Electrochemical Sensor Applications Research Articles

High performance and stable rGO/MoS2/NiMgS composite electrode for hybrid supercapacitor and electrochemical sensor applications

High performance and stable rGO/MoS2/NiMgS composite electrode for hybrid supercapacitor and electrochemical sensor applications

Electrospun polyvinyl alcohol/chitosan nanofibers modified with carbon nanotubes and sliver particles for electrochemical sensor application

Polyvinyl alcohol (PVA)/chitosan (CS) nanofibers modified with carbon nanotubes (CNT) and silver (Ag) particles are electrospun onto a graphite plate (GP) substrate to form the PVA-CS-CNT-Ag/GP electrode for electrochemical sensor application. Microstructure characterization demonstrates that PVA-CS nanofibers exhibit a loose and porous network structure, significantly improving the effective reaction surface area. Electrochemical measurements show the PVA-CS-CNT-Ag/GP electrode exhibits the limit of detection of 23.2 μM, the linear range of 65–176,460 μM and the sensitivity of 3.3945 μA cm−2 mM−1. Anti-interference test results show that the sensor has high selectivity towards H2O2. Stability test results indicate that the sensor exhibits good stability, as evidenced by the response current of 83.94 % after a period of 30 days. Simulation calculations indicate that PVA-CS-CNT-Ag exhibits lower interfacial energy (−2.3293 eV) compared to PVA-CS-CNT (−0.3674 eV) and PVA-CS-Ag (−0.7646 eV), smaller band gap (0.318 eV) compared to PVA-CS (3.640 eV), higher density of states at Fermi level (14.7332 electrons/eV) than others. Experimental measurements and simulation calculations indicate that PVA-CS-CNT-Ag electrospun nanofibers exhibit promising potential as an electroactive material for the electrochemical detection of H2O2.

Artificial intelligence-aided electrochemical sensors for capturing and analyzing fingerprint profiles of medicinal materials

This study explores the application of artificial intelligence-aided electrochemical sensors for authenticating medicinal materials, focusing on sika deer antler cap powder. Utilizing differential pulse voltammetry and graphene-modified screen-printed electrodes, we developed a novel method to capture unique electrochemical fingerprints of authentic, counterfeit, and adulterated samples. Three machine learning models—Support Vector Machine (SVM), Random Forest (RF), and Extreme Learning Machine (ELM)—were evaluated using both full voltammogram and principal component analysis (PCA) reduced features. The SVM model with PCA-reduced features emerged as the optimal approach, achieving a classification accuracy of 97.9 % while reducing training time by 65.6 % (from 3.2 s to 1.1 s) and prediction time by 71.4 % (from 0.07 s to 0.02 s per sample) compared to using full voltammogram features. This reduction in computational complexity was achieved by decreasing the input dimensionality from 601 to 5 features through PCA, while maintaining high classification performance across all sample categories. This model demonstrated high sensitivity (>97 %) and specificity (>98 %) across all sample categories, with a notably low limit of detection for adulteration at 2.8 %. Characteristic peaks, such as the pantocrin peak at 0.25 V for authentic samples, provided a robust basis for differentiation. The method's effectiveness in detecting subtle adulterations was evidenced by its ability to identify samples with as low as 5 % adulteration. Furthermore, the approach showed excellent generalization, maintaining 97.0 % accuracy on an independent validation set. These findings highlight the potential of this technique for rapid, accurate, and cost-effective authentication of medicinal materials, addressing the growing challenge of counterfeit products in the pharmaceutical industry.

Influence of Zr on the Sun-light driven photocatalytic activity, electrochemical sensor, and microbial applications of CuFe 2 O 4 NPs

Influence of Zr on the Sun-light driven photocatalytic activity, electrochemical sensor, and microbial applications of CuFe ₂ O ₄ NPs

Electrochemical behavior and L-tyrosine sensing properties of nanostructured Cr, Sn and La-doped α-Fe2O3 interfaces

L-tyrosine (Tyr) is a promising biomarker for the diagnosis and monitoring of metabolic disorders and neurodegenerative diseases. This study reports on the electrochemical properties of α-Fe2O3 nanostructures doped with Cr, Sn and La, referred to as CrFeOx, SnFeOx and LaFeOx, respectively, and their application in the enzyme-free electrochemical Tyr sensors. These disposable sensors offer accurate Tyr concentration analysis at room temperature, addressing the limitations of current point-of-care diagnostic methods. The CrFeOx, SnFeOx, and LaFeOx nanostructures serve as selective agents for binding and recognizing Tyr, deposited onto disposable graphite pencil electrodes to form the electrochemical interface. The interfacial resistance, charge-transfer kinetics, mechanism, and reversibility are studied via extensive electrochemical measurements employing electro¬chemical impedance spectroscopy and cyclic voltammetry. Furthermore, differen¬tial pulse voltammetry demonstrates excellent Tyr sensing performance in the concen¬tration range of 0 to 80 μM with 2.65 µA µM-1 cm-2 sensitivity and 360 nM thres¬hold detection limit for the best-performing CrFeOx sensors. Hence, these α-Fe2O3-based sensor systems are practical and efficient for selective Tyr detection, offering potential advancements in personalized healthcare and early disease diagnosis.

Portable unibody semi-flow injection voltammetric sensor for on-site screening of illegal additive sibutramine in food supplements

In this study, a simple, portable, unibody semi-flow injection system was coupled with a screen-printed electrode (SFI/SPE) for the on-site electrochemical screening of sibutramine (SBM) in food supplements. The SFI was fabricated by laser engraving acrylic plastic and was attached to a modified SPE with double-sided adhesive tape. The SPE was modified with a nanocomposite of nitrogen-doped graphene nanoflakes and carbon nanotubes synthesized using hydrothermal and ultrasonic methods. The morphological structure and electrochemical properties of the nanocomposite were thoroughly investigated. The portable SFI-SPE sensing system was designed to be interfaced with a smartphone. Sample solutions can be continuously injected into the sensing system using a plastic syringe and SBM is determined by square wave anodic stripping voltammetry, controlled by means of a smartphone. The developed sensing system displayed linear ranges from 0.010 to 10 μg mL⁻1 and 10–60 μg mL⁻1 with an LOD of 0.0035 μg mL⁻1. The sensor delivered a response in a short time and demonstrated not only good reproducibility (RSDs ranging from 2.9 % to 4.9 % (n = 10)) and excellent resistance to interference but also high accuracy. The developed sensor was utilized for the screening and quantification of SBM in food supplements but the system could be used in a wider range of electrochemical (bio) sensor applications in the future.

Electrochemical Sensors in the Food Sector: A Review.

In a world that is becoming increasingly concerned with health, safety, and the sustainability of food supply chains, the control and assurance of food quality have become of utmost importance. This review examines the application and potential of electrochemical sensors in the dynamic field of food science to meet these expanding demands. The article introduces electrochemical sensors and describes their operational mechanics and the components contributing to their function. A summary of the most prevalent electrochemical methods outlines the diverse food analysis techniques available. The review shifts to discussing the food science applications of these sensors, highlighting their crucial role in detecting compounds in food samples like meat, fish, juice, and milk for contemporary quality control. This paper showcases electrochemical sensors' utility in food analysis, underscoring their significance as powerful, efficient tools for maintaining food safety and how they could transform our approach to global food quality control and assurance.

Synthesis of Co/Co3O4 Heterostructure in N-Doped Porous, Amorphous Carbon: A Superior Electrochemical Sensor for Sensitive Determination of Alectinib in Various Fluids.

Highly crystallized Co and Co3O4 nanoparticles embedded in an N-doped amorphous carbon matrix have been successfully fabricated by the molten-salt-assisted method using KClO3 and zeolitic imidazolate framework-12 (ZIF-12). Pyrolysis of ZIF-12 with different concentrations of KClO3 leads to embedded Co and Co3O4 nanoparticles in a conductive amorphous carbon network. The impact of salt concentration on the morphology and electrochemical performance of these composites was investigated for electrochemical sensor applications. By employing a straightforward and efficient technique, Co/Co3O4 heterostructures were successfully synthesized in N-doped porous amorphous carbon. The Co/Co3O4 carbon heterostructures were optimized by varying the salt concentration, resulting in a significant electrochemical sensor performance for detecting ALC in both bulk and biological fluids. The sensor demonstrates excellent sensitivity (62.97 nmol/L) and selectivity toward ALC, with a wide linear range (0.2-2 μM) and a low detection limit (18.89 nM). Furthermore, it displays remarkable stability and reproducibility, positioning it as a strong contender for practical use in pharmaceutical analysis and biomedical research. This study presents a significant advancement in electrochemical sensing technology and underscores the potential of Co/Co3O4 heterostructures in the development of high-performance sensors for detecting bioactive compounds in complex matrices.

Electrochemical characterization of carbon black in different redox probes and their application in electrochemical sensing

Carbon black - materials rich in carbon nanostructures - have been successfully applied as modifiers of electrochemical transducers, rivalling other carbon nanomaterials for cost and ease-of-use. Despite the remarkable promise of this nanomaterial, no study has yet comparatively characterised a wide range of different grades of carbon black for their utility in electrochemical sensors. Here, we explore several commonly-studied carbon black grades (N220, N234, N326, N330, N339, N375, N550, N660 and Lamp Black-101), alongside relatively newer grades (Printex®-200, Printex® G, Printex® XE-2B, and Printex® Zeta) for their application in electrochemical sensors. The effects of coating glassy carbon electrodes with carbon black on electrode performance were studied by cyclic voltammetry using three redox probes: ferri-/ferrocyanide (anionic probe molecules), ferrocenemethanol (neutral) and hexaammineruthenium (cationic). Raman Spectroscopy characterisation of the different grades associated a lower degree of graphitisation with superior electrode modifiers. Generally, modification increased the anodic peak current for ferri-/ferrocyanide probes; and lowered anodic potential for ferri-/ferrocyanide and hexaammineruthenium probes. Increases in peak current and potential observed at ferrocenemethanol are consistent with the increased tendency for this probe to adsorb to the surface of modified electrodes. N330 and Printex® XE-2B displayed the best electrocatalytic properties in terms of enhanced peak currents and lowered anodic overpotentials for the redox probes. CB grades were used to modify screen-printed carbon electrodes and the obtained sensors examined for anodic detection of reduced nicotinamide adenine dinucleotide (NADH) cofactor by cyclic voltammetry. Printex® XE-2B significantly improved the detection of NADH and was further used for chronoamperometric detection of NADH at low overpotentials. Grades N220, N375, N550 and P-G showed their suitability as enzyme scaffolds for sensor fabrication, as determined by their preservation of the activity of a NAD-dependent aldehyde dehydrogenase.

Portable self-powered electrochemical aptasensor for ultrasensitive and real-time detection of microcystin-RR based on hydrovoltaic-photothermal coupling effect

Coupling different energy harvesting technologies to obtain an excellent output signal is essential for the development of high-performance self-powered electrochemical sensors. Herein, a novel hydrovoltaic-photothermal coupling self-powered electrochemical aptasensing platform was designed for sensitive detection of microcystin (MC-RR) with a digital multimeter as a direct visual readout strategy. The straightforward ultrasonic method was employed to synthesize polyaniline (PANI) and bismuth oxybromide (BiOBr) nanosheets, which were then integrated as active components in a hydrovoltaic device. The unique layer structure of two-dimensional (2D) nanomaterials BiOBr can create flexible interlayer spaces to accommodate various ions and water molecules, which was beneficial to construct evaporation-driven channels. Meanwhile, the exceptional photothermal characteristics of polyaniline could accelerate the water evaporation rate, consequently boosting the migration speed of charge carriers and increasing output signal. Moreover, a digital multimeter was connected to the constructed sensor for real-time displaying the output signal. With the assistance of aptamer, a novel self-powered electrochemical aptasensing platform was constructed for sensitive detection of MC-RR. Under optimum conditions, the output signal of the hydrovoltaic-photothermal coupling cell was linearly related to the logarithm of MC-RR concentration in the range of 1 fM to 1 nM with a detection limit of 0.31 fM (S/N = 3). Furthermore, this sensor also exhibited many advantages such as high selectivity, good repeatability and portability. Such novel strategy not only offers a completely new general approach to construct high-performance self-powered devices for the detection of MC-RR, but also provides a new strategy for advancing the miniaturization and field application of self-powered electrochemical sensors.

A wide linear range and highly sensitive electrochemical reduction of environmental hazard (p-Nitrotoluene) using carbon-based hybrid composite (Ti3C2TX@MnCo2O4)

The electrochemical sensor is receiving much attention because of the evolving on-time sensing technology. It is crucial to develop new catalysts for electrochemical sensor applications with favorable physicochemical, electrocatalytic properties and good conductivity to meet the demands of on-time monitoring applications. The excellence of this research work is the preparation of Ti3C2TX@MCO nanocomposite by ultra-sonication method for the sensing of p-Nitrotoluene (p-NT). The prepared electrode material exhibits excellent electrocatalytic properties towards the sensing of p-NT compared with other electrodes. The p-NT was quantified by Differential Pulse Voltammetry (DPV) and Amperometric (i-t) techniques. The good linear range was observed by DPV (3–1860 μM) and i-t method (0.18 – 4170 μM). The calculated limit of detection (LOD) from DPV and i-t methods are 93.5 and 35.1 nM, respectively. The sensitivity values calculated from DPV, and i-t methods are 1.68 µA/µM. cm2 and 1.71 µA/µM. cm2, respectively. The proposed sensor system exhibits better selectivity, reproducibility, repeatability and stability for sensing of p-NT. A real time p-NT detection study was conducted using environmental water samples.

Superior Electrochemical Sensor Application of Co3O4/C Heterostructure in Rapid Analysis of Anticancer Drug Palbociclib in Pharmaceutical Formulations and Biological Fluids.

In this work, we report a study examining how different salt concentrations affect the structure and electrochemical performance of two Co3O4/C materials designed for the fabrication of an easy, cheap, fast, safe, and useful electrochemical sensor for the detection of Palbociclib (PLB). Co3O4 nanoparticles were successfully created by encapsulating them in N-doped amorphous carbon matrices by using the molten salt-assisted approach. In this process, different amounts of potassium iodate and zeolitic imidazolate framework-12 (ZIF-12) were used, followed by pyrolysis at 800 °C. Optimum Co3O4 embedded porous carbon structures were obtained, and the composite with the highest electrochemical properties was modified to a glassy carbon electrode (GCE) surface for PLB detection. The linear response spanned from 1.0 to 5.0 μM, featuring a limit of detection (LOD) of 0.122 μM and a limit of quantification (LOQ) of 0.408 μM; the correlation coefficient was calculated as 0.995. The high sensitivity of the method in detecting PLB in pharmaceutical samples and human urine demonstrated its feasibility, with recovery percentages ranging from 99.3% to 101.3% and relative standard deviation (RSD) values of <3%. Therefore, this technique will make a significant contribution to monitoring and improving existing cancer treatment options.

Electrodeposited ZnO Nanostructures on ITO Surfaces: Exploring Their Efficacy for Cholesterol Biosensing Applications

In this study, ZnO nanostructures were prepared by electrochemical anodization of electrodeposited Zn on ITO/glass substrates for cholesterol detection. The efficiency of the developed ZnO nanostructures in the detection of the Cholesterol oxidase (ChOx) enzyme was determined by the cyclic voltammetry method. The XRD and SEM results confirmed the synthesis of ZnO nanostructures prepared by the anodization method with various parameters. The effect of electrodeposition and anodization time on the morphology was observed. Cyclic voltammetry of ZnO/Zn/ITO/glass and Pt/ZnO/Zn/ITO/glass electrodes in electrolytes with various cholesterol concentrations was performed. The detection limit of the obtained Pt/ZnO/Zn/ITO/glass structured electrode was calculated as 0.965x10-3M. The resulting material with a layered structure may have potential applications in electrochemical sensors and biosensors in biomedical applications. In addition to biosensing performance, this study proposes a new approach for the development of ZnO-based biosensors that does not require expensive infrastructure and raw material costs, making it possible to develop high-sensitivity biosensor electrodes with lower detection limits with improvements to be made in future studies.

Dual electrochemical detection of leucovorin and its metabolite 5-methyltetrahydrofolic acid

Current healthcare trends focus on personalised precision medicine, which customises treatment based on individual responses to both diseases and therapeutic interventions. This marks a departure from a “one size fits all” approach towards a more sophisticated strategy. However, notwithstanding progress in the theoretical knowledge for personalised precision approaches, resource constraints impede their implementation. Monitoring drug therapies is vital for the advancement of precision medicine, alongside drug development and targeted treatment strategies. This study presents the potential of electrochemical approaches including square wave voltammetry (SWV) as a proof-of-concept for the simultaneous monitoring of circulating concentrations of 5-methyltetrahydrofolate (5-MTHF) and leucovorin calcium (LV) within biological matrices. An easy-to-use and portable sensor has been developed for the detection of 5-MTHF and LV at therapeutically relevant concentrations without prior sample preparation. The sensor was successfully tested in artificial urine and human pooled serum, demonstrating its efficacy in diverse biological matrices. This approach successfully illustrated the dual detection of LV and 5-MTHF over the linear range 0 to 10 µM which is within the therapeutically relevant range for both within urine. The developed sensor exemplifies the potential of electrochemical sensors as point-of-care devices. Its rapid time to result and elimination of time-consuming sample preparation improve usability for clinicians, broadening the application of electrochemical sensors in clinical settings. This dual monitoring approach offers significant contributions to the evolution of precision medicine by providing real-time, accurate drug monitoring capabilities.

Application of Electrospun Nanofiber-Based Electrochemical Sensors in Food Safety.

Food safety significantly impacts public health and social welfare. Recently, issues such as heavy metal ions, drug residues, food additives, and microbial contamination in food have become increasingly prominent. Electrochemical sensing technology, known for its low cost, simplicity, rapid response, high sensitivity, and excellent selectivity, has been crucial in food safety detection. Electrospun nanofibers, with their high specific surface area, superior mechanical properties, and design flexibility, offer new insights and technical platforms for developing electrochemical sensors. This study introduces the fundamental principles, classifications, and detection mechanisms of electrochemical sensors, along with the principles and classifications of electrospinning technology. The applications of electrospun nanofiber-based electrochemical sensors in food safety detection over the past five years are detailed, and the limitations and future research prospects are discussed. Continuous innovation and optimization are expected to make electrospun nanofiber-based electrochemical sensors a key technology in rapid food safety detection, providing valuable references for expanding their application and advancing food safety detection methods.

Preparation and application of boron and fluorine co-doped rGO electrochemical sensor

N, NF, and NS-doped reduced graphene oxide(rGO) are used for the detection of dopamine (DA), however, the sensitivity and linear detection range still need to be improved. In this paper, BF-doped reduced graphene oxide (BFrGO) synthesized by hydrothermal method using fluoroboric acid as boron and fluorine sources used for the efficient detection of DA. The electrochemical detection results under the optimal buffer solution pH = 3.4 showed that the sensitivity of its detection of DA is as high as 0.804 μA/μM, the linear detection range is in the range of 5–100 μM, and the detection limit is 0.98 μM. XPS showed the formation of BC3, BC2O, BCO2, C–F half-ionic and C–F ionic bonds. DFT calculations show that B doping of rGO provides active sites and enhances its electrical conductivity. and F doping of rGO introduces new electrically active sites and improves the charge transfer ability. The synergistic effect of BF provides more active sites and enhances the charge transfer ability and adsorption energy. The BFrGO as an electrochemical sensor will provide new research directions.

Monitoring the Corrosion Resistance of Cold-Spray Coatings with Membrane-Based Sensors

Ensuring the management of gas transportation infrastructure requires the monitoring of internal corrosion within pipelines. The utilization of membrane-based electrochemical sensors is a promising advancement in corrosion risk monitoring. These sensors demonstrate an ability to operate within humidified gas environments, previously inaccessible to conventional electrochemical monitoring methods. Simultaneously, ongoing research is delving into novel sacrificial coatings and application methods to prolong the lifespan of existing pipeline structures and minimize associated repair costs. In this context, we broaden the application of membrane-based electrochemical sensors to investigate the response of electrodes equipped with cold-spray coatings. This examination encompasses a range of fluids exhibiting varying levels of corrosivity pertinent to natural gas pipelines. Multiple sensors with 316 stainless steel working electrodes were coated with cold spray sacrificial coating then exposed to humidified gases with differing relative humidities (RH) (5 %, 50 %, and 95 %) and condensed phases with differing salt content (deionized water and 0.1 mol kg-1 NaCl solution). Three electrochemical techniques (potentiometry, impedance spectroscopy and potentiodynamic scans) were used to monitor the corrosive environment and probe the extent of coating coverage. For the conditions studied, impedance values were extremely sensitive to changes in water content through changes in the membrane resistance (from ~1 kΩ in deionized water to ~5 MΩ with 5 % RH). Polarization resistances (Rp) consistently decreased with increasing corrosivity (~3 kΩ in deionized water to 15 GΩ with 5 % RH). Scanning electron microscopy and energy dispersive X-ray spectroscopy were used to identify the extent to which corrosion products permeated the membrane after major corrosion events.

A Metallo‐ Silsesquioxane Synthesized from Cu (II) via a Cyanide Fe (III) Bridge: Synthesis and Application as an Electrochemical Sensor

AbstractA new metallohybrid silsesquioxane (S) was synthesized herein from copper and ferricyanide via a cyanide bridge to produce a new electroactive hybrid material (SCuH), which was then characterized by spectroscopic and microscopic techniques and cyclic voltammetry. The voltammetric behavior of SCuH employing a graphite paste electrode indicates a well‐defined redox couple with formal potential Eθ′=0.76±0.01 V. The electrode exhibited high sensitivity to nitrite and was successfully tested for nitrite detection. The linearity of the analytical curve was 2.0×10−4 mol L−1 − 1.0×10−3 mol L−1, with a limit of detection of 2.65×10−5 mol L−1, and sensitivity amperometric value of 57.63 mA/mol L−1. These findings suggest that this material displays exceptional potential for application in electrochemical sensors designed for nitrite detection.

Chitosan Nanocomposites-Based Electrochemical Sensors: A Review

Chitosan nanocomposites represent a promising class of materials formed by combining chitosan with various nanomaterials. This innovative approach leverages the advantageous properties of both chitosan—a biopolymer known for its biocompatibility, natural abundance, high film-formability, and tunable functionality—and nanomaterials, which exhibit enhanced properties such as high surface area, electrical conductivity, and catalytic activity. While chitosan alone is limited by its low electrical conductivity and mechanical strength, its integration with nanomaterials addresses these shortcomings, enhancing its utility in electrochemical sensing applications. This review comprehensively summarizes recent advancements in chitosan-based nanocomposites, mainly focusing on their application in electrochemical sensors. It discusses the various nanocomposites combined with metals, metal oxides, carbon-based materials, and other nanostructures. The review highlights the synthesis methods, performance metrics, and potential applications of these sensors across fields such as environmental monitoring, food safety, medical diagnostics, and pharmaceuticals. Emphasis is placed on the advancements over the past five years, with a discussion on the significant impact these sensors have had in detecting critical analytes like heavy metals, neurotransmitters, glucose, and reactive oxygen species.

Unveiling the effect of Bi in ZnFe2O4 nanoparticles in electrochemical sensors

This work investigates the effect of the inclusion of Bi3+ ions in ZnFe2O4 nanoparticles on electron transfer at the electrochemical interface. ZnBixFe2-xO4 (x = 0, 0.5, 1, 2) nanomaterials are synthesized and the impact of Bi3+ ions on the chemical features of ZnFe2O4 nanoparticles is studied by using different materials’ characterization techniques. The effect of the change in the chemical composition of ZnFe2O4 nanoparticles on the electrochemical sensing performance is extensively studied and correlated with the electrochemical sensitivity and kinetic rate constant. Screen-printed electrodes functionalized with ZnBixFe2-xO4 nanomaterials have an excellent enhancement of electrochemical sensing performance towards paracetamol, as a test molecule, compared to the carbon electrodes. The highest sensitivity (37.8 ± 0.2 μA/mM) and the best kinetic rate constant (13.1 ± 2.8 ms−1) are achieved by the ZnFe2O4 sensor, while the ZnBi2O4 sensor achieved a sensitivity of (23.5 ± 0.6) μA/mM with a kinetic rate constant of (0.45 ± 0.16) ms−1. The ZnFe2O4 sensor is found to have a direct electron transfer, whereas the other sensors participate in a surface state-mediated electron transfer at the electrochemical interface. This research shows a clear path to the potential applications of spinel oxide-based electrochemical sensors for specific drugs or molecules detection.