Oxide Modified Carbon Paste Electrode Research Articles

Electrochemical determination of uric acid in presence of folic acid using synthesized cobalt oxide modified carbon paste electrode

Here, the synthesis of CoO nanoparticle by using co-precipitation method and characterized by XRD, SEM and EDAX techniques. The CoO nanoparticle used as modified carbon paste electrode for sensing the UA in presence of FA. The CoO/MCPE shows the excellence sensitivity towards the determination of both UA and FA. The kinetic electron transfer study of UA and FA shows with good linearity and both electrodes showed adsorption electrode process. The limit of detection (LOD) and limit of quantification (LOQ) was found to be 3.32 µM and 11.1 µM for FA and 6.09 µM and 20.3 µM for UA, respectively. The CoO/MCPE applied for the simultaneous electrochemical determination of UA and FA, the proposed method was used for real sample analysis.

Challenging electroanalytical method for the determination of mirabegron in biological samples and pharmaceutical formulations

A simple, economic, sensitive, and time-saving differential pulse voltammetric (DPV) procedure using nanostructured zinc oxide modified carbon paste electrode (nano ZnO-CPE) in conjunction with an anionic surfactant sodium dodecyl sulfate (SDS) was developed for ultra- sensitive detection of mirabegron (MIR), the most prescribed pharmaceutical drug in treatment of overactive bladder (OAB). The use of nanostructured zinc oxide CPE modifier increased the electrode active surface area as well as improved the process of electron transfer, also it was found that at optimal conditions MIR electrochemical process was both irreversible and diffusion-regulated. The morphological characterization of the fabricated electrode was performed using field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDX). MIR voltammetric behavior was investigated using Nano ZnO-CPE in different content and electrode compositions. Therefore, ultra-sensitive results were attained with a linearity range of (0.55 to 100.20 ng ml−1) and a low limit of detection (LOD) of 0.51 ng ml−1 and limit of quantification (LOQ) of 1.54 ng ml−1 in a 0.04 M Britton-Robinson (BR) buffer at an adjusted pH of 6.0 with scan rate 100 mV s−1. Furthermore, the proposed approach was successful in measuring MIR with acceptable percentage recoveries (99.81–100.11 %) in pharmaceutical dosage form and varying concentration ranges in biological samples (99.74–100.35 %). The proposed method has been validated using ICH criteria and proven to be accurate and repeatable.

Electrochemical activation of zinc oxide decorated graphene oxide modified carbon paste electrode surface for investigation of bisphenol-A and sulfadiazine: A voltammetric study

The rapid monitoring of drugs has robust global desire for environment has high efficacy. In this study the Zinc Oxide/Graphene Oxide modified carbon paste electrode (ZnO/GO/MCPE) was used for the voltammetric determination of Bisphenol-A (BPA) and Sulfadiazine (SFZ). The characterization of synthesized ZnO NP’s done by XRD, SEM and EDX technique; the morphological character of procured graphene oxide is done by SEM and ZnO/GO/MCPE brings the tremendous sensitivity towards the detection of BPA and SFZ utilizing CV and LSV techniques. The pH, concentration and scan rate parameters investigation were performed for BPA and SFZ, the ZnO/GO/MCPE is employ for SFZ and BPA in simultaneous determination. the limit of detection was established to be 0.209 µM and 2.760 µM respectively.

Electrochemical Detection of Dopamine in the Presence of Uric Acid at Cerium Oxide and L-Tyrosine Mixture Modified Carbon Paste Electrode: A Cyclic Voltammetry Study

In the present work, we are prepared a simple is sensitive and selective for Cerium oxide L-Tyrosine modified carbon paste electrode (CeO2 - L-TMCPE) for the simultaneous examination of Dopamine (DA) and Uric Acid (UA), by using cyclic voltammetry (CV). Carbon paste electrode was fabricated with Cerium oxide L-Tyrosine mixture as modifier for the detection of DA in the presence of UA in 0.2 M Phosphate buffer solution of pH 7.0. The CeO2 - L-TMCPE MCPE display an increase in the peak (Ip) current as related to that of BCPE. The CeO2 - L-TCPE mixture MCPE showed outstanding electro catalytic action for selective determination of DA in the presence of UA. Surface morphology of CeO2NPs was studied using XRD, SEM and EDAX, some electrochemical constraints alike effect of pH, effect of Scan rate, varied concentrations DA & UA were considered at CeO2 - L-TMCPE MCPE. The modified CeO2 - L-TCPE behaves similar selective electrochemical sensor for finding of DA and UA.

Green and sustainable synthesis of CaO nanoparticles: Its solicitation as a sensor material and electrochemical detection of urea

Urea is recognized as one of the most frequently used adulterants in milk to enhance artificial protein content, and whiteness. Drinking milk having high urea concentrations which causes innumerable health disputes like ulcers, indigestion, and kidney-related problems. Therefore, herein, a simple and rapid electroanalytical platform was developed to detect the presence of urea in milk using a modified electrode sensor. Calcium oxide nanoparticles (CaO NPs) were green synthesized and used as a catalyst material for developing the sensor. Synthesized materials formation was confirmed by different techniques like FTIR, UV–visible, XRD, SEM–EDX, and Raman spectroscopy. The carbon paste electrode (CPE) was modified using the CaO NPs and used as a working electrode during the analysis followed by cyclic voltammetry and differential pulse voltammetry (DPV) techniques. The fabricated calcium oxide modified carbon paste electrode (CaO/CPE) successfully detected the presence of urea in the lower concentration range (lower limit of detection (LLOD) = 0.032 µM) having a wide linear detection range of 10–150 µM. Adsorption-controlled electrode process was achieved at the scan rate variation parameter. The leading parameters like the selectivity, repeatability, and stability of the CaO/CPE were investigated. The relative standard deviation of sensor was ± 3.8% during the interference and stability study.

Zinc oxide modified carbon paste electrode sensor for the voltammetric detection of L-tryptophan in presence of uric acid and ascorbic acid

The mechanochemical method was used for the synthesis of Zinc oxide nanoparticles (ZnONps) and was characterized by energy-dispersive spectroscopy (EDAX) scanning electron microscopy (SEM) and X-ray diffraction (XRD). Using a zinc oxide modified carbon paste electrode (ZnOMCPE) the oxidative response of L-tryptophan (LTP) was analyzed by differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques. CV was used to scrutinize the parameters of pH, concentration and scan rate of LTP. In this work, compared to bare carbon paste electrode (BCPE), the modified electrode shows enhanced peak current. CV exhibits a good linearity in the concentration range 10–40 μM (LTP). The limit of detection (LOD) and limit of quantification (LOQ) values of LTP were observe to be 0.57 and 1.72 μM respectively. DPV was used to study the analytical individualization and interference study of L-tryptophan (LTP), Uric acid (UA) and Ascorbic acid (AA). The above outcome shows that the polished surface of the modified electrode gives excellent sensitivity and selectivity in its voltammetric response and good LOD for LTP.

Electrochemical aptasensor based on carboxylated graphene oxide modified carbon paste electrode for strontium ultrasensitive detection

Determination of strontium ions (Sr2+) is crucial with regard to human health and environmental protection. In this work, an electrochemical aptasensor was designed using carboxylated graphene oxide (CGO)-modified carbon paste electrode (CGO/CPE) for ultrasensitive determination of Sr2+ ions. The electrochemical determination was accomplished with employing the constructed G-quadruplex (G4) aptamer at the surface of aptasensor in presence of carmoisine (CA) as an electrochemical label. Moreover, NH2-functionalized aptamer was immobilized onto CGO/CPE via carboxylic group. Hence, differential pulse voltammetry was applied for detection of any possible signal changes of CA on the aptasensor surface. The reduction peak currents of CA in the absence and presence of Sr2+ in solution were different and this difference was linearly dependent to the concentration of Sr2+ in solution. The analytical results revealed that our novel aptasensor showed two appropriate linear ranges (0.1–8.0 pM and 3.0–20.0 nM) versus to Sr2+ ion concentrations with the limit of detection of 0.06 pM (S/N = 3). Excellent stability, selectivity and reproducibility were achieved with this new electrochemical aptasensor. Additionally, the aptasensor showed good achievements in analysis of Sr2+ in aqueous and urine real samples, which making this proposed method a promising candidate for electrochemical detection of Sr2+ in real samples.

Electrochemical detection of bisphenol A in presence of catechol and hydroquinone at copper oxide modified carbon paste electrode

Utilizing co-precipitation method copper oxide (CuO) nanomaterials are prepared and analyzed using X-ray diffraction (XRD), Scanning electron microscope (SEM), and Energy-dispersive X-ray Analysis (EDAX) technique. Copper oxide modified carbon paste electrode (CuOMCPE) were used as electrochemical sensor for the study of catechol, bisphenol A and hydroquinone using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The analyte species shows high reproducibility in voltammetric response because of his enhancement. The CuOMCPE exhibits the better electrocatalytic property for the oxidation of BPA, CC and HQ. Parameters like scan rate and concentration of Bisphenol A (BPA), catechol (CC) and hydroquinone (HQ) were studied by CuOMCPE. The effect of scan rate on CuOMCPE was studied individually for BPA, CC, and HQ and shows that the electrode process was adsorption-controlled. The modifier exhibits good limit of detection (LOD) and limit of quantification (LOQ) values are found at 2.48 μM and 8.26 μM for BPA, 3.22 μM and 10.73 μM for CC, 4.94 and 16.48 μM for HQ respectively. The CuOMCPE shows high stability and reproducibility compared to BCPE. DPV were studied using CuOMCPE gives three well defined peaks located at 0.4406(BPA), 0.1043 V (CC) and 0.0075 V (HQ) respectively. The simultaneous and interference study of analytes were studied using CuOMCPE. Hence, the modifier exhibits good selectivity and sensitivity for the study of BPA, HQ and CC.

Graphene oxide modified H4L‐ion imprinting electrochemical sensor for the detection of uranyl ions

AbstractThe rapid development of the nuclear industry has gradually aroused people′s attention to the problem of nuclear pollution. Due to the biological toxicity of uranium and its aqueous solution, simple and rapid detection of uranium in the water environment is quite important. An ion imprinted carbon nanomaterial (graphene oxide) electrochemical sensor for the detection of trace uranyl ions was prepared by using the synthesized bipolar tetradentate macrocyclic uranyl ligand cyclo‐bis‐phenylenediamine‐bis‐(phenylmethyl‐diphyrrolecarbaldehyde) (H4L) as functional monomer. The sol‐gel polymer was prepared by hydrolysis and polymerization of H4L ligand, 3‐aminopropyltrimethoxysilane and tetraethoxysilane. H4L‐ion imprinted polymer (U‐IIP) was prepared by adding 1 mM uranyl ion as template ions. Then the polymer was bonded to graphene oxide modified carbon paste electrode, and the template ions were eluted to obtain H4L‐ion imprinted‐graphene oxide modified carbon paste electrode (U‐IIP/GO/CPE). Differential pulse voltammetry was used to detect trace uranyl ions. The results showed that the U‐IIP/GO/CPE sensor system can detect uranyl ions with high sensitivity and specificity, and the peak current appeared around −0.26v. In the range of 0.01 μM∼3.0 μM, the detection current had a good linear relationship with the molar concentration of uranyl ions, and the method detection limit was 1.32 nM (S/N=3). Through the detection of actual samples, it had a good acceptable recovery rate (95.45 %∼106.25 %), and the relative standard deviation was less than 3.25 %.

Electrochemical activation of copper oxide decorated graphene oxide modified carbon paste electrode surface for the simultaneous determination of hazardous Di-hydroxybenzene isomers

The construction of a consistent electrochemical sensor is essential for the determination of hazardous pollutants in water and environments. Hydroquinone (HQ), catechol (CT), and resorcinol (RS) frequently coexist as priority pollutants in water and interfere with each other during identification, which poses a challenge for simultaneous and sensitive determination for those di-hydroxybenzene isomers. In this work, copper oxide (CuO) decorated graphene oxide (GO) nanocomposite (CuO/GO) was prepared and used to modify carbon paste electrode (CPE). The as-prepared electrode (CGCPE) was electrochemically activated in the presence of NaOH solution (Et-CGCPE) for the simultaneous determination of di-hydroxybenzene isomers (HQ, CT, and RS), and showed a well-defined oxidation peak with a significantly improved electrochemical response. We ascribe this high performance to the formation of electroactive functional groups on the electrode surface during the electrochemical activation and the synergistic effect between GO and CuO. Under the optimized conditions, the results show a long linear concentration range of HQ (0.2–360 µM), CT (0.3–360 µM), and RS (0.7–250 µM) with the detection limits of 1.0 μM, 1.1 μM, and 1.8 μM, respectively. The Et-CGCPE was effectively applied to detect three di-hydroxybenzene isomers in lake water with good repeatability and stability.

A Novel Reduced Graphene Oxide Modified Carbon Paste Electrode for Potentiometric Determination of Trihexyphenidyl Hydrochloride in Pharmaceutical and Biological Matrices.

A novel promising carbon paste electrode with excellent potentiometric properties was prepared for the analysis of trihexyphenidyl hydrochloride (THP), the acetylcholine receptor and an anticholinergic drug in real samples. It contains 10.2% trihexyphenidy-tetraphenylborate ionic pair as the electroactive material, with the addition of 3.9% reduced graphene oxide and 0.3% of anionic additive into the paste, which consists of 45.0% dibutylphthalate as the solvent mediator and 40.6% graphite. Under the optimized experimental conditions, the electrode showed a Nernstian slope of 58.9 ± 0.2 mV/decade with a regression coefficient of 0.9992. It exhibited high selectivity and reproducibility as well as a fast and linear dynamic response range from 4.0 × 10−7 to 1.0 × 10−2 M. The electrode remained usable for up to 19 days. Analytical applications showed excellent recoveries ranging from 96.8 to 101.7%, LOD was 2.5 × 10−7 M. The electrode was successfully used for THP analysis of pharmaceutical and biological samples.

Graphene Oxide Modified Carbon Paste Electrode for Handy and Ultra‐sensitive Determination of Epinephrine in the Presence of Uric and Ascorbic Acids

AbstractA precise and sensitive electrochemical sensor based on a simple graphene oxide modified carbon paste electrode (GO/CPE) was successfully fabricated for simultaneous detection of epinephrine (EPN), uric acid (UA), and ascorbic acid (AA). The GO/CPE displays better electrochemical activity towards EPN by largely improving the current sensitivity and selectivity. Large peak separation allowed this sensor to analyze EPN individually and simultaneously in the mixture of AA and UA. The developed sensor showed good reproducibility, and stability. The sensor exhibited acceptable performance in wide concentration range (0.1–2000 μM) with a limit of detection down to 50 nM.

A reliable electrochemical sensor for detection of catechol and hydroquinone at MgO/GO modified carbon paste electrode

Herein, report a reliable, potent and more sensitive electrochemical sensor for the selective investigation of hydroquinone (HQ) and catechol (CC) at magnesium oxide and graphene oxide modified carbon paste electrode (MgO/GO/MCPE). The prepared MgO nanoparticle was confirmed by X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray (SEM–EDX). The constructed electrode provides high current reaction with low detection limit for CC (0.45 µM) and HQ (0.37 µM). The effect of pH, sweep rate, concentration was carried electrochemically. The fabricated MgO/GO/MCPE depicts electrode process was adsorption controlled and gave fine electrocatalytic activity towards simultaneous electrochemical analysis of CC and HQ. The MgO/GO/MCPE exhibits excellent stability with fine selectivity and sensitivity. The analytical testing of modified electrode has been analysed in tap water sample as real sample with acceptable recovery.

Preparation, characterization and simultaneous electrochemical detection toward Cd (II) and Hg(II) of a phosphate/zinc oxide modified carbon paste electrode

The nanoparticle ZnO-NP was manufactured by doping natural phosphate (NP) with zinc. The resulting sample was characterized by different techniques such as DRX, FT-IR, SEM. The ZnO-NP/CPE electrode has been applied for the simultaneous determination of Cd (II) and Hg (II). The electrochemical measurement of the elaborate sensor toward the hazardous metals ions was investigated by cyclic voltammetry (CV), and square wave voltammetry (SWV). The response of the electrochemical sensor indicates that the ZnO-NP/CPE electrode show a high performance electro analysis for Cd (II) and Hg (II). The suggested ZnO-NP electrode CPE has a linear straight line from 4.2 −21 µM and a lower detection limit (3σ) 4.2 for Cd (II) and 2.9 nM for Hg (II) under optimized experimental conditions. The elaborated sensor has been utilized with success for the simultaneous analysis of Cd (II) and Hg (II) in drinking water, and good results were achieved.

An Electrochemical Sensor Based on Reduced Graphene Oxide Modified Carbon Paste Electrode for Curcumin Determination in Human Blood Serum

An Electrochemical Sensor Based on Reduced Graphene Oxide Modified Carbon Paste Electrode for Curcumin Determination in Human Blood Serum

Voltammetric detection of caffeine in pharmacological and beverages samples based on simple nano- Co (II, III) oxide modified carbon paste electrode in aqueous and micellar media

Caffeine (Caf) is one of the most widespread compounds in food components, beverages and medicines, which drives us to find a simple, fast and convenient method for its determination. The promising Nano-Cobalt (II, III) oxide modified carbon paste (NCOMCP) sensor was fabricated and applied to the sensitive determination of Caf in both aqueous (0.01 mol L−1 H2SO4) and micellar media (0.5 mmol L−1 sodium dodecylsulfate, SDS). Surface characterization was performed utilizing scanning electron microscopy (SEM) and energy dispersive analysis of X-rays (EDX). The electrochemical behavior of Caf was studied by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA). From these experiments, the apparent diffusion coefficient (Dapp) and catalytic rate constant (kcat) were evaluated to be 4.2 × 10-5 cm2 s-1 and 1.92 × 103 mol−1 L-2 s-1, respectively. Caf can be detected in a concentration range between 5.0 and 600 μmol L−1, with a limit of detection (LOD) of 0.016 μmol L−1, as determined from the calibration plot obtained using differential pulse voltammetry (DPV). The sensor was applicable for Caf sensing in several commercial real samples with recoveries ranging from 98.9% to 101.9%. It exhibited good selectivity in the presence of common interferences.

Designing an Au/reduced graphene oxide modified carbon paste electrode for the electrochemical quantification of agnuside

Agnuside despite its good properties for the body, can be harmful to the kidneys in extra concentrations. So, its measurement is important. For the first time, we developed a simple, rapid and inexpensive method for the investigation of agnuside electrochemical behavior by designing a gold/reduced graphene oxide/carbon paste electrode (Au/RGO/CPE). The Au/RGO nanocomposite was synthesized through a one-pot in situ reduction of graphene oxide (GO) and HAuCl4 in the presence of sodium citrate and the obtained product was studied by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The anodic oxidation of agnuside has been carried out at a modified carbon paste electrode in 0.1 M phosphate buffer solution (pH 6.0) using sensitive differential pulse voltammetry (DPV). Several parameters such as the type and pH of supporting electrolyte and scan rates were optimized. This study reported a good linearity in the range of 0.050–250.0 nM and a low detection limit of 0.016 nM. The relative standard deviations (RSDs) for 10.0 nM and 100.0 nM of agnuside were obtained 3.3% and 1.2%, respectively. The sensor was successfully applied to determine agnuside in Vitex agnus castus fruit and urine sample.

Electro oxidation and analytical applications of valacyclovir at reduced graphene oxide modified carbon paste electrode

Abstract Electrochemical investigation of valacyclovir (VCH), an antiviral drug was investigated at carbon paste sensor modified with reduced graphene oxide (rGO/CPE). Cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques are inherited to determine the electrochemical behavior of VCH. Modified and bare carbon surfaces were characterized by Atomic force microscope (AFM). The technique dependence on current, potential, supporting electrolyte pH, concentrations, sweep rate, and excipients were evaluated to optimize the experimental conditions. Contrasted with prior reports, this study is very impressive on account of modifiers utilized and expedient because of its affectability, selectivity and LOD value.

Electrochemical behavior of mefenamic acid at graphene oxide modified carbon paste electrode

Abstract Graphene oxide mixed carbon paste electrode was used to look into the electrochemical performance of bio-active drug, mefenamic acid using voltammetry technique. The outcome of effect of pH, accumulation time, concentrations, scan rate, and excipients were studied. Quantitative determination of mefenamic acid conceded using highly sensitive differential pulse voltammetric method. The detection limit was found to be 0.95 nM for the concentration range 7.0 x 10-7 M to 1.0 x 10-10 M. A possible equal number of electron and proton found mechanism of electrochemical oxidation of mefenamic acid was proposed, and activation parameters ΔH≠ = 26.56 kJ mol-1, ΔS≠ = -248.7J K-1 mol-1, Ea = 29.04 kJ mol-1 were determined.

Electro oxidation and analytical applications of nimesulide at graphene oxide and reduced graphene oxide modified carbon paste electrode

Abstract Electrochemical analysis of bio-active drug nimesulide (NIM) has been examined at carbon paste electrode using modifiers graphene oxide and reduced form of graphene oxide modified (GO/CPE & rGO/CPE) by voltammetry techniques. Effect of various parameters pH, concentrations, varying scan rates, and interfering agents were considered. Linear relation between peak potential, peaks current, scan rate, temperature, heterogeneous constant, concentration variation was attained. Different voltammetric techniques were utilized to study the application part of the proposed sensors, such as differential pulse voltammetry (DPV) and square wave voltammetry (SWV). The linear response was observed in the range of 300 to 0.1nM with a detection limit of 11.20 nM (DPV) 1.08 nM (SWV) at GO/CPE and 1.03 nM (DPV) and 0.1nM (SWV) at rGO/CPE. A probable mechanism of electrochemical oxidation of NIM was proposed, and activation parameters such as Ea = 21.12 kJ mol-1, ΔH≠ = 18.64 kJ mol-1, ΔS≠ = -299.7 J K-1mol-1 and ΔG≠= 70.67 kJ mol-1, were determined.