LaNi0.5Ti0.5O3/CoFe2O4-based sensor for sensitive determination of paracetamol

A novel Co/Zn-ferrite molecularly imprinted polymer-based electrochemical assay for sensing of gallic acid in plant extracts, wine, and herbal supplement

In this study, a new molecularly imprinted polymer (MIP)-based sensor platform was developed for the electrochemical determination of gallic acid (GAL) in plant extracts, wine, and herbal supplements. Gallic acid is known for its natural antioxidant properties, which play an important role in preventing cell deterioration that can lead to various diseases. In addition, gallic acid has therapeutic potential due to its anticancer, antiinflammatory, antimicrobial, and neuroprotective properties. Accurate analysis of gallic acid in complex matrices, in mixed samples where different components coexist, is necessary to evaluate the efficacy and safety of this compound. Cobalt ferrite-zinc-dihydro caffeic acid (CFO_Zn_DHCA) nanoparticles, sphere-like in shape and 5 ± 1 nm in size, were incorporated into the MIP-based electrochemical sensor design to enhance the active surface area and porosity of the glassy carbon electrode (GCE) surface. The functional monomer chosen for this study was aminophenyl boronic acid (3-APBA). In the GAL/CFO_Zn_DHCA/3-APBA@MIP-GCE sensor, which was developed using photopolymerization (PP), 3-APBA as a functional monomer was designed, and obtained in the presence of basic monomer (HEMA), cross-linker (EGDMA), and initiator (2-hydroxy-2-methyl propiophenone) by keeping it under a UV lamp at 365 nm. It aims to detect GAL in real samples such as Punica granatum (pomegranate) peel, Camellia sinensis (green and black tea leaves), wine, and herbal supplements. Morphological and electrochemical characterizations of the designed GAL/CFO_Zn_DHCA/3-APBA@MIP-GCE sensor were carried out using scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The linear range for the determination of GAL using the indirect method (5.0 mM [Fe(CN)6]-3/-4) was found to be 1.0 × 10-13 M-1.0 × 10-12 M, and the limit of detection (LOD) and limit of quantification (LOQ) for standard solutions were calculated as 1.29 × 10-14 and 4.29 × 10-14 M, respectively. As a result of the study, the developed MIP-based electrochemical sensor was suitable for detecting GAL with high specificity, selectivity, and sensitivity. Recovery studies were performed to determine the practical applicability of the sensor, and the results were satisfactory. This innovative sensor platform stands out as a reliable and sensitive analytical tool for determining GAL.

Recent advances in perovskite oxides for non-enzymatic electrochemical sensors: A review

Non-enzymatic electrochemical sensors with significant advantages of high sensitivity, long-term stability, and excellent reproducibility, are one promising technology to solve many challenges, such as the detection of toxic substances and viruses. Among various materials, perovskite oxides have become a promising candidate for use in non-enzymatic electrochemical sensors because of their low cost, flexible structure, and high intrinsic catalytic activity. A comprehensive overview of the recent advances in perovskite oxides for non-enzymatic electrochemical sensors is provided, which includes the synthesis methods of nanostructured perovskites and the electrocatalytic mechanisms of perovskite catalysts. The better sensing performance of perovskite oxides is mainly due to the lattice O vacancies and superoxide oxygen ions (O₂^2-/O^-), which are generated by the transfer of lattice oxygen to adsorbed -OH and have performed excellent properties suitable for electrooxidation of analytes. However, the limited electron transfer kinetics, stability, and selectivity of perovskite oxides alone make perovskite oxides far from ready for scientific development. Therefore, composites of perovskite oxides with other materials like graphitic carbon, metals, metal compounds, conducting organics, and biomolecules are summarized. Furthermore, a brief section describing the future challenges and the corresponding recommendation is presented in this review.

Electrochemical determination of acetaminophen at a carbon electrode modified in the presence of β-cyclodextrin: role of the activated glassy carbon and the electropolymerised β-cyclodextrin

Acetaminophen is a well-known drug commonly used to provide pain relief, but it can also lead to acute liver failure at high concentrations. Therefore, there is considerable interest in monitoring its concentrations. Sensitive and selective acetaminophen electrochemical sensors were designed by cycling a glassy carbon electrode (GCE) to high potentials in the presence of β-CD in a phosphate electrolyte, or by simply activating the GCE electrode in the phosphate solution. Using cyclic voltammetry, adsorption-like voltammograms were recorded. The acetaminophen oxidation product, N-acetyl benzoquinone imine, was protected from hydrolysis, and this was attributed to the adsorption of acetaminophen at the modified GCE. The rate constants for the oxidation of acetaminophen were estimated as 4.3 × 10–3 cm2 s–1 and 3.4 × 10–3 cm2 s–1 for the β-CD-modified and -activated electrodes, respectively. Using differential pulse voltammetry, the limit of detection was calculated as 9.7 × 10–8 M with a linear concentration range extending from 0.1 to 80 μM. Furthermore, good selectivity was achieved in the presence of caffeine, ascorbic acid and aspirin, enabling the determination of acetaminophen in a commercial tablet. Similar electrochemical data were obtained for both the β-CD-modified and activated GCE surfaces, suggesting that the enhanced detection of acetaminophen is connected mainly to the activation and oxidation of the GCE. Using SEM, EDX and FTIR, no evidence was obtained to indicate that the β-CD was electropolymerised at the GCE.

Green synthesis and characterization of DyMnO3-ZnO ceramic nanocomposites for the electrochemical ultratrace detection of atenolol

The present study is a first report about magnetic, optical and electrical as well as drug sensing properties of DyMnO₃-ZnO green-nanocomposites that are synthesized by Pechini modified method. Three natural compounds containing Vitis vinifera, Hibiscus sabdariffa and rhus juices are used as green and eco-friendly reagents for synthesis of the nanostructures. The nanostructures are characterized by various techniques containing Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray (EDX), field emission scanning electron microscopes (FESEM), high resolution transmission electron microscopy (HR-TEM), vibrating sample magnetometer (VSM) and diffuse reflectance spectroscopy (DRS). The calcination temperature, type of chelating agent and pH are optimized to achieve the best structural and smallest crystallite sizes of the systems via an eco-friendly approach. The studies show that the Vitis vinifera juice creates the best homogeneous sphere-like nanostructures. Therefore, the samples that are synthesized by Vitis vinifera juice are used for fabrication of a carbon paste electrode modified with DyMnO₃-ZnO nanocomposites (DMZN/CPE). The nanostructured modified electrode exhibits an excellent electrocatalytic effect for determination of atenolol (ATN) using voltammetry techniques. The results reveal that the DyMnO₃-ZnO green-nanocomposites have potential applications as a sensitive material in the drug analysis in biological samples.

Cu2+-BTC based metal–organic framework: a redox accessible and redox stable MOF for selective and sensitive electrochemical sensing of acetaminophen and dopamine

A Cu²⁺ plus benzenetricarboxylate (BTC) based ‘3D’ metal–organic framework HKUST-1 was synthesized via a facile microwave assisted route.

Applications of cobalt ferrite nanoparticles in biomedical nanotechnology

Magnetic nanoparticles (MNPs) are very attractive especially for biomedical applications, among which, iron oxide nanoparticles have received substantial attention in the past decade due to the elemental composition that makes them biocompatible and degradable. However recently, other magnetic nanomaterials such as spinel ferrites that can provide improved magnetic properties such as coercivity and anisotropy without compromising on inherent advantages of iron oxide nanoparticles are being researched for better applicability of MNPs. Among various spinel ferrites, cobalt ferrite (CoFe₂O₄) nanoparticles (NPs) are one of the most explored MNPs. Therefore, the intention of this article is to provide a comprehensive review of CoFe₂O₄ NPs and their inherent properties that make them exceptional candidates, different synthesis methods that influence their properties, and applications of CoFe₂O₄ NPs and their relevant applications that have been considered in biotechnology and bioengineering.

Investigation of magnetic and electrochemical sensing properties of novel Ba1/3Mn1/3Co1/3Fe2O4 nanoparticles

Novel Ba_1/3Mn_1/3Co_1/3Fe₂O₄ nanoparticles were successfully synthesized, characterized and investigated for their magnetic and electrochemical sensing properties.

Nanomaterial-based electrochemical sensing of neurological drugs and neurotransmitters

Nanomaterial-modified detection systems represent a chief driver towards the adoption of electrochemical methods, since nanomaterials enable functional tunability, ability to self-assemble, and novel electrical, optical and catalytic properties that emerge at this scale. This results in tremendous gains in terms of sensitivity, selectivity and versatility. We review the electrochemical methods and mechanisms that may be applied to the detection of neurological drugs. We focus on understanding how specific nano-sized modifiers may be applied to influence the electron transfer event to result in gains in sensitivity, selectivity and versatility of the detection system. This critical review is structured on the basis of the Anatomical Therapeutic Chemical (ATC) Classification System, specifically ATC Code N (neurotransmitters). Specific sections are dedicated to the widely used electrodes based on the carbon materials, supporting electrolytes, and on electrochemical detection paradigms for neurological drugs and neurotransmitters within the groups referred to as ATC codes N01 to N07. We finally discuss emerging trends and future challenges such as the development of strategies for simultaneous detection of multiple targets with high spatial and temporal resolutions, the integration of microfluidic strategies for selective and localized analyte pre-concentration, the real-time monitoring of neurotransmitter secretions from active cell cultures under electro- and chemotactic cues, aptamer-based biosensors, and the miniaturization of the sensing system for detection in small sample volumes and for enabling cost savings due to manufacturing scale-up. The Electronic Supporting Material (ESM) includes review articles dealing with the review topic in last 40 years, as well as key properties of the analytes, viz., pKa values, half-life of drugs and their electrochemical mechanisms. The ESM also defines analytical figures of merit of the drugs and neurotransmitters. The article contains 198 references in the main manuscript and 207 references in the Electronic Supporting Material. Figureᅟ

Facile and novel electrochemical preparation of a graphene-transition metal oxide nanocomposite for ultrasensitive electrochemical sensing of acetaminophen and phenacetin

A facile and novel preparation strategy based on electrochemical techniques for the fabrication of electrodeposited graphene (EGR) and zinc oxide (ZnO) nanocomposite was developed. The morphology and structure of the EGR-based nanocomposite were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (XPS) and Raman spectroscopy. Meanwhile, the electrochemical performance of the nanocomposite was demonstrated with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Due to the synergistic effect of EGR and ZnO nanoparticles, an ultrasensitive electrochemical sensor for acetaminophen (AC) and phenacetin (PCT) was successfully fabricated. The linearity ranged from 0.02 to 10 μM for AC and 0.06 to 10 μM for PCT with high sensitivities of 54,295.82 μA mM(-1) cm(2) for AC and 21,344.66 μA mM(-1) cm(2) for PCT, respectively. Moreover, the practical applicability was validated to be reliable and desirable in pharmaceutical detections. The excellent results showed the promise of the proposed preparation strategy of EGR-transition metal oxide nanocomposite in the field of electroanalytical chemistry.