Sensitive Electrochemical Sensor Research Articles

Synthesis of BiDy composite oxide nanoflakes with good electrochemical properties

BiDy composite oxide nanoflakes with the thickness of about 50 nm were synthesized by one-step hydrothermal method. The electrodes modified with BiDy composite oxide nanoflakes exhibit superior electrochemical behavior for detecting L-cysteine using cyclic voltammetry (CV) method. The impact of scan rate, electrolyte, and concentration of L-cysteine for electrochemical behaviors were investigated. A pair of strong quasi-reversible CV peaks are observed at +0.03 V (cvp1) and –0.69 V (cvp1′) with peak current of 171.2 μA and 171.3 μA, respectively for the BiDy composite oxide nanoflake-modified GCE in 0.1 M KCl and 2 mM L-cysteine solution. GCE modified with the BiDy composite oxide nanoflakes displays broad range of linearity (0.001-2 mM) and low detection limit (0.29 μM) for L-cysteine. Using a hydrothermal approach as a synthesis technique for nanoflakes, as well as a facile and sensitive electro-chemical sensor based the nanoflakes was developed to detect L-cysteine, makes it a promising approach for practical application.

An antifouling electrochemical aptasensor based on a Y-shaped peptide for tetracycline detection in milk

Nonspecific adsorption of non-target components (especially proteins) in food matrix on sensing surfaces deteriorates accuracy and sensitivity of electrochemical sensors, which is a key challenge for food safety sensing. Therefore, electrochemical sensors with antifouling capability of high-protein food matrices are highly desired. In this paper, an efficient and simple antifouling electrochemical aptasensor for tetracycline (TC) analysis was constructed based on a self-designed Y-shaped peptide [CPPPPEK-(RSERSERSE)2] consisting of cysteine as the anchoring segment, polyproline as the supporting segment, and -EK-(RSERSERSE)2 as antifouling branches. Hydrophilic and electrically neutral amino acid sequence and Y-shaped space structure of the peptide endow the sensing surface with good antifouling performance in protein solutions and diluted milk. Under optimized experiment conditions, the proposed aptasensor can detect TC with a wide linear range (0.01–100 ng mL−1) and a limit of detection of 5.3 pg mL−1 (S/N = 3). The spiked recovery experiments confirmed high accuracy of the aptasensor in diluted milk without other pretreatments (recoveries: 90.96%–95.86%). This strategy offers a valid way to reduce matrix interference, showing a promise to be extended to other sensing systems for different targets.

Highly sensitive rhodamine B dye-based electrochemical sensor for lactose detection

Lactose (LAC) is the main disaccharide sugar found in milk and dairy products, making it easily accessible as a food source. In addition to its importance for human and animal health, LAC concentrations serve as a biomarker of milk quality. In this study, we reported the detection of LAC using a highly sensitive electrochemical sensor based on rhodamine B (RhB) dye. The prepared RhB-based sensor exhibited excellent characteristics, including a straightforward manufacturing technique, cost-effectiveness, and exceptional sensitivity. We conducted a comparative analysis of the electrochemical response of the novel RhB-based sensor, evaluating its electrochemical performance across varying LAC concentrations and when different analyte materials (glucose, fructose, and maltose) were employed. The proposed analytical method was utilized to determine LAC using an electrochemical RhB-based sensor under optimal experimental conditions. As a result, it was experimentally observed that high sensor sensitivity of RhB based sensor against LAC was inversely proportional to the impedance value and directly proportional to conductance which corolated with the transport mechanism of RhB.

Two-dimensional titanium carbide MXene embedded in exfoliated graphite nanoplatelets for voltammetric sensing of thiamethoxam in beekeeping products

To prepare a novel and highly sensitive electrochemical sensor for determination of Thiamethoxam (a neonicotinoid insecticide), a nanohybrid material was utilized based on two-dimensional titanium carbide (Ti3C2Tx), belonging to the MXenes class, and exfoliated graphite nanoplatelets. The resulting material was characterized with different techniques, such UV-Vis, XRD, SEM, TEM and XPS. The sensor displayed a remarkable improvement in current responses for the electrochemical reduction of thiamethoxam compared to the bare glassy carbon electrode. Under optimized conditions, a calibration curve was built by differential pulse voltammetry in the range of 0.048 to 30 µmol L−1 with limit of detection of 20 nmol L−1. Recovery data from 90 to 105% were obtained in beekeeping samples using the proposed sensor. Additionally, the sensor presented accurate and precise data when compared to chromatographic method data, and it was validated with statistical tests.

Fabrication of Highly Sensitive Electrochemical Sensor Based on Chromium-Doped Ferrite Nanoparticles: Hybrid Graphene Nanosheets for the First Voltammetric Determination of Asenapine Maleate in Formulations and Human Plasma

Ferrite nanoparticles are interesting materials given their unique physical and chemical properties and wide applications. A novel electrochemical sensor based on a series of chromium-nano-ferrites {Fe3+[Fe2+Fe3+ (1-x)Cr3+ x ]O4; x (0.0–1.0} was fabricated for determination of Asenapine maleate (ASE.M). X-ray diffraction revealed the formation of crystallite nano-particles of lattice constant of (8.299–8.345 Å) with a single phase of cubic inverse spinel structures. Particle size and specific surface area were (9.10–27.60 nm) and (60–175 m2g−1) using Transmission electron microscopy and Brunnauer-Emmett-Teller (BET) analysis, respectively. Among this Cr x Fe(3−x)O4 series, (CrFe2O4; x = 1) was appeared to get the smallest particles size and highest BET surface area. The charge transfer resistance (RCT) of (2220, 1680, 765, and 490 Ω) were achieved for Cr x Fe(3−x)O4 NPs/CPE (x = 0.0, 0.4, 0.8, and 1.0), respectively. CrFe2O4 performance was then improved via incorporation of 2D-graphene atomic crystals in a new ferrite-graphene nanocomposite of [0.25%(w/w) CrFe2O4 NPs: 7%(w/w) graphene nanosheets]. The feasibility of this sensor is achieved for determination of ASE.M in brand Saphris® and local Asenapine pharmaceutical products. In addition, a wide linear concentration range of (6.5 × 10−9–1.0 × 10−6 M) with LOD value of 8.88 × 10−10 M were achieved in human plasma.

Electrochemical determination of theophylline using a nickel ferrite/activated carbon-modified electrode

In this work, a nanocomposite based on nickel ferrite/activated carbon (NiF/AC) was used to modify a highly sensitive electrochemical sensor for the quantification of theophylline (TPL) in pharmaceutical tablets. The synthesized materials were characterized using x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive x-ray spectroscopy-elemental mapping and surface area analysis via the Brunauer–Emmett–Teller method. Cyclic voltammetry was employed to study the electrocatalytic properties of the NiF/AC-GCE toward the oxidation of TPL. The dependence of the electrochemical response on the scan rate and pH was also investigated, and the working parameters were optimized. The linear range of the established electrochemical biosensor was from 0.5 to 5 μM (R2 = 0.997), with a detection limit of 0.21 μM. The present method was tested using three pharmaceutical formulation standard samples with good accuracy and acceptable recovery. Thus, it is a promising candidate for the determination of TPL in pharmaceutical formulations.

One-pot synthesis and hydrogen peroxide electrochemical sensing of 3D TiO2/MnO2 nanorods assembled microspheres.

Nanorods assembled 3D microspheres of TiO2/MnO2 were prepared via a simple one-pot hydrothermal approach. The resultant composite material exhibited remarkable electrocatalytic activity for hydrogen peroxide (H2O2) in comparison to each single component. The electrochemical sensor constructed with TiO2/MnO2 exhibited a linear relationship within the range 0.0001-5.6 mmol·L-1 for H2O2. The limit of detection (LOD) and sensitivity for H2O2 were 0.03 µmol·L-1 (S/N = 3) and 316.6 µA (mmol·L-1)-1cm-2. Moreover, this sensor can be employed to detect trace amount of H2O2 in serum and urine samples successfully, supporting an insight and strategy for a more sensitive electrochemical sensor.

Development of a highly sensitive electrochemical sensor for dexamethasone detection using Fe3O4/polyaniline-Cu(II) microspheres and hematite nanoparticles

Dexamethasone, a potent synthetic glucocorticoid, is widely used for its anti-inflammatory and immunosuppressive properties. However, its misuse as a performance-enhancing drug in sports has raised concerns among regulatory authorities. To address this issue, an electrochemical sensor based on Fe3O4/polyaniline (PANI)-Cu(II) microspheres and hematite nanoparticles was developed for the sensitive and selective detection of dexamethasone. The sensor exhibited excellent electrocatalytic activity towards the oxidation of dexamethasone due to the synergistic effect of the high conductivity and large surface area of the Fe3O4/PANI composite microspheres, the electrocatalytic properties of the loaded copper(II) ions, and the enhanced electron transfer of the hematite nanoparticles. Under optimized conditions, the sensor showed a wide linear range of 0.05–50 μM, with a detection limit of 0.015 μM. The sensor also demonstrated good selectivity, reproducibility (RSD = 3.2 %, n = 5), and long-term stability (92 % retention after 4 weeks). Furthermore, the sensor was successfully applied for the determination of dexamethasone in spiked human serum and urine samples, with recoveries ranging from 97.5 % to 103.5 % and RSDs less than 3.5 %.

A highly sensitive electrochemical sensor for the detection of chloramphenicol based on Ni/Co bimetallic metal-organic frameworks/reduced graphene oxide composites

A highly and simply sensitive electrochemical sensor has been developed for the detection of trace chloramphenicol (CAP) in water based on Ni/Co bimetallic metal–organic frameworks-reduced graphene oxide composites [rGO/NiCo-BTC MOFs (BTC = 1,3,5-benzenetricarboxylicacid)] modified glassy carbon electrode (GCE/rGO/NiCo-BTC MOFs). The bare glassy carbon electrode was initially coated with graphene oxide (GO). Subsequently, the GO was electrochemically reduced to obtain reduced graphene oxide (rGO). NiCo-BTC MOFs was grown on the surface of rGO modified electrode by in-situ electrochemical synthesis method to construct GCE/rGO/NiCo-BTC MOFs. The as-made composites films have been characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. Further, different electrochemical techniques were utilized for investigating the electrochemical reduction behaviors of CAP at GCE/rGO/NiCo-BTC MOFs. This composites film modified electrode combines the large surface area and excellent electrical properties of rGO with the good catalytic activity of NiCo-BTC MOFs, resulting in a significant enhancement of the electrochemical signal during the electroreduction of CAP. Under the optimized experimental conditions, the sensor exhibits excellent sensing performance for CAP, with a wider linear dynamic range (0.1 − 100 μM), a lower limit of detection (0.235 μM) (S/N = 3) and a ultra-high sensitivity (33.12 μA·μM−1·cm−2). The tap water spiked with different concentrations of CAP were considered. The recoveries range from 97.79 % to 100.07 %, with relative standard deviations ranging from 3.45 % to 5.40 %. The method has been successfully applied for the determination of CAP in real samples, yielding satisfactory results. With further research and development, electrochemical in-situ synthesis of MOFs composites have the potential to revolutionize the design and performance of electrochemical sensors, holding great promise in the field of electrochemical sensing.

A sensitive electrochemical sensor based on Fe3O4 magnetic nanoparticles/chitosan/graphene composite for detection of Pb2+ in aqueous solutions

A sensitive electrochemical sensor based on Fe3O4 magnetic nanoparticles/chitosan/graphene composite for detection of Pb2+ in aqueous solutions

Simple, low-cost and sensitive voltammetric detection of homocysteine by using nanocarbon black as electrode material

Generally, the elevated homocysteine (Hcys) degree is easy to cause various diseases, so it is very important to develop suitable method for its quantitative monitoring Because from the unique superiorities (e.g., rapid reaction time and high sensitivity) of the electrochemical technology, several voltammetric sensors have been reported for Hcys detection, but designing more simple, low-cost and sensitive electrochemical sensor for Hcys is still very significant. In this work, just by using a considerable low-cost and readily-accessible nanomaterial, nanocarbon black (CB), as electrode material to detect Hcys for the first time, a very simple, low-cost and sensitive electrochemical sensor for Hcys is fabricated successfully based on CB modify electrode. Via optimizing several key parameters including dropped amount of CB dispersion, preconcentration time of Hcys and pH value of phosphate buffer solution, the as-designed sensor exhibits excellent detection capability coupled with low detection limit (0.003 μM) and wide linearity (0.01–15.0 μM). Furthermore, the repeatability, long-term stability and selectivity as well as real application performances were also evaluated, revealing satisfactory results.

Facile synthesis of PEDOT@rGO nanocomposites for novel electrochemical sensor for the determination of 4-chlorophenol in a real water sample

A sensitive electrochemical sensor was developed for the detection of 4-chlorophenol (4-CP) using the nanocomposite based on poly (3,4-ethylenedioxythiophene) and reduced graphene oxide (PEDOT-rGO). The GC electrode modified with the proposed nanocomposite was characterized using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and electrochemical impedance spectroscopy. The Raman analysis confirmed the successful incorporation of PEDOT onto the reduced graphene oxide (rGO) surface. It is also observed in the SEM analysis that PEDOT nanoparticles were spread over the rGO sheet. The lower charge transfer resistance (Rct) values for PEDOT-rGO/GCE compared to PEDOT/GCE in electrochemical impedance spectroscopy confirms the unique conducting properties of rGO and the higher surface area of PEDOT in the proposed composite on the GCE surface. The cyclic voltammetric and differential pulse voltammetric (DPV) results has indicated that the PEDOT-rGO-modified glassy carbon electrode is an excellent electrocatalyst for the detection of 4-CP compared to PEDOT and rGO. This counterpart exhibited a good linear relationship in the range of 5–250 μM, with a detection limit of 12 nM in the DPV technique. This sensor was also employed for the determination of 4-CP in river water samples. The accuracy of the analytical electrochemical sensor for 4-CP was comparatively analyzed using the obtained UV–visible spectral data, indicating a detection limit of 21 nM. Hence, the electrochemical method was successfully employed to obtain a lower detection limit for 4-CP than that for electronic absorption spectral observations. All the observed results were consistent with our expectations and showed that this novel PEDOT-rGO/GCE has good repeatability and stability and without any impactable interference behavior.

Biomimetic anti-fouling interface engineering based on thorn-vine-like structure for electrochemical sensing

Electrochemical sensing interfaces face an enormous obstacle posed by the non-specific adsorption in complex matrixes. This will decrease the current and sensitivity of electrochemical sensors. Since most biomarkers, especially those associated with diseases such as cancer, exist in trace amounts, sensitive detection is essential for them. However, it is a considerable challenge to develop anti-fouling interface strategies that can achieve highly sensitive electrochemical sensing in complex matrixes. Herein, a novel biomimetic anti-fouling interface engineering strategy was constructed based on thorn-vine-like structure for electrochemical biosensing. Bovine serum albumin (BSA) and sulfobetaine methacrylate (SBMA) underwent a thiol-ene click reaction, followed by electrostatic interaction with multi-walled carbon nanotubes (MWCNT), resulting in the thorn-vine-like structure BSA-PSBMA-MWCNT (BPSMC), with a highly three-dimensional network structure. The BPSMC not only significantly reduced non-specific adsorption, but also effectively enhanced the ability of the sensing interface to transfer electrons to the electrode surface. The impedance change ratio of the BPSMC-modified glassy carbon electrodes (GCE) was only 5.30% compared to the bare GCE when treated in undiluted serum samples for 2 h. As a proof of concept, the tumor biomarker ferritin (FER) was applied as a model analyte. By functionalizing the interface with specific antibodies, it enables quantification of FER in undiluted serum samples with ultra-high sensitivity. This biomimetic anti-fouling interface engineering strategy possesses excellent anti-fouling property, sensitivity, and universality and offers great potential for anti-fouling interfaces in complex matrices for medical and non-medical applications.

A new generation of fully-printed electrochemical sensors based on biochar/ethylcellulose-modified carbon electrodes: Fabrication, characterization and practical applications

Biochar is a material prepared by biomass pyrolysis, representing a more sustainable and efficient alternative to commonly used conventional carbon materials in electroanalysis. The aim of this paper is to point out that it can also show significant potential in the mass screen-printing production of miniaturized, low-cost, disposable and sensitive electrochemical sensors. Herein, a new generation of fully screen-printed electrochemical sensors is introduced, based on biochar/ethylcellulose-modified carbon working electrodes. The optimization in the sensor fabrication, involving the variability in the concentration of a binder and rheology modifier (ethylcellulose) and its impact on biochar inks from the viewpoint of viscoelasticity, printability and thermal stability, was performed to obtain the carbon-based electrochemical sensors with favourable robustness. The viability of these electrochemical sensors was demonstrated by the development and full validation of a new and sensitive differential pulse voltammetric method for the fast and reliable determination of paracetamol in pharmaceutical formulations. Within the method development, all necessary aspects, such as a study of the effect of ethylcellulose concentration, pH study of supporting electrolyte, selection of pulse parameters and analytical performance, were investigated. The obtained results allow us to predict the production and subsequent use of new, printable, cheap and environmentally friendly sensor platforms, which will exhibit convenient analytical performance with the possibility of commercialization.

Label-free electrochemical sensing platform for sensitive detection of ampicillin by combining nucleic acid isothermal enzyme-free amplification circuits with CRISPR/Cas12a

The residue of ampicillin (AMP) in food and ecological environment poses a potential harm to human health. Therefore, a reliable system for detecting AMP is in great demand. Herein, a label-free and sensitive electrochemical sensor utilizing NH2–Co-MOF as an electrocatalytic active material for methylene blue (MB) was developed for rapid and facile AMP detection by combining hybridization chain reaction (HCR), catalytic hairpin assembly (CHA) with CRISPR/Cas12a. The surface of glassy carbon electrode modified with NH2–Co-MOF was able to undergo HCR independent of the AMP, forming long dsDNA complexes to load MB, resulting in strong original electrochemical signal. The presence of AMP could trigger upstream CHA circuit to activate the CRISPR/Cas12a system, thereby achieving rapid non-specific cleavage of the trigger ssDNA of HCR on the electrode surface, hindering the occurrence of HCR and reducing the load of MB. Significant signal change triggered by the target was ultimately obtained, thus achieving sensitive detection of the AMP with a detection limit as low as 1.60 pM (S/N = 3). The proposed sensor exhibited good stability, selectivity, and stability, and achieved reliable detection of AMP in milk and livestock wastewater samples, demonstrating its promising application prospects in food safety and environmental monitoring.

Spherical Silver Nanoparticles Located on Reduced Graphene Oxide Nanocomposites as Sensitive Electrochemical Sensors for Detection of L-Cysteine.

A new, simple, and effective one-step reduction method was applied to prepare a nanocomposite with spherical polycrystalline silver nanoparticles attached to the surface of reduced graphene oxide (Ag@rGO) at room temperature. Equipment such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR) was used to characterize the morphology and composition of the Ag@rGO nanocomposite. A novel electrochemical sensor for detecting L-cysteine was proposed based on fixing Ag@rGO onto a glassy carbon electrode. The electrocatalytic behavior of the sensor was studied via cyclic voltammetry and amperometry. The results indicate that due to the synergistic effect of graphene with a large surface area, abundant active sites, and silver nanoparticles with good conductivity and high catalytic activity, Ag@rGO nanocomposites exhibit significant electrocatalytic activity toward L-cysteine. Under optimal conditions, the constructed Ag@rGO electrochemical sensor has a wide detection range of 0.1-470 μM for L-cysteine, low detection limit of 0.057 μM, and high sensitivity of 215.36 nA M-1 cm-2. In addition, the modified electrode exhibits good anti-interference, reproducibility, and stability.

Highly Sensitive Electrochemical Sensor Based on a Solvent-Processing Cobalt Phthalocyanine for Detection of Ascorbic Acid

Highly Sensitive Electrochemical Sensor Based on a Solvent-Processing Cobalt Phthalocyanine for Detection of Ascorbic Acid

Facile surface modification of the poly(l-cysteine) on 2D-printed reduced graphene oxide electrode to fabricate a highly sensitive electrochemical sensor for determining the antipsychotic drug olanzapine

Amino acid-based polymers are alternative modifiers for electrode surface modification that can be simply and rapidly synthesized through electrochemical methods. Hence, we aim to develop a novel and easy-to-construct electrochemical sensor based on a two-dimensional-printed reduced graphene oxide electrode modified with poly(l-cysteine) for the determination of the antipsychotic drug olanzapine. The poly(l-cysteine) was employed as the only modifier for electrode surface modification, which was conducted via a single-step electropolymerization procedure. The surface composition and morphology of the developed sensor were examined by using a field emission scanning electron microscope, energy-dispersive X-ray spectroscopy, fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The electrochemical characterization of the sensor was also performed by utilizing cyclic voltammetric and electrochemical impedance spectroscopic techniques. All electrochemical parameters and analytical performances of interest were thoroughly investigated. Under optimal conditions, the developed approach showed broad linear dynamic ranges of 10–1000 and 1500–5000 nM and a low detection limit of 0.91 nM in the detection of trace amounts of olanzapine. When the proposed approach was used to analyze olanzapine in human serum samples to verify its feasibility, it exhibited high accuracy and good precision. In contrast to conventional electrodes, our newly developed electrochemical electrode could be an appropriate device for monitoring the effectiveness and safety of the antipsychotic drug olanzapine.

Development of a new highly sensitive electrochemical sensor to piroxicam anti-inflammatory determination using a disposable screen-printed electrode

Development of a new highly sensitive electrochemical sensor to piroxicam anti-inflammatory determination using a disposable screen-printed electrode

Development of a Cr2AlC MAX phase/g-C3N4 composite-based electrochemical sensor for accurate cabotegravir determination in pharmaceutical and biological samples.

Ahighly sensitive electrochemical sensor is reportedthat employs a modified electrode for the precise measurement of cabotegravir, a potent anti-HIV drug. Cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS) were utilized for this purpose. Electrode modification involved the immobilization of Cr2AlC MAX phase/g-C3N4 onto a glassy carbon electrode (GCE) to enhance its electrocatalytic activity and selectivity for cabotegravir detection. Under the optimal experimental conditions, the working potential (vs. Ag/AgCl) was to 0.93V. The developed sensor exhibited a good linear relationship in the range 0.05µM to 9.34µM with a low limit of detection of 4.33nM, signifying its exceptional sensitivity. Additionally, it demonstrated successful cabotegravir detection in pharmaceutical formulations and biological samples, achieving an RSD below 3.0%. The recoveries fell within the range 97.7 to 102%, confirming the sensor's potential for real-sample applications. This innovative electrochemical sensor represents a significant advancement, providing a simple, reliable, and sensitive tool for the accurate measurement of cabotegravir. Its potential applications include optimizing drug dosages, monitoring treatment responses, and supporting the development of cabotegravir-based pharmaceutical products, thereby contributing to advancements in HIV therapy and prevention strategies.