Glassy Carbon Research Articles

Designing a molecularly imprinted polymer-based electrochemical sensor for the sensitive and selective detection of the antimalarial chloroquine phosphate.

For the first time anelectrochemical sensor based on nanomaterial-supported molecularly imprinted polymers (MIPs) is applied to the sensitive and specific determination of chloroquine phosphate(CHL). The sensor was produced using an electropolymerization (EP) approach, and it was formed on a glassy carbon electrode (GCE) using CHL as a template and 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) and aniline (ANI) as functional monomers. Incorporating Prussian blue polyethyleneglycol-amine nanoparticles (PB@PEG-NH2) in the MIP-based electrochemical sensor increased the active surface area and porosity. The developed CHL/AMPS-PANI/PB@PEG-NH2/MIP-GCE sensor was characterized morphologically and electrochemically using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and scanning electron microscopy (SEM). The indirect measurement of CHL was accomplished in 5.0mmol L-1 [Fe(CN)6]-3/-4 solutionusing differential pulse voltammetry, displaying linear response between 1.75 × 10-12 and 2.50 × 10-13M, and limits of detection (LOD) and quantitation (LOQ) of 6.68 × 10-14M and 2.23 × 10-13M, respectively, in standard solutions. CHL recoveries in spiked serum and tablet form ranged from 99.13 to 101.51%, while the relative standard deviations (RSD%) were below 2.41% in both types of samples. In addition, the sensor's excellent selectivity was successfully demonstrated in the presence of components with a chemical structure similar to CHL.

Simultaneous Electrochemical Determination of Sildenafil Citrate and Tadalafil Using a Multi Walled Carbon Nanotubes Modified Glassy Carbon Electrode by Adsorptive Stripping Linear Sweep Voltammetry

AbstractAn adsorptive stripping linear sweep voltammetric method was developed for the simultaneous determination of sildenafil citrate and tadalafil. The voltammetric working electrode was a glassy carbon electrode modified with carboxylic multi‐walled carbon nanotubes. The sensitivity of the developed voltammetric method was significantly increased by this modification. Both analytes spontaneously adsorbed on the modified electrode surface due to their adsorption affinities. The irreversible oxidation signals of both analytes were used as the analytical signals. The electrochemical behaviour of sildenafil citrate and tadalafil was assessed using cyclic voltammetry. The developed voltammetric method was linear in the range of 0.01–0.50 μM with a correlation coefficient of 0.9997 and 0.9985 for sildenafil citrate and tadalafil, respectively. The LOQs of the method for both analytes were 0.010 μM. The intra‐ and inter‐day reproducibility of the method was less than 10% RSD in all cases. The extraction recoveries for both analytes ranged between 83 and 94%. The applicability of the developed voltammetric method were investigated by determining the analyte in two different spiked samples (an energy drink and a traditional herbal product). Furthermore, the described method would represent the first electrochemical approach for the simultaneous detection of sildenafil citrate and tadalafil, providing an available alternative to current chromatographic techniques.

Sensitive detection of gallic acid in food by electrochemical sensor fabricated by integrating nanochannel film with nanocarbon nanocomposite

Sensitive detection of gallic acid (GA) in foods is of great significance for assessing the antioxidant properties of products and ensuring consumer health. In this work, a simple electrochemical sensor was conveniently fabricated by integrating vertically-ordered mesoporous silica film (VMSF) with electrochemically reduced graphene oxide (ErGO) and nitrogen graphene quantum dots (NGQDs) nanocomposite, enabling sensitive detection of GA in food sample. A water-soluble mixture of graphene oxide (GO) and NGQDs was drop-cast onto the common carbon electrode, glassy carbon electrode (GCE), followed by rapid growth of VMSF using an electrochemically assisted self-assembly method (EASA). The negative voltage applied during VMSF growth facilitated the in situ reduction of GO to ErGO. The synergistic effects of ErGO, NGQDs, and the nanochannels of VMSF led to nearly a tenfold enhancement of the GA signal compared to that obtained on electrodes modified with either ErGO or NGQDs alone. Sensitive detection of GA was realized with a linear concentration range from 0.1 to 10 μM, and from 10 to 100 μM. The limit of detection (LOD), determined based on a signal-to-noise ratio of three (S/N = 3), was found to be 81 nM. Combined with the size-exclusion property of VMSF, the fabricated sensor demonstrated high selectivity, making it suitable for the sensitive electrochemical detection of gallic acid in food samples.

CNT aerogel film based novel approach for development of ultra-sensitive electrochemical sensor platforms with glassy carbon, screen-printed, and interdigitated electrodes

CNT aerogel film based novel approach for development of ultra-sensitive electrochemical sensor platforms with glassy carbon, screen-printed, and interdigitated electrodes

Determination of Mn2+ in seawater used an in situ shipborne detection device coupled with the glassy carbon electrode

Determination of Mn2+ in seawater used an in situ shipborne detection device coupled with the glassy carbon electrode

An Enzyme-Free Impedimetric Sensor Based on Flower-like NiO/Carbon Microspheres for L-Glutamic Acid Assay

This research introduces a non-enzymatic electrochemical sensor utilizing flower-like nickel oxide/carbon (fl-NiO/C) microspheres for the precise detection of L-glutamic acid (LGA), a crucial neurotransmitter in the field of healthcare and a frequently utilized food additive and flavor enhancer. The fl-NiO/C were synthesized with controllable microstructures using metal–organic frameworks (MOFs) as precursors followed by a simple calcination process. The uniformly synthesized fl-NiO/C microspheres were further characterized using Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and field emission scanning electron microscopy (FE-SEM). The fl-NiO/C was utilized as a modifier on the surface of a glassy carbon electrode, and an impedimetric sensor based on electrochemical impedance spectroscopy (EIS) was developed for the detection of LGA. The proposed sensor demonstrated excellent catalytic activity and selectivity towards LGA across a broad concentration range of 10–800 μM with a sensitivity of 486.9 µA.mM−1.cm−2 and a detection limit of 1.28 µM (S/N = 3). The sensor was also employed to identify LGA in blood plasma samples, yielding results that align with those obtained through HPLC. This achievement highlights the potential of fl-NiO/C microspheres in advancing cutting-edge biosensing applications.

Efficient biosorption of Zn(II), Cd(II), and Pb(II) by Aspergillus brasiliensis in industrial wastewater coupled with electrochemical monitoring via sensor enhanced with modified silver nanoparticles.

This work investigates the use of Aspergillus brasiliensis, this particular species of Aspergillus, as a biosorbent for the first time. It is employed to biosorption Zn(II), Cd(II), and Pb(II) and combines the biosorption experiments with electrochemical measurements for in situ analysis. For the experiments, a batch system was employed with the dead biomass. In order to determine the biosorption capacity, the impact of several operational parameters was examined, including pH, temperature, agitation speed, contact time, and initial metal concentration, and the optimum values were 5, 30°C, 150rpm, 2h, and 150ppm, respectively. Using 0.2g biomass in 100mL solution, the maximal uptake of Zn(II), Cd(II), and Pb(II) at ideal conditions was determined to be 33.67, 24.51, and 36.76, respectively. The Langmuir and Freundlich isotherm model was studied for the biosorption process. An electrochemical sensor using nanomaterials is designed and constructed to monitor the concentration of these metals. The silver nanoparticles functionalized with thiosemicarbazide and 6-mercaptohexanoic acid (mercaptohexanoylhydrazinecarbothioamide-coated silver nanoparticles, MHHC-AgNPs) linked to the carboxylated multi-walled carbon nanotubes (MWCNTs) were utilized for glassy carbon electrode modification (MHHC-AgNPs/MWCNTs/GCE). The concentration range of Zn(II) is 0.7-173µg/L, Cd(II) is 1.18-293µg/L, and Pb(II) is 2.17-540µg/L. The detection limits for Zn(II), Cd(II), and Pb(II) are 0.036µg/L, 0.15µg/L, and 0.16µg/L, respectively. Under optimized conditions, these results were obtained using the differential pulse anodic stripping voltammetry method (DPASV). The successful detection of Zn(II), Cd(II), and Pb(II) was achieved by effectively preventing interference from other common ions. It was effectively employed for measuring ions in industrial wastewater, and the results obtained aligned with those acquired from an atomic absorption spectrometer (AAS). Thus, Aspergillus brasiliensis species, along with this electrochemical sensor, can be used to remediate and monitor environmental pollution, Zn(II), Cd(II), and Pb(II), successfully.

Hexagonal Morphology Nickel Sulfide Anchored on Graphene Oxide–Modified Glassy Carbon Electrode for the Sensitive Detection of Paracetamol in Biological Samples

Hexagonal Morphology Nickel Sulfide Anchored on Graphene Oxide–Modified Glassy Carbon Electrode for the Sensitive Detection of Paracetamol in Biological Samples

Tripartite Detection and Sensing of Toxic Heavy Metals Using a Copper-Based Porphyrin Metal-Organic Framework.

The detection of heavy metals in water sources is a critical concern for environmental preservation and public health. However, current electrochemical heavy metal sensors suffer from high sensing limits, cross-sensitivity, and poor selectivity. In this work, we present the possibility of an electrochemical sensor based on a copper (Cu) metal-organic framework for the detection of lead, cadmium, and mercury by replacing Cu metal nodes. The working electrode consists of a ∼5 μm thin layer of copper- tetracarboxyphenylporphyrin (Cu-TCPP) sheets that are adsorbed on a glassy carbon electrode (GCE). Upon interaction with Pb2+, Cd2+, and Hg2+, these ions are adsorbed on and incorporated into the metal nodes of the MOF. The adsorbed metallic species can be oxidized to the ionic form (Pb → Pb2+) electrochemically, which results in an oxidation response and enables the quantitative detection of these metals. The oxidation peak currents follow a (mostly) bimodal linear regression with a sensing range of up to 30 μM dependent on the deposition time and an ultralow limit of detection (LoD) of up to 5 nM. The system displays robust and selective sensing in saturated solutions of counterions and interfering metal ions (low error margins of <10%). This work represents the first report of a Cu-TCPP-modified GCE anode as an effective electrode for the sensitive detection of multiple heavy metals and an in-depth study into the Cu replacement kinetics of the Cu-MOF.

Electroanalysis of Statin Drugs: A Review on the Electrochemical Sensor Architectures Ranging from Classical to Modern Systems.

An 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.

MXene/NiCu-MOF//AC Nanocomposite Electrode: A Dual-Functional Platform for Energy Storage and Real-Time Monitoring of Monosodium Glutamate Based Sensors

Abstract Monosodium glutamate (MSG), also known as sodium glutamate, is a widely used food additive in commercial foods, and controlling its level is essential for ensuring food safety and quality. For the detection of MSG, the hydrothermal approach is used to synthesize both MXene and NiCu-MOF. Scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were manipulated to examine the composite morphology, structure, and composition. The MXene/NiCu-MOF electrode displayed an exceptional specific capacity of 277 Cg-1 at a scanning speed of 1.3 mVs-1. The MXene/NiCu-MOF//AC electrode exhibited an exceptional (Cs) of 271.64 Cg-1 at 2 Ag-1 when employed in a supercapattery. The device demonstrated excellent performance, attaining a (Pd) of 1946.21W kg-1 and (Ed) of 37.17 Wh kg-1. Furthermore, MXene/NiCu-MOF//AC demonstrated exceptional capacity retention of 81% after 5,000 cycles in the reliability test. The MSG was utilized as a glassy carbon electrode which was enhanced with gold nanoparticles. The current detection technique implemented NiCu- MOF/MXene as a conductive matrix, with the use of an anti-glutamate antibody. The correlation remained stable from 0.05 to 200 µM detection range. The multipurpose MXene/NiCu-MOF nanocomposite electrode material opens up possibilities for developing novel hybrid devices in energy harvesting.

Enhanced 3D-printed Matrix for Electrocatalytic Detection: A Practical and Simple Electrochemical Platform

AbstractIn this work, we proposed a novel 3D-printed manufactured electrode system. A project was developed and optimized, compatible with commercially available potetiostats. Additive manufacturing included the modification of the pseudo-reference electrode by electrodeposition of silver and its subsequent oxidation to the Ag/AgCl form. Then the system was tested using electrochemical techniques to check the application as a universal electroactive platform. As an example, we checked the detection of paracetamol as a common substance from non-steroidal anti-inflammatory drugs (NSAIDs). Finally, the system was compared to available commercial carbon electrodes, considering the screen-printed electrode (SPE no.1 and SPE no.2) and the glassy carbon electrode (GCE), showing higher sensitivity and linearity range compared to commercial screen-printed systems. The novelty of the proposed platform unveils a new way of common, simple, budget, and fast obtaining a universal electroactive platform for electrochemical research, keeping high-performance parameters.

Impedimetric immunosensor versus qPCR for Huanglongbing detection

Citriculture is facing challenges due to the spread of various diseases, among which the most threatening, with worldwide occurrence, is Huanglongbing (HLB), caused by the bacteria Candidatus Liberibacter spp., vectored by psyllids. In orchards, HLB-infected plants are identified by visual observation of symptoms. For laboratory diagnosis, the gold standard is the polymerase chain reaction (PCR), requiring expertise and specific equipment, and with high financial cost. In this work, a selective impedimetric immunosensor was developed for the detection and determination of Ca. L. asiaticus (CLas) in citrus samples. An anti-HLB antibody against the outer membrane protein (OMP) sequence of CLas was obtained and immobilized on previously synthesized and characterized magnetic nanoparticles. The immobilized antibody was presented to various citrus leaf sample extracts. After the affinity reaction with the antigen, a washing step was performed to minimize matrix effects. The affinity reaction was monitored by electrochemical impedance spectroscopy, using a glassy carbon working electrode containing a neodymium magnet. The developed device was able to distinguish HLB-positive samples from HLB-negative samples and those with other infections. The results obtained with the proposed methodology were in good agreement with quantitative PCR (qPCR).

Construction of electrochemical immunosensors based on Au@MXene and Au@CuS nanocomposites for sensitive detection of carcinoembryonic antigen

Cancer is currently one of the major causes of human mortality and has received widespread attention. In this paper, Au@CuS composite nanomaterial as a sandwich immunosensor tag for carcinoembryonic antigen (CEA) detection strategy was studied. Herein, Au@CuS composite nanomaterials were obtained by Au nanoparticles modified with CuS, which were combined with secondary antibody (Ab2) to construct an immunosensor that interacted with H2O2 to produce a current response. The anti-CEA primary antibody (Ab1) was fixed on the glassy carbon electrode (GCE) modified by Au@MXene. The completed electrochemical immunosensor was constructed with rapid detection and high sensitivity for CEA. Under optimal conditions, the linearity ranged from 0.01 pg/mL to 0.5 ng/mL, and the detection limit was 3.8 fg/mL. This tactic possesses good reproducibility, constancy and selectivity. At the same time, this strategy has latent practical value for the test of other tumor markers.

Highly sensitive electrochemical detection of ciprofloxacin using MXene (Ti3C2Tx)/poly (rutin) composite as an electrode material

Ciprofloxacin is a widely used antibiotic for treating numerous bacterial infections and it is also considered by the world health organization (WHO) to be extremely vital for human medicine. Therefore, accurate, simple, and cost-effective detection of ciprofloxacin, a commonly used antibiotic, is critical for treating various bacterial infectious diseases. In this work, glassy carbon electrode/poly (rutin)/Ti3C2Tx, is developed for the detection of ciprofloxacin antibiotic. The electrochemical sensor was modified with rutin hydrate monomer and Ti3C2Tx via electro-polymerization of rutin hydrate and drop-casting of Ti3C2Tx. The modified electrode surface was characterized using scanning electron microscopy, high-resolution transmission electron microscopy, attenuated total reflectance- Fourier transform infrared spectroscopy, and electrochemical impedance spectroscopy. The oxidation of ciprofloxacin was performed in 0.01molL−1 of phosphate buffer at a pH level of 5.0. This medium established a linear range of 1.0 × 10−9-1.0 × 10−4 molL−1, limit of detection at 1.0 × 10−9 molL−1 and sensitivity of 0.49 μA/μMcm2. Finally, the modified electrode displayed high selectivity when tested in inorganic-organic mixtures as well as in real sample medium such as blood serum. To the best of our knowledge the current work is the first to report the use of MXene/rutin composite for electrochemical sensing mechanism. The proposed electrochemical sensor has high potential for the formation of therapeutic drug doses application via monitoring of CIP patient intake (clinical settings of CIP).

Y/Co-MWCNT nanocomposite conjugated Nafion modified glassy carbon electrode for sensitive detection of thiourea chemical by electrochemical approach

Y/Co-MWCNT nanocomposite conjugated Nafion modified glassy carbon electrode for sensitive detection of thiourea chemical by electrochemical approach

Development of novel hybrid hydroxyapatite-based sensors for the ultrasensitive detection of L-tryptophan and L-tyrosine

A novel sensor using gold (Au) doped citrate-hydroxyapatite nanoparticles at different molar ratios wCitHAP-Au (w = 0.2, 0.4, 0.8) was developed. Citrate groups on the HAP nanoparticles surface makes it possible to carry out directly and homogeneously the “one-pot” deposition of the 0.5 % AuNPs from an aqueous solution. wCitHAP-0.5Au modified glassy carbon electrodes (GCE) are used in fundamental studies of the electron transfer, and in the construction of sensor devices for the determination of L-Tryptophane (TTP) and L-Tyrosine (TYR). Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV) reveal the excellent electrocatalytic activity for oxidation and determination of TTP and TYR into phosphate buffer solution at pH 7 of the 0.2CitHAP-0.5Au/GCE electrode. Linear response ranges under optimal conditions were found to be 3.33 nM to 66.6 μM for TTP and 6 nM to 66.6 μM with detection limit of 3.33 nM and 6 nM, respectively. The fabricated sensor shows suitable sensitivity, stability, and can successfully applied for real samples determination.Additionally, Hirshfeld Surface (HS) analysis was conducted to gain deeper insights into the molecular properties, intermolecular interactions, and surface characteristics of the compounds studied. The HS analysis confirmed the presence of intermolecular interactions that stabilize the gold nanoparticles within the hydroxyapatite-citrate matrix, ensuring their uniform distribution and preventing aggregation.

Analysis of Galvanostatic Data from Electrochemical Capacitors

The ability to deconvolute charge storage mechanisms in electrochemical capacitor materials and systems is essential for understanding and improving behaviour. From an electrochemical perspective, this deconvolution can be achieved through an understanding of the expected response of a particular contribution. Voltametric measurements can be deconvoluted through the current response relative to the applied sweep rate. Herein we describe an analogous approach for galvanostatic data in which the charge or discharge time is related to the applied current (I). Specifically, capacitive charge storage is shown proportional to I−1, while diffusional processes are proportional to I2. Coupling this with a constant contribution from ohmic and residual charge storage processes allows for an effective approach to deconvolution for galvanostatic data. This is demonstrated with data from a glassy carbon electrode in non-aqueous electrolyte (an expected electrical double layer system) and from a manganese dioxide electrode in aqueous electrolyte (an expected pseudo-capacitive system).

Fluid-Specific Detection of Environmental Pollutant Moxifloxacin Hydrochloride Utilizing a Rare-Earth Niobate Decorated Functionalized Carbon Nanofiber Sensor Platform

The development of precise and efficient detection methods is essential for the real-time monitoring of antibiotics, especially in environmental and biological matrices. This study aims to address this challenge by introducing a novel electrochemical sensor for the targeted detection of moxifloxacin hydrochloride (MFN), a fourth-generation fluoroquinolone. The sensor is based on a holmium niobate (HNO) and functionalized carbon nanofiber (f-CNF) nanocomposite, synthesized via a hydrothermal approach and subsequently characterized for its structural and electrochemical properties. When deposited onto a glassy carbon electrode (GCE), the HNO/f-CNF nanocomposite demonstrated exceptional electrochemical performance, as assessed using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The sensor exhibited remarkable sensitivity, with a detection limit of 0.034 μM, a quantification limit of 0.11 μM, and a sensitivity of 0.69 μA μM-1 cm-2. It also achieved a broad linear detection range from 0.001 μM to 1166.11 μM, making it highly effective for MFN detection across various complex matrices, including environmental waters, biological fluids, and artificial saliva, with recovery rates between 98.15% and 101.75%. The novelty of this work lies in the unique combination of HNO's catalytic properties and f-CNF's enhanced electron transport, establishing a highly selective and sensitive platform for MFN detection. This sensor not only advances the field of electrochemical sensing but also offers a promising tool for real-time environmental and pharmaceutical monitoring.

Facile Microwave-Assisted Growth of 3D ZnVO Nanomarbles on Graphene Oxide Nanosheets for Simultaneous Detection of Ascorbic Acid, Dopamine, and Uric Acid

Simultaneous detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA) is challenging due to close oxidation potential. These biomolecules lie in the human body and have significant roles in many psychological reactions. A slight change in the concentration of these molecules can cause serious health issues; in this context, accurate and timely detection holds significant value in clinical diagnostics. This work demonstrates the synthesis of 3D zinc nanomarbles on 2D graphene oxide sheets using a rapid and environmentally friendly microwave-assisted technique. The porous morphology with thin nanomarbles where (2 2 0) reactive sites were exposed to the environment with enhanced surface area measured 38.29 m2 g-1. The composite ZnVO/rGO has been employed on glassy carbon electrodes, resulting in superior electrocatalytic properties that enable the simultaneous detection of these analytes with wide potential gaps. Notably, the ZnVO/rGO/GCE exhibits simultaneous detection with a working range of AA (100 µM-1000 µM), DA (10 µM-100 µM), and UA (10 µM-100 µM). The detection limits were estimated to be 4.3µM, 0.7µM, and 0.32µM, respectively. The ZnVO/rGO/GCE sensor demonstrates remarkable stability, selectivity, reproducibility, and satisfactory recovery during real sample analysis. The high surface area, porous nature, and thin size of 3D nanomarbles enhance charge transportation, making it promising for electrochemical performance. This study lays the foundation for future advancements in human health monitoring by introducing a novel approach.