Electrochemical Determination Research Articles

Carbonaceous materials–20: electrochemical determination of viloxazine on a novel carbonaceous template

Carbonaceous materials–20: electrochemical determination of viloxazine on a novel carbonaceous template

Microwave-Assisted Bio-derived Bismuth Oxybromide (BiOBr) Decorated Polyaniline Nanocomposite for Highly Sensitive Electrochemical Determination of Endocrine Disruptor Bisphenol-A

In the presence of polyaniline (PANI), the novel nanocomposites of PANI-BiOBr bismuth oxybromide (BiOBr) were synthesized using a microwave-assisted green synthesis method and used to detect bisphenol A (BPA). By using fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and electrochemical methods, the hybrid PANI-BiOBr nanocomposite was confirmed. The higher conductivity, improve active surface-to-volume ratio, and enhanced electrochemical behaviour of the PANI-BiOBr nanoplatform can be attributed to the synergistic actions of PANI and BiOBr. With a high sensitivity of 11.7 μA (log nM)-1 cm2 and a low limit of detection of 0.19 × 10−9 μM, the constructed PANI-BiOBr sensor exhibits a broad linear range from 0.19 × 10−9 μM to 3.04 × 10−3 μM. In addition, this sensor produced adequate findings with outstanding selectivity, stability, repeatability, and reproducibility. Furthermore, the developed electrochemical PANI-BiOBr nanoplatform is essential in analysing real-world materials to detect BPA. The results obtained from these real sample analyses not only confirmed the effectiveness of the PANI-BiOBr nanocomposite sensor for BPA detection but also underscored its capability to detect other compounds with estrogenic properties, beyond just BPA.

Electrochemical determination of caffeine in coffee and non-alcoholic drinks using g-C3N4-ZnO modified glassy carbon electrode

Caffeine is a very important ingredient for preserving the nutritional quality of foods. But, when ingested in excess, it is responsible for numerous health problems, hence the analysis of caffeine in drinks and food products is a pivotal. This study employed g-C3N4/ZnO nanocomposite (NC) to analyze caffeine in coffee and soft drinks. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) were employed for structural characterization. Caffeine oxidation was successfully accomplished by modifying glassy carbon electrodes (GCEs) with g-C3N4/ZnO NC. The sensitivity of caffeine detection using g-C3N4/ZnO/GCE was noticeably improved because of its better electrocatalytic activity. The sensor showed good analytical performances like selectivity, inter-electrode reproducibility, and stability. It also responded a wide range to caffeine concentrations between 1 and 1000 µM. The estimated limit of detection (LOD) and quantification (LOQ) were found to be 0.063 µM and 0.211 µM, respectively. Caffeine content of real samples has also been effectively determined with recovery values of 91.41–103.84 %.

Screen-printed electrode modified with a composite based on Amburana cearensis gum, multi-walled carbon nanotubes, and gold nanoparticles for electrochemical determination of total isoflavones in soybean cultivars

Screen-printed electrode modified with a composite based on Amburana cearensis gum, multi-walled carbon nanotubes, and gold nanoparticles for electrochemical determination of total isoflavones in soybean cultivars

Fabrication of Strontium Molybdate with Functionalized Carbon Nanotubes for Electrochemical Determination of Antipyretic Drug-Acetaminophen.

In recent years, there has been a significant interest in the advancement of electrochemical sensing platforms to detect antipyretic drugs with high sensitivity and selectivity. The electrochemical determination of acetaminophen (PCT) was studied with strontium molybdate with a functionalized carbon nanotube (SrMoO4@f-CNF) nanocomposite. The SrMoO4@f-CNF nanocomposite was produced by a facial hydrothermal followed by sonochemical treatment, resulting in a significant enhancement in the PCT determination. The sonochemical process was applied to incorporate SrMoO4 nanoparticles over f-CNF, enabling a network-like structure. Moreover, the produced SrMoO4@f-CNF composite structural, morphological, and spectroscopic properties were confirmed with XRD, TEM, and XPS characterizations. The synergistic effect between SrMoO4 and f-CNF contributes to the lowering of the charge transfer resistance (Rct=85 Ω·cm2), a redox potential of Epc=0.15 V and Epa=0.30 V (vs. Ag/AgCl), and a significant limit of detection (1.2 nM) with a wide response range of 0.01-28.48 µM towards the PCT determination. The proposed SrMoO4@f-CNF sensor was studied with differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques and demonstrated remarkable electrochemical properties with a good recovery range in real-sample analysis.

Electrochemical Performance of Polyaniline‐Polyvanadate‐Copper Nanomaterials for the Detection of Benzoic Acid

AbstractThe introduction of nanomaterials as modified electrode materials into the field of electrochemical sensing is expected to improve the reliability, sensitivity, selectivity and repeatability of electrochemical sensors in detecting pollutants in the water environment. In this study, copper vanadate nanomaterials (Cu3V2O7(OH)2·2H2O, referred to as CVO) and Cu3V2O7(OH)2·2H2O/polyyaniline (PANI) composite nanomaterials (referred to as CVO/PANI) are successfully prepared and characterized by Fourier transform infrared spectrum (FTIR), X‐ray traveling‐action (XRD), scanning electron microscopy (SEM) and high‐resolution transmission electron microscopy (HR‐TEM). The modified glassy carbon electrodes (GCE) with these two materials are used for the detection of benzoic acid (BA) and exhibit excellent electrochemical sensing performance. The results show that two pairs of semi‐reversible redox peaks exist in both CVO and CVO/PANI modified glassy carbon electrode (GCE) in BA solution. The linear range of CVO and CVO/PANI nanomaterials‐modified GCE is 0.01–2 mm and 0.001–2 mm, and the limits of detection are 2.16 and 0.41 µm, respectively. PANI plays important role in the electrochemical responses of BA at CVO/PANI modified GCE. PANI enhances the intensities of CV peaks and electrochemical determination ability for BA.

2D-network of boron-functionalized N-doped graphene quantum dots for electrochemical sensing of dopamine

A glassy carbon electrode (GCE) modified by boron-functionalized N-doped graphene quantum dots (B-GQDs) was employed for the electrochemical determination of dopamine (DA), a neurotransmitter. The B-GQDs were obtained by hydrothermal etching of GO with H2O2 and NH3 in the presence of H3BO3. By using various techniques, including transmission electron microscopy, atomic force microscopy, molecular absorption spectrometry, fluorescence, ICP-MS, and zeta potential analysis, it was demonstrated that B-GQDs are self-organized in 2D-network, being N-doped GQDs nanoparticles crosslinked by H3BO3. The GCE modification was carried out using the drop-casting method with B-GQDs in Nafion®, previously dispersed through ultrasonication. For the first time, the synthesized nanomaterial was tested in the electroanalysis of neurotransmitters. The B-GQDs/Nafion®/GCE modification led to a significant increase in peak currents in the presence of DA. The electrochemical and interfacial characteristics of the sensors were evaluated by cyclic voltammetry (CV). Under optimized square wave voltammetry and supporting electrolyte conditions, a linear dependence between the anodic peak current and DA concentration was observed in the range of 0.7 to 188 μmol L−1 (R2 = 0.9991). The limit of detection (LOD) was estimated at 0.05 μmol L−1. Selectivity was confirmed in the presence of potential interferents found in urine, with interference response below 12 %. The sensor exhibited excellent intra-day and inter-day repeatability, with a relative standard deviation of 4.12 % and 4.66 %, respectively. Electrochemical determination of DA was conducted in artificial urine samples (Surine®), with recovery values of 90–101 %. The new analytical platform B-GQDs/Nafion®/GCE demonstrated promising characteristics for application in biological and/or pharmaceutical analysis.

Electrochemical Determination of Catechol Using a Disposable Printed Electrode with Conductive Ink Based on Graphite and Carbon Black

Catechol (CT) is a phenolic compound widely used in various industrial sectors, but it is toxic; thus, there is a need for methods that aim to identify and quantify the existence of residues of this material in the environment. In this study a disposable printed electrochemical sensor was developed as an effective alternative for determining CT in water samples. The electrode, called SPEC, was manufactured using the screen-printing method using polyethylene terephthalate (PET) as a support, in which a conductive ink based on carbonaceous materials was used to print the working and auxiliary electrodes and a silver/silver chloride of ink on the reference electrode. The optimal ratio for the conductive ink was 6.25% carbon black, 35.42% graphite, and 58.33% nail polish. The ink obtained was characterized by scanning electron microscopy (SEM). The assessment of the effect of pH on the redox process showed Nernstian behavior (0.057 V pH−1), indicating that the process involves the same number of protons and electrons. Under optimized conditions, with 0.2 mol L−1 acetate buffer at pH 5.0, and by square wave voltammetry, the sensor presented sensitivity values of 0.31 μA L μmol−1, a detection limit of 5.96 μmol L−1, and a quantification limit of 19.87 μmol L−1. The sensor was applied to determine CT in tap water samples, and the results showed recoveries between 97.95 and 100.17%.

Flexible electrochemical sensor based on a ZnO-doped SnO2 heterojunction for simultaneous electrochemical determination of p-aminophenol and acetaminophen

In this work, a novel flexible electrochemical sensor was successfully developed for the simultaneous determination of p-aminophenol and acetaminophen. The sensor is composed of a methanesulfonic acid-treated poly(3,4-ethylenedioxythiophene)/poly (styrenesulfonic acid) film on a poly (ethylene terephthalate) substrate, which has been modified using a zinc oxide-doped tin oxide heterojunction applied through drop-coating (C-ZnO/SnO2-PEDOT/PET). The oxygen vacancies resulting from zinc oxide-doped tin oxide heterojunctions within highly conductive metal oxide nanomaterials enhance mass transfer and synergize seamlessly with methanesulfonic acid-treated electrically conductive dielectric PEDOT/PET films, leading to a substantial improvement in electrochemical activity. Under the optimal conditions, a wider linear range and lower detection limits were shown for para-aminophenol (2-511μM, LOD=0.437μM) and acetaminophen (2-591μM, LOD=0.562μM). In addition, the sensors demonstrated high accuracy in detecting para-aminophenol and acetaminophen in real samples, with recoveries of 99.36%-99.60% and 97.56%-99.80%, respectively. Furthermore, the flexible sensors maintained a superior electrochemical response when detecting para-aminophenol and acetaminophen at different bending angles, with relative standard deviations of 0.62% and 1.68%, respectively. These findings suggest potential applications for the development of wearable sensors in the future.

Indirect Electrochemical Determination of Carvedilol through its Interaction with Nitrous Acid

Indirect Electrochemical Determination of Carvedilol through its Interaction with Nitrous Acid

Electrosynthesis of a triazole derivative on the glassy carbon surface for the electrochemical determination of catechol

ABSTRACT In this experiment, an electrosynthesis of a triazole-thiol derivative (3-amino-1,2,4-triazole-5-thiol (3ATT)) was carried out on the glassy carbon electrode (GCE) to fabricate an electrochemical sensor to determine catechol (CC) by voltammetry. The characterisation of the modified electrode (3ATT-GCE) was examined by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Electrochemical oxidation of CC by the differential pulse voltammetry (DPV) with 3ATT-GCE exhibited a perfectly wide linear response in the CC concentration range of 0.088 to 10.5 µM and 10.5 to 629 µM with a detection limit (LOD) of 0.024 µM (3 s/m). Furthermore, it indicated excellent reproducibility and repeatability. The fabricated sensor with a large surface area and high electrical conductivity was successfully employed to determine CC in tap water without being affected by interfering substances.

Construction of MOF-74 derived CuFe/C alloy highly dispersed on ultrathin single layered reduced graphene for electrochemical determination of paracetamol

Paracetamol (PAT) is a widely used drug for fever reduction and pain relief, but its accumulation due to overuse can lead to detrimental effects on human health and environment. Here, a novel composite material CuFe/C@rGO with excellent electrochemical properties was successfully constructed by loading carbon-encapsulated CuFe alloy (CuFe/C) on ultrathin single layered reduced graphene oxide (rGO) surface for PAT detection. Firstly, the CuFe/C nanoparticles was derived from MOF-74 as bimetallic ‘preassembly platform’ to obtain high dispersiveness, huge accessible surface area, and uniform pore structure of the resulted material. And then the CuFe/C was uniformly dispersed on rGO to effectively avoid the aggregation of CuFe/C and increase the conductivity of composite material. In virtue of the synergistic effect of CuFe/C and rGO, the composite material modified glassy carbon electrode CuFe/C@rGO/GCE would be endowed with abundant electrocatalytic acitive sites and fast charge transfer speed between electrode surface and analyte. Expectedly, the CuFe/C@rGO/GCE shows outstanding sensing performance with wide linear ranges of 0.006–110 μM, low detection limit of 0.0015 μM (S/N=3), together with superior reproducibility, stability and anti-interference. This developed composite material as a flexible sensing platform can be used to detect PAT in real samples with a satisfactory recovery.

Boron carbide decorated tungsten disulfide nanosheet composite for determination of chloramphenicol in food and pharmaceutical samples

Making the nanocomposites of metal oxides or metal sulfides with carbon source materials has a huge impact on the electrochemical determination of toxic chemicals. To determine the adverse side effects of the antibiotics, electrochemical sensors have been used as they can peek into the sensitivity of the drug sample. This work has done the sensitive amperometric evaluation of a chloramphenicol antibiotic by modifying the electrode of tungsten disulfide decorated boron carbide. Here, tungsten disulfide (WS2) nanosheets and boron carbide (B4C) materials were synthesized by conventional methods which give a good amount of yield. The composite was prepared by the green and cost-effective sonochemical approach with good morphology. The conductivity of the nanocomposite and the response to chloramphenicol were determined by cyclic voltammetry. The sensitivity, limit of detection (LOD), and the linear range were observed by the highly sensitive amperometric technique. From the amperometric analysis, the prepared nanocomposite shows nominal LOD as a 17.4 nM, a broad linear range (0.025–1134.6 µM), and good sensitivity of 1.52 µA µM−1 cm−2. Practicability of the modified sensor was studied in food and pharmaceutical samples with adequate recovery performances. Moreover, the modified electrode shows good stability, repeatability, reproducibility, and anti-interfering properties against the array of food and biological interferences.

Stencil-printed electrode using conductive graphite-based ink: a cost-effective approach for electrochemical determination of dipyrone

Stencil-printed electrode using conductive graphite-based ink: a cost-effective approach for electrochemical determination of dipyrone

A novel nanozyme doped ZnO/r-GO-based sensor for highly sensitive electrochemical determination of muscle-relaxant drug: cyclobenzaprine HCl.

A nanocomposite of Ce-doped ZnO/r-GO was synthesized using a conventional hydrothermal method. The synthesized nanocomposites were utilized for the purpose of sensitive and selective detection of cyclobenzaprine hydrochloride (CBP). The properties of the composite were extensively analyzed, including its morphology, structure, and electrochemical behavior. This study investigates the application of a modified glassy carbon electrode for the detection of CBP, a muscle relaxant used to treat musculoskeletal diseases that cause muscle spasms. The electrode is modified with Ce-doped ZnO/r-GO. Various detection methods, such as cyclic voltammetric and square wave techniques (SWV), were utilized. The composite material showed high effectiveness as an electron transfer mediator in the oxidation of CBP. The electrode showed a good response for SWV evaluations in CBP identification, with a minimum detection limit of 1.6 × 10-8M and a wide linear range from 10 × 10-6 M to 0.6 × 10-7 M, under ideal conditions. The rate constant for charge transfer (ks) and the estimation of the electrochemical active surface area were obtained. A developed sensor exhibited desirable selectivity, long-lasting stability, and remarkable reproducibility. A sensor was used to analyze water, human serum, and urine samples, resulting in positive recovery results.

Selective and Sensitive MIP-Based Electrochemical Sensor for the Analytical Determination of Lanreotide

Lanreotide (LAN) is an analog of somatostatin used to treat acromegaly and neuroendocrine tumors. Considering drug toxicity and the lack of sensitive techniques in drug analysis, the development of sensitive analytical methods is of great importance. During this research, a molecular imprinted polymer (MIP) based film [P(HEMA-MAGA)@MIP/GCE] was prepared by photopolymerization technique for electrochemical determination of LAN for the first time. N-methacryloyl-L-glutamic acid (MAGA) and hydroxyethyl methacrylate (HEMA) were used as functional and basic monomers, respectively. The surface alterations were investigated using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) and the chemical composition of the MIP-based sensor. Theelectrochemical characterization of the modifiedelectrodes was assessed using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Using differential pulse voltammetry (DPV) in standard solution and spiked serum sample of LAN, the linear response range for LAN was obtained as 1.0x10 − 14 M – 1.0x10 − 13 M. The limit of detection (LOD) values were 1.76x10 − 15 M and 1.82x10 − 15 M in water and commercial human serum, respectively. The limit of quantitation(LOQ) values for these were 5.85x10 − 15 M and 6.07x10 − 15 M, respectively. The P(HEMA-MAGA)@MIP/GCE sensor also showed excellent recovery in pharmaceutical preparation and commercial human serum form with of 99.37 % and 99.27 %, respectively, with a good RSD value (0.51–0.73), confirming the accuracy and precision of the sensor. As a control, the non-imprinted polymer (NIP) was also prepared to serve in the same way but without the template. The selectivity experiments were conducted using somatostatin (SOM) and octreotide (OC) as potential competitors to demonstrate the selectivity of the proposed sensor against LAN molecules.

A green route for the synthesis of sponge-like Pr6O11 nanoparticles and their application for the development of chlorambucil sensor

Herein, to fabricate the sponge-like praseodymium oxide nanoparticles (SL- Pr6O11 NPs), a facile and quick sonochemical route is introduced utilizing an environmentally friendly capping agent (Vitis vinifera juice) for the first time. Investigation of the electrochemical behavior of chlorambucil (CHB) showed that the reaction at the surface of the electrode is a diffusion-controlled procedure and the value of the diffusion coefficient (D) was calculated to be 1.35 × 10-5 cm2/s. The suitable electrochemical performance of the Pr6O11 nanoparticles (NPs) enhanced the sensitivity of the sensor for the electrochemical determination of CHB. The sensor signal was linearly proportional to CHB concentration in the range of 8 nM to 220 μM with a detection limit of 1.88 nM under the optimum experimental conditions. Additionally, CHB tablets, human urine and serum samples were successfully used as real samples to detect CHB at SL-Pr6O11/SPE with good recoveries.

A green perspective for the first electrochemical detection and application of balsalazide via recycled waste core-shell carbon/CdO nanoparticles-based hybrid nanosensor

In this report, a glassy carbon electrode (GCE) modified with carbon-based core–shell structures (CSC) with CdO nanoparticles has been prepared and performed for the electrochemical detection of Balsalazide (BLZ). The electrochemical investigation of BLZ was carefully examined using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) on the bare GCE, and CSC-CdO/GCE. Compared to bare GCE, the proposed CSC-CdO/GCE sensor can remarkably enhance the electrocatalytic activity towards the oxidation of BLZ with an increase in the anodic peak currents. For the optimum of experimental conditions, the influence of supporting electrolyte, the pH, concentration of the nanosensor, and scan rate on the peak potentials and current were investigated on the current response of BLZ before the electrochemical determination of BLZ in commercial human serum and urine samples for GCE, and CSC-CdO/GCE. The limit of detection (LOD) for BLZ in the linear range of 8.00 × 10−9 – 8.00 × 10−5 mol/L was determined as 2.20 × 10−9 mol/L. Recovery measurements assessed the accuracy of the proposed sensor in serum and urine samples. The developed sensor indicated high sensitivity and great stability toward BLZ. Core-shell structures are frequently preferred in sensor applications due to their perfect shapes, active catalytic sites, rapid interfacial transport of pores at different length scales, and their ability to reduce or shorten diffusion action paths. CSC was used as a modification material in this study due to its superior properties and advantages. Since CSC has a high surface area during the electron transfer process, it enables more efficient charge transfer between the electrode and the electrolyte. In the study, CdO nanoparticle modification on the CSC was ensured for a synergistic effect to enhance the surface area, electroactivity, and selectivity. After morphological, physical, and chemical characterization of composite material, electrochemical experiments showed that it is extremely promising because of its wide linear concentration range, low LOD, and nearly no interference with some interfering compounds and ions.

A new sensitive layer based on clcinated Zn/Ti-MOF/magnetic molecularly imprinted polypyrrole: Application to preconcentration and electrochemical determination of perfluorooctane sulfonic acid by magnetic carbon paste electrode

In this research, a new approach based on magnetic electrodes has been developed for the determination of per-fluorooctane sulfonic acid (PSOF). Zinc and Titanium-based Metal-organic framework (MOF) was synthesized and used with polypyrrole as a conductive polymer for preparation of the absorbent to achieve the best performance for electrochemical application. The response of the electrode for determination of the PFOS was affected and optimized by different factors such as buffer solution, pH of the solution, amount of absorbent, extraction time of absorbent, accumulation time, as well as the Square Wave Voltammetry (SWV) instrumental parameters including voltage step, pulse amplitude, frequency and resting time. In the optimum condition, the response of the Zn/Ti/C-MOF-magnetic molecular imprinting polymer/carbon paste electrode (MOFMMIP/CPE) has increased logarithmically by increasing the concentration in the range of 0.002–165 μM by the limit of detection (LOD) of 0.7 nM. The obtained percentage of Recovery (96.00–104.14 %), Bias (–4.00 - 4.14 %) and Relative Standard Deviation (RSD) (1.89–3.74 %) for determination of the PFOS in real and spiked tap water, river water and well water samples demonstrates that the proposed method has an acceptable precision. The comparison between the gained data by the presented method and High-performance liquid chromatography (HPLC) showed that the presented method has high accuracy.

Eco-friendly synthesis of cluster-like Dy2Ce2O7 nanoparticles using orange juice and their application in electrochemical determination of isoniazid

In this study, cluster-like (CL) Dy2Ce2O7 nanoparticles were synthesized via an easy and rapid sonochemical pathway. X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM) were used for the characterization of nanoparticles. The construction of an electrochemical sensor was performed to determine isoniazid (IZN) based on ionic liquid (IL) and the cluster-like nanostructure of Dy2Ce2O7 modified carbon paste electrode (CL-Dy2Ce2O7/IL/CPE). Using the fabricated sensor, cyclic voltammetry (CV) along with differential pulse voltammetry (DPV) have been utilized to examine the catalytic activity of the modified electrode toward oxidation of IZN in 0.1 M phosphate buffer solution (PBS) with pH of 7.0. The large specific surface area and electrocatalytic properties of CL-Dy2Ce2O7 as well as the good electrical conductivity of ionic liquid greatly enhanced the current signal of the IZN at the CL-Dy2Ce2O7/IL/CPE. The process at the surface of the electrode was under the diffusion control mechanism and the diffusion coefficient for IZN was 1.08 × 10−5 cm2/s. Additionally, with a low detection limit of 9.0 nM, the peak current of IZN rose linearly with concentration in the range of 0.02–340.0 μM. Our findings demonstrate that the sensitive and selective detection of IZN in pharmaceutical and biological samples can be achieved using the CL-Dy2Ce2O7/IL/CPE.