting the role of ML in improving performance across various bioapplications, including real-time monitoring and the development of chemiluminescent, electrochemical and colorimetric sensors. We discuss the evolution of different types of nanozymes, their catalytic mechanisms, and the impact of ML on their property optimization. Furthermore, this review addresses challenges related to data quality, scalability, and standardization, while highlighting future directions for ML-driven nanozyme development. By examining recent innovations, this review highlights the potential of combining nanozymes with ML to drive the development of next-generation diagnostic and detection technologies. [ABSTRACT FROM AUTHOR]

High‐performance sensors are in constant demand for health care and environmental protection. In this study, a sensitive paracetamol (PCM) sensor was designed by modifying glassy carbon electrode (GCE) with carbon‐doped boron nitride (BCN/GCE) nanosheets. The BCN nanosheets were synthesized using a molten‐salt method, which ensured the uniformity of size distribution. X‐ray diffraction and transmission electron microscopy results suggested that the carbon‐doping hardly changed the crystal structure and morphology of hexagonal boron nitride (HBN). However, the carbon‐doping can reduce the bandgap, increase the specific surface area and improve the electrical conductivity, which is attributed to the formation of abundant point defects in the BN crystal. These point defects modulate electronic structure and surface activity, and further improve the electrocatalytic properties of BN. The BCN nanosheets exhibited outstanding electrocatalytic activity in the oxidation of paracetamol (PCM). With the help of square wave voltammetry (SWV) method, the BCN/GCE demonstrated linear current response towards PCM covering the concentrations of 0.05–70 μM and 70–200 μM with a detection limit (LOD) of 0.0086 μM. The developed method also showed excellent selectivity and high stability. In addition, the BCN/GCE sensor worked well when it was applied to quantify PCM in actual samples. [ABSTRACT FROM AUTHOR]

Sunset Yellow (SY) is an azo dye used in various food and pharmaceutical industries that deserves special attention because of its allergic and carcinogenic properties. Recently, electrochemical techniques have come to the spotlight because of their high sensitivity, simplicity and rapidity as compared to other techniques. In this work, we have developed a cost‐effective and stable electrochemical sensor by a simple method using Vitamin B12‐derived cobalt oxide coupled with g‐C3N4 (V12‐CoO/gCN) modified Au electrode. The composite prepared for the sensor was characterized using techniques such as FTIR, Powder XRD, SEM analysis, EDAX, and mapping. For electrochemical sensing of the dye Sunset Yellow, CV, DPV, and LSV techniques have been used, out of which DPV shows a better detection limit of 1.39 nM followed by LSV and CV that displayed detection limits of 3.3 nM and 4.14 nM respectively. When 5 real samples obtained from the local market are analyzed using the DPV technique, the detection limit is obtained in the range between 2.1 nM and 6.9 nM. This method leads to the development of an electrochemical sensor for the detection of Sunset Yellow to get a lower detection limit that can be used in food toxicology and related fields. [ABSTRACT FROM AUTHOR]

Flexible and biodegradable electronics have emerged as a promising solution for escalating electronic waste issue caused by the rapid development of skin patch electronics. Fully biodegradable displays are essential for visualizing biological/physical/chemical/electrochemical signals measured by a wide range of skin patch electronics. Here we propose fully biodegradable electrochromic display providing low operating voltage and low power consumption. The biodegradable transparent conductive electrode was fabricated by transferring free-standing tungsten nanomesh onto poly lactic-co-glycolic acid substrate using electrospinning templating, minimizing damage to the substrate. Electrochromic layer was tungsten oxide which is biodegradable, and a ferrocyanide/ferricyanide redox agent was utilized as a counter electrode reaction to enhance operational stability in an aqueous electrolyte by reducing operating voltage and side reactions. This display successfully visualized diverse signals from various biodegradable electronics such as UV sensors and electrochemical transistors, and finally underwent eco-friendly degradation in phosphate-buffered saline or soil under mild conditions. [ABSTRACT FROM AUTHOR]

AbstractAn overview of the latest advances in the design of electrochemical sensor architectures dedicated to the determination of drugs from the statin class is presented in this review. Statins are drugs widely consumed for cholesterol control, and their determination in different matrices through the application of electroanalysis is growing considering advantages such as operational simplicity, lower cost and ease of sample preparation. Within the context of statins, electrochemical sensor architectures can be subdivided into conventional/classical electrodes such as glassy carbon electrodes, carbon paste electrodes, pencil graphite electrodes, boron-doped diamond electrodes and metallic electrodes, and more modern electrode systems, including the screen-printed electrodes and 3D-printed electrodes. Thus, different aspects related to the preparation of these electrochemical sensors and analytical performance are presented, also reflecting advances in terms of designs of new architectures and possible improvements not previously reviewed. Analyzed samples, advantages and disadvantages of different implemented sensor’s modification strategies and perspectives for the electroanalysis of statins are also included throughout the work. [ABSTRACT FROM AUTHOR]

Methyldopa, a synthesized dopamine substitute with phenolic, amine, and carboxylic groups, was used to create a selective molecular imprinted polymer (MIP) for detecting formoterol fumarate dihydrate (FFD), a long-acting beta2-agonist for asthma and COPD. The bio-inspired polymer (MD) was electro-grafted onto a pencil graphite electrode (PGE) using cyclic voltammetry in a phosphate buffer (pH 6.5). An indirect method involving a redox probe (ferrocyanide/ferricyanide) and differential pulse voltammetry measured FFD binding to the MIP's 3D cavities. The sensor showed a linear response range from 1 × 10⁻⁹ M to 2 × 10⁻¹⁰ M, with a detection limit of 1.7 × 10⁻¹¹ M. The polymethyldopa (PMD) and FFD interaction was assessed by UV spectroscopy, and the method was validated per ICH guidelines. Green analytical approaches, including RGB and GAPI, were also implemented. The goal was to use advances in molecularly imprinted polymers to develop a more precise and selective electrochemical sensor for FFD quantification. [ABSTRACT FROM AUTHOR]

A hierarchical heterogeneous composite electrode of NiFe2O4@nitrogen‐doped multi‐walled carbon nanotubes/carbon cloth (NFO@N‐MWCNTs/CC) is prepared via a dip‐coating method, followed by a hydrothermal process. The flexible carbon cloth (CC) substrate provides robust support and the cross‐linked nitrogen‐doped multi‐walled carbon nanotubes (N‐MWCNTs) on the CC form a highly porous network with a large specific area that facilitates electron‐transfer. The stable support strengthens the framework and prevents pore structure disorder within the porous network, that could lead to the structural instability of the active sites. The decorated NiFe2O4 nanoparticles offer abundant active sites for enhanced electrocatalytic activity. Benefiting from the synergistic effect of the 3D hierarchical heterogeneous microstructure and multilevel bimetallic oxide active site (Ni/Fe‐O‐N‐C) constructs, the NFO@N‐MWCNTs/CC electrode achieves stable detection of multiple heavy metal ions (HMIs) with high reproducibility. The modified electrode allowed stable detection of multiple heavy metal ions with high reproducibility. The sensitivities of the electrode for Cd(II), Pb(II), Bi(III), and Hg(II) are 344.98, 441.02, 176.484, and 371.099 µA µm−1, respectively. The assay recoveries ranged from 95.3% to 106.8%, highlighting its practical applicability. This study provides innovative composites and theoretical insights to facilitate further advances in the simultaneous high‐performance detection of heavy metal ions. [ABSTRACT FROM AUTHOR]

Glass nano/micron pipettes, owing to their easy preparation, unique confined space at the tip, and modifiable inner surface of the tip, can capture the ion current signal caused by a single entity, making them widely used in the construction of highly sensitive and highly selective electrochemical sensors for single entity analysis. Compared with other solid-state nanopores, their conical nano-tip causes less damage to cells when inserted into them, thereby becoming a powerful tool for the in situ analysis of important substances in cells. However, glass nanopipettes have some shortcomings, such as poor mechanical properties, difficulty in precise preparation (aperture less than 50 nm), and easy blockage during complex real sample detection, limiting their practicability. Therefore, in recent years, researchers have conducted a series of studies on glass micropipettes. Ionic current rectification technology is a novel electrochemical analysis technique. Compared with traditional electrochemical analysis methods, it does not generate redox products during the detection process; therefore, it can not only be used for the determination of non-electrochemically active substances, but also causes less damage to the cell/living body in situ analysis, becoming a powerful analysis technology for the in situ analysis of cells/in vivo in recent years. In this review, we summarize the preparation and functionalization of glass nano/micron pipettes and introduce the sensing mechanisms of two electrochemical sensing platforms constructed using glass nano/micron pipette-based ion current rectification sensing technology as well as their applications in single cell/in vivo analysis, existing problems, and future prospects. [ABSTRACT FROM AUTHOR]

In this study, dibenzosuberenone (DBS)-based non-enzymatic electrochemical sensors are fabricated and investigated against four different analytes. In the sensor test measurements, it is concluded that the fructose detection performance of the DBS-based sensor is higher than the glucose, maltose, and lactose detection performances. It is observed that this non-enzymatic electrochemical sensor against fructose for all concentration responses indicating reduction and oxidation redox reactions, increases steadily as the concentration increases. The fructose detection limit of the sensor is 8.33 μM in 1 min voltammetric cycle. The sensor detected fructose with 25.92 μAmM−1 sensitivity. Since prepared DBS-based non-enzymatic electrochemical sensors exhibit significant sensitivity, they have potential to be successfully applied in the detection of fructose in a food. This study provides a simple sensor platform for sensitive detection of fructose in foods. In addition, the conductivity and impedance results of all DBS-based sensors are related to each other and are an effective parameter in the current density and sensitivity of the sensors. The high sensitivity of the sensors is associated with their impedance and conductivity. [ABSTRACT FROM AUTHOR]

The accurate and rapid detection of persulfate concentration is important for environmental decontamination and human health protection. In this work, a novel self-powered electrochemical sensor for the sensitive monitoring of persulfate was developed, which utilized cobalt tetroxide (Co3O4@CC) or tin-doped cobalt tetroxide (SnxCo3−xO4@CC) cathode as the sensing element and anode with electrogenic microorganisms as the power supplier. The Co3O4@CC and SnxCo3−xO4@CC electrodes were fabricated by in situ growing nanostructured Co3O4 or SnxCo3−xO4 catalysts on carbon cloth. Electrochemical tests revealed that these electrodes exhibited excellent catalytic reduction performance toward persulfate because of the synergistic catalysis by Co3O4 and electrode electrons, well-exposed Co2+/Co3+ catalytic sites, and high electron transfer efficiency. Tin doping could enhance the catalytic persulfate reduction by improving the conductivity and electron transfer of the Co3O4 catalyst. The electrode prepared at a hydrothermal temperature of 90 °C and a tin dosage of 0.286 g·cm−2 achieved the highest persulfate reduction activity under pH 7. The sensing properties of the self-powered sensors toward persulfate were explored in detail. Results showed that under the optimal external load of 300 Ω, the proposed sensor could display a broad detection range of 0 to 1500 μmol L−1 K2S2O8 with sensitivities of 1.13 and 0.12 μA μmol−1 L, a detection limit of 1.11 μmol L−1 (S/N = 3), and a fast response time within 30 s. The sensors also presented satisfactory reproducibility and selectivity during the detection of persulfate. The proposed sensor will provide a new approach for sensitive, on-site, and real-time monitoring of persulfate for a wide range of applications. [ABSTRACT FROM AUTHOR]

Sustainable synthesis of novel Calcium magnesium ferrite nanomaterial was carried out in this work using aloe vera plant extract as a fuel for the combustion method. Structural characterizations of the synthesized material shows the crystallite size∼ 14 nm with cubic structure and chemical bonds between Ca−O and Fe−O. Porous nature and agglomerated particles were observed in morphological analysis. Modified carbon paste, glassy carbon and screen printed electrodes were prepared using the synthesized nanomaterial for biomolecules sensing using cyclic voltammetry technique. Therefore, the present green synthesized CMF nanoparticles modified carbon paste electrode shows significantly high sensitivity and hence it can be used as a sensor for biomedical application. Employing the agar disc diffusion technique, the antimicrobial activity of the synthesized nanoparticles was ascertained. C against the pathogens like Pseudomonas spp., E coli, and Staphylococcus spp. [ABSTRACT FROM AUTHOR]

Additive manufacturing technology is renowned for its ability to produce components on demand. Presently, the development of sustainable materials has been promoted by Green Chemistry, leading to an increase in the recycling of polymers and other materials for use in 3D printing. In this work, we proposed the construction of a 3D printed electrochemical device using a conductive paste made from 3D printing residues of acrylonitrile butadiene styrene (ABS) filaments and graphite to develop a sustainable sensor for acebutolol detection using square wave voltammetry method. The electrode was characterized using imaging and electrochemical techniques, demonstrating superior electrochemical performance compared to a commercial device. The method exhibited excellent analytical performance with a linear working range from 0.98 to 51.8 μmol L−1 and good detectability (detection limit) of 0.28 μmol L−1. Furthermore, the recycled sensor demonstrated good precision with a relative standard deviation of less than 8.4 % and good accuracy with recovery percentages ranging from 93 to 107 % for monitoring acebutolol in urine and tap water samples. Additionally, the device was free from interference from the matrix and other commonly used drugs, making it suitable for electroanalytical applications and extremely promising. [ABSTRACT FROM AUTHOR]

Nanoclays are layered structures in the nanoscale range with widespread application due to their unique properties such as swelling, cation exchange capacity, and ease of functionalisation using metals, metal oxides, and organic compounds such as carbon paste, polymers, and other biomolecules that form nanoclay composites. Nanoclay functionalisation with silver (Ag), zinc oxide (ZnO), and bimetallic silver-gold (Ag-Au) using hydrophilic and hydrophobic clays is here evaluated and discussed. The composites' synthesis and morphological, crystallinity, and electroactive properties in comparison with pure nanoclay are also assessed. The layered structure and crystallinity of all these nanoclay composites were slightly changed. The clumped layered structures on the surface of the nanocomposites had dispersed white spots that indicated possible surface modification. The nano-films of the composites' electroactivity were comparatively high, as seen from the increase in current in the cyclic voltammetry characterisation voltammograms and the differential pulse voltammograms of the pharmaceutical detection. Efavirenz, nevirapine, and zidovudine detection was improved by modification of the nanocomposite with human serum albumin (HSA), as shown by the higher current, thus indicating improved conductivity of the composites compared to the pure nanoclays. Applying HAS-modified nanocomposites in the analysis of efavirenz, nevirapine, and zidovudine on a glassy carbon electrode (GCE) showed good linearity and acceptable detection limits comparable to those of previous studies. Therefore, it has potential for application in pharmaceutical quality control and environmental monitoring. [ABSTRACT FROM AUTHOR]