Development of tungsten trioxide nano-flakes intercalated on tannic acid-functionalized reduced graphene oxide for flexible acebutolol sensors

Acebutolol (ACE) is commonly used to treat hypertension and high blood pressure. Large doses of ACE can have adverse effects with potentially life-threatening consequences. It is, therefore, essential to develop a simple, low-cost, reliable, and reproducible device for detecting ACE in biofluids. This study explores the potential of unique two-dimensional nano-flakes, such as tungsten trioxide (WO3). Graphene oxide (GO) typically exhibits lower electrical conductivity than pristine graphene due to the presence of oxygen-containing functional groups that interfere with the π-conjugated structure. Functionalizing GO with tannic acid (TA) can partially reinstate the π-conjugation and limit the amount of oxygen, resulting in enhanced electrical conductivity. Ultrasonic techniques were utilized to create WO3 NFs@TA-rGO, and a range of spectroscopic and microscopic methods were applied to examine the formation of the resulting WO3 NFs@TA-rGO nanocomposites. Under optimal conditions, modified sensors resulted in lower limits of detection (0.0055 μM) and good sensitivity (0.40 μA μM-1 cm-2). They also exhibited a broad linear range spanning from 0.009 to 568.6 μM. Fabricated sensors have significant anti-interference properties with high specificity and excellent storage stability (RSD = 4.3 %), reproducibility (RSD = 3.9 %), and repeatability (RSD = 3.3 %). Ultimately, the sensor's efficacy was confirmed through the successful detection of ACE in biological samples (with recoveries ranging from 99.1 to 99.6 %). Lastly, this study highlights the substantial potential of ACE detection and extends its applications in biomedical diagnostics and pharmaceutical research.

Electro-sensing layer constructed of a WO3/CuO nanocomposite, for the electrochemical determination of 2-phenylphenol fungicide

The abstract highlights the development of an electroanalytical sensor for the detection of 2-phenylphenol (2-PPL) as a contaminant. The novelty of the experiment lies in the utilization of a 1-D nanostructured WO3/CuO nanocomposite integrated with a carbon paste electrode (CPE). The hydrothermal method was used to synthesize the WO3 NPs, which were then characterized using Scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS) techniques. Tungsten oxides (WO3) have been the subject of extensive study because of their many desirable characteristics, including their ease of preparation, tunable stoichiometry, crystal structure, particle morphology, 2.6 eV bandgap, excellent photocatalytic oxidation capacity, non-toxic nature, and widespread availability. The narrow band gap in CuO makes it an ideal sensing material. Copper oxide has applications in many different industries because it is a semiconductor metal with a narrow band gap in the spectrum of 1.2-1.9 eV and unique optical, electrical, and magnetic properties. Techniques like cyclic voltammetry (CV), and square wave voltammetry (SWV) were used. Real sample analysis was carried out in real-world samples like different types of soil, vegetables, and water. The electroanalytical sensor showed outstanding catalytic behavior by enhancing the peak current of the 2-phenylphenol with the potential shift to the less positive side compared to the unmodified carbon paste electrode in the presence of pH 7.0 phosphate buffer solution (PB). Throughout the experimental study, double distilled was used. Various electro-kinetic parameters like pH, accumulation time study, scan rate, concentration variation, standard heterogeneous rate constant, and participation of electrons, accumulation time, and transfer coefficient have been studied at WO3/CuO/CPE. The limit of detection was quantified together with the limit of quantification. Possible electrochemical oxidation mechanism of the toxic molecule was depicted. Overall, this research contributes to the field of electroanalytical sensing and offers potential applications in environmental monitoring.

Electrochemistry of Flavonoids: A Comprehensive Review

Flavonoids represent a large group of aromatic amino acids that are extensively disseminated in plants. More than six thousand different flavonoids have been isolated and identified. They are important components of the human diet, presenting a broad spectrum of health benefits, including antibacterial, antiviral, antimicrobial, antineoplastic, anti-mutagenic, anti-inflammatory, anti-allergic, immunomodulatory, vasodilatory and cardioprotective properties. They are now considered indispensable compounds in the healthcare, food, pharmaceutical, cosmetic and biotechnology industries. All flavonoids are electroactive, and a relationship between their electron-transfer properties and radical-scavenging activity has been highlighted. This review seeks to provide a comprehensive overview concerning the electron-transfer reactions in flavonoids, from the point of view of their in-vitro antioxidant mode of action. Flavonoid redox behavior is related to the oxidation of the phenolic hydroxy groups present in their structures. The fundamental principles concerning the redox behavior of flavonoids will be described, and the phenol moiety oxidation pathways and the effect of substituents and experimental conditions on flavonoid electrochemical behavior will be discussed. The final sections will focus on the electroanalysis of flavonoids in natural products and their identification in highly complex matrixes, such as fruits, vegetables, beverages, food supplements, pharmaceutical compounds and human body fluids, relevant for food quality control, nutrition, and healthcare research.

Electrochemical Polymerisation of Glutamic Acid on the Surface of Graphene Paste Electrode for the Detection and Quantification of Rutin in Food and Medicinal Samples

Rutin (RU) is one of the best-known natural antioxidants with various physiological functions in the human body and other plant species. In this work, an efficient voltammetric sensor to detect RU in food samples was explicated using a poly (glutamic acid)-modified graphene paste electrode (PGAMGPE). In order to detect RU, the proposed sensor diminishes material resistance and overpotential while increasing kinetic rate, peak currents, and material conductance. Using differential pulse voltammetry (DPV) and cyclic voltammetry (CV), the analysing efficiency of a PGAMGPE and a Bare graphene paste electrode (BGPE) was evaluated in 0.2 M phosphate buffer (PB) at an ideal pH of 6.5. in a potential window of -0.25 V to 0.6 V. Electrochemical impedance spectroscopy (EIS) was used to analyse the prepared electrode materials' conductivity, charge transfer resistance, and the kinetics of electron transport. Field emission scanning electron microscopy (FE-SEM) images were considered to compare the exterior morphology of the PGAMGPE and the BGPE. It was discovered that the PGAMGPE and the BGPE have electroactive surfaces of 0.062 cm² and 0.04 cm², respectively. It was determined that two protons and two electrons participated in the redox process. The resultant limit of detection (LOD) was found to be 0.04 µM and 0.06 µM, respectively, using DPV and CV methods. In spite of common interferents such as metal ions and chemical species, the developed sensor's selectivity for RU detection was impressive. For the simultaneous analysis of RU in the presence of caffeine (CF), the PGAMGPE affords a good electrochemical nature for RU with good selectivity. Due to the good stability, repeatability, reproducibility, and ease of use of the present RU sensor, it is useful for real sample analysis such as food and medicinal samples with recovery ranging from 94 to 100%.

A Comprehensive Review on the Electrochemical Sensing of Flavonoids

Flavonoids are bioactive polyphenolic compounds, widespread in the plant kingdom. Flavonoids possess broad-spectrum pharmacological effects due to their antioxidant, anti-tumor, anti-neoplastic, anti-mutagenic, anti-microbial, anti-inflammatory, anti-allergic, immunomodulatory, and vasodilatory properties. Care must be taken, since excessive consumption of flavonoids may have adverse effects. Therefore, proper identification, quantification and quality evaluations of flavonoids in edible samples are necessary. Electroanalytical approaches have gained much interest for the analysis of redox behavior and quantification of different flavonoids. Compared to various conventional methods, electrochemical techniques for the analysis of flavonoids offer advantages of high sensitivity, selectivity, low cost, simplicity, biocompatibility, easy on-site evaluation, high accuracy, reproducibility, wide linearity of detection, and low detection limits. This review article focuses on the developments in electrochemical sensing of different flavonoids with emphasis on electrode modification strategies to boost the electrocatalytic activity and analytical efficiency.

Highly sensitive electrochemical determination of rutin based on the synergistic effect of 3D porous carbon and cobalt tungstate nanosheets

Rutin, a flavonoid found in fruits and vegetables, is a potential anticancer compound with strong anticancer activity. Therefore, electrochemical sensor was developed for the detection of rutin. In this study, CoWO₄ nanosheets were synthesized via a hydrothermal method, and porous carbon (PC) was prepared via high-temperature pyrolysis. Successful preparation of the materials was confirmed, and characterization was performed by transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. A mixture of PC and CoWO₄ nanosheets was used as an electrode modifier to fabricate the electrochemical sensor for the electrochemical determination of rutin. The 3D CoWO₄ nanosheets exhibited high electrocatalytic activity and good stability. PC has a high surface-to-volume ratio and superior conductivity. Moreover, the hydrophobicity of PC allows large amounts of rutin to be adsorbed, thereby increasing the concentration of rutin at the electrode surface. Owing to the synergistic effect of the 3D CoWO₄ nanosheets and PC, the developed electrochemical sensor was employed to quantitively determine rutin with high stability and sensitivity. The sensor showed a good linear range (5–5000 ng/mL) with a detection limit of 0.45 ng/mL. The developed sensor was successfully applied to the determination of rutin in crushed tablets and human serum samples.

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Highly sensitive electrochemical sensor based on 3D porous carbon and CoWO₄ nanosheets.

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Electrochemical signal of rutin is mainly based on its concentration at the electrode surface.

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The introduction of porous carbon improved the electrochemical performance of 3D CoWO₄.

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The sensor was successfully applied to determine rutin in human serum samples.

Temperature abetted synthesis of novel magnesium stannate nanoparticles assisted for nanomolar level detection of hazardous flavonoid in biological samples

Fabrication of temperature-influenced nanoparticles over the superficial region of glassy carbon electrode (GCE) stimulates the electrocatalytic activity owing to their morphology, defective sites, and higher active surface area, etc. In this regard, we have fabricated annealed magnesium stannate nanoparticles (Mg₂SnO₄ NPs) on GCE for nanomolar level detection of hazardous flavoring and pharmaceutical compound Rutin (RT). To analyze the impact of temperature, we have compared annealed Mg₂SnO₄ NPs with unannealed magnesium stannate hydrate (MgSnO₃·3H₂O) particles. The physicochemical properties of synthesized materials were characterized with different microscopic and spectroscopic techniques. From these studies, annealed Mg₂SnO₄ NPs formed purely without any flith and existence of water molecules as compared to unannealed MgSnO₃·3H₂O. Moreover as fabricated, Mg₂SnO₄ NPs/GCE outcomes with higher redox behavior compared to other electrodes in presence of RT at optimized working buffer (pH = 7.0). Interestingly, the electrode successfully established a dual wider linear response (0.062-34.8 & 34.8-346.8 µM) with a nanomolar detection limit (1 nM) and higher sensitivity. The practicability analysis of the proposed sensor also affords excellent selectivity, reproducibility, repeatability, reversibility, and storage stability. Furthermore, the real sample analysis was carried out in blood and orange samples fallout with better recovery results.

Application of Electrochemical Sensors Based on Carbon Nanomaterials for Detection of Flavonoids

Flavonoids have a variety of physiological activities such as anti-free radicals, regulating hormone levels, antibacterial factors, and anti-cancer factors, which are widely present in edible and medicinal plants. Real-time detection of flavonoids is a key step in the quality control of diverse matrices closely related to social, economic, and health issues. Traditional detection methods are time-consuming and require expensive equipment and complicated working conditions. Therefore, electrochemical sensors with high sensitivity and fast detection speed have aroused extensive research interest. Carbon nanomaterials are preferred material in improving the performance of electrochemical sensing. In this paper, we review the progress of electrochemical sensors based on carbon nanomaterials including carbon nanotubes, graphene, carbon and graphene quantum dots, mesoporous carbon, and carbon black for detecting flavonoids in food and drug homologous substances in the last four years. In addition, we look forward to the prospects and challenges of this research field.

Simple synthesis of CoSn(OH)6 nanocubes for the rapid electrochemical determination of rutin in the presence of quercetin and acetaminophen

Schematic presentation of the synthesis of CoSn(OH)₆ nanocubes modified with SPCE towards the electrochemical detection of rutin.

Synergistic activity of binary metal sulphide WS2–RuS2 nanospheres for the electrochemical detection of the antipsychotic drug promazine

Schematic presentation for the synthesis of tungsten disulfide–ruthenium disulfide (WS₂–RuS₂) nanospheres and application for the electrochemical determination of antipsychotic drug promazine.