Electrochemical Sensor For Selective Detection Research Articles

Preparation of molecularly imprinted electrochemical sensors for selective detection of hydroxyl radicals based on reduced graphene oxide nanosilver (rGO/AgNPs) composites

An electrochemical sensor for selective detection of hydroxyl radicals (OH) has been developed, which is based on silver nanoparticles and reduced graphene oxide composites (rGO/AgNPs) synthesized in situ by the green reduction method, combined with the electrochemical polymerization method for preparation of molecularly imprinted polymers (MIPs) to modify the screen-printed electrodes. During the assay, the concentration of hydroxyl radicals was obtained by capturing the product 2,5-dihydroxybenzoic acid (2,5-DHBA). Under the optimal experimental conditions, the oxidation peak currents of the target 2,5-DHBA by differential pulse voltammetry (DPV) and its concentration showed a good linear relationship in the concentration ranges of 0.1 ∼ 0.5 μM and 1 ∼ 100 μM, with the limit of detection (LOD) of 0.021 μM. Interference experiments and other studies were also carried out, and the results showed that the sensor has good reproducibility, stability, and selectivity, and the comparison of the detection results with the conventional detection method, high-performance liquid chromatography, indicated the accuracy of the sensor detection, which is a convenient, sensitive, and efficient method for the detection of hydroxyl radicals.

Biomimetic imprinted electrochemical sensor for selective detection of streptomycin residue in milk

A novel imprinted electrochemical sensor for streptomycin recognition was developed by using the electrodes decorated with graphene oxide (GO) and chitosan (CS) composites. Molecularly imprinted polymer (MIP) was synthesized by electropolymerization with streptomycin (STR) as the template, and 3-aminophenylboronic acid (APBA) and aniline (AN) as the monomers. The fabrication procedure was studied and optimized along with a number of affecting factors. Scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR) were used to analyze the imprinted sensor. Electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and cyclic voltammetry (CV) were used to evaluate the recognition performance of the sensor. Under the optimized conditions, a linear range of the sensor from 2.0 × 10−10 mol/L to 1.0 × 10−6 mol/L was calculated with the detection limit of (LOD) 2.54 × 10−13 mol/L. High binding affinity and selectivity for the template STR were displayed by the molecular imprinted sensing interface. The proposed sensor was successfully used to rapidly and accurately detect STR in milk samples with recoveries from 89.46% to 101.2%. It also demonstrated satisfactory repeatability, stability and regeneration capacity. This study not only serves as a valuable reference for other related research, but also has great significance for food safety inspection.

Copper oxide nanoflowers/poly-l-glutamic acid modified advanced electrochemical sensor for selective detection of l-tryptophan in real samples

The main objective of this research work is to develop a low-cost sensor to detect l-tryptophan (L-tryp) in real sample medium based on a modified glassy carbon electrode. For this, copper oxide nanoflowers (CuONFs) and poly-l-glutamic acid (PGA) were used to modify GCE. The prepared NFs and PGA coated electrode was characterized using field emission scanning electron microscope (FE-SEM) with energy dispersive X-ray (EDX) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Furthermore, the electrochemical activity was performed by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The modified electrode showed excellent electro-catalytic activity towards L-tryp detection in PBS solution at neutral pH 7.0. Based on the physiological pH condition, the proposed electrochemical sensor can detect L-tryp concentration with a linear range of 1.0 × 10−4-8.0 × 10−8 molL−1 with having a detection limit of 5.0 × 10−8 molL−1 and sensitivity of 0.6μA/μMcm2. The selectivity of L-tryp was tested with a mixture of salt and uric acid solution at the above conditions. Finally, this strategy demonstrated excellent recovery value in real sample analysis like milk and urine.

NanoMIPs-based electrochemical sensors for selective detection of amphetamine

A highly sensitive and portable electrochemical sensor based on molecularly imprinted nanoparticles (nanoMIPs) was developed.NanoMIPs were computationally designed for specific recognition of amphetamine, and then synthetized using solid phase synthesis. NanoMIPs were immobilized onto screen-printed carbon electrodes using a composite film comprising chitosan, nanoMIPs, and graphene oxide.Ferrocenylmethyl methacrylate was incorporated in nanoMIPs allowing electrochemical detection. The signal recorded for the electrochemical oxidation of ferrocene has proven to be dependent on the presence of amphetamine interacting with nanMIPs. The sensor was tested successfully with street samples, with high sensitivity and satisfactory recoveries (from 100.9% to 107.6%). These results were validated with UPL-MS/MS. The present technology is suitable for forensic applications in selective determination of amphetamine in street samples.

Retraction Note to: Crystalline growth of tungsten trioxide (WO3) nanorods and their development as an electrochemical sensor for selective detection of vitamin C

Retraction Note to: Crystalline growth of tungsten trioxide (WO3) nanorods and their development as an electrochemical sensor for selective detection of vitamin C

An Electrochemical Sensor for Selective Detection of Cu2+ by using a self-Assembled Cu Coordinated β-cyclodextrin- nitrogen-Doped Carbon Quantum Dots Composite

Nitrogen-doped carbon quantum dots (N-CQDs) were synthesized by one-step hydrothermal method using citric acid as carbon source and urea as nitrogen source. β-cyclodextrin (β-CD) is a cyclic oligosaccharide with a unique hollow structure, which is beneficial to the enrichment of metal ions on the electrode surface while reducing the agglomeration of carbon quantum dots and maintaining conductivity. When Cu2+ is coordinated with β-CD, it can further increase the affinity for Cu2+ and recognize Cu2+ more sensitively. Therefore, we coordinated Cu2+ and β-CD to form copper ion coordinated β-cyclodextrin (Cu-β-CD). By self-assembly, the prepared N-CQDs and Cu-β-CD combined to form Cu-β-CD/N-CQDs composites. The electrochemical sensor constructed by Cu-β-Cd/N-CQDs successfully realizes the selective detection of Cu2+ in the range of 1–125 μmol l−1, and the lowest detection limit is 0.094 μmol l−1. In the detection of actual water samples, the Recovery of Cu2+ was between 92% and 120%, and the RSD was between 2.3% and 5.2%. Therefore, Cu-β-CD/N-CQDs composite is expected to be constructed as a non-toxic, pollution-free electrochemical sensor for selective detection of heavy metal Cu2+ ions in water.

Electrochemical Sensor for Selective Detection of Meldonium in Urine by Voltammetry

AbstractA highly sensitive electrochemical sensor based on arenediazonium tosylates was designed to detect meldonium in urine. The effect of the concentration of ArN2+OTs− arenediazonium tosylate modifier and various substituents was studied. Basic operating parameters for voltammetric meldonium detection were established and the procedure for urine sample preparation was developed. The following values were obtained: limit of detection (LOD) 0.005 mg ⋅ L−1 (P=0.95) and limit of quantification (LOQ) 0.01 mg ⋅ L−1. The relationship between the analytical signal and meldonium concentration in the solution ranging from 0.01 to 400 mg ⋅ L−1 was described by a linear function. The meldonium concentration error did not exceed 18 %. The analysis time for a single urine sample was reduced to 15 minutes.

A green synthesis route to develop molecularly imprinted electrochemical sensor for selective detection of vancomycin from aqueous and serum samples

• Fabrication of a green sensor for the analysis of vancomycin. • Green synthesis of TiO 2 nanoparticle incorporated alginate molecularly imprinted polymer for the design of the electrochemical sensor. • Real sample analysis in spiked serum and tap water samples with good accuracy. • A highly sensitive and selective method with an LOD value of 2.808 pM in the linear range of 0.01–0.1 nM. Developing rapid, cost-effective, and "green" approaches to achieve environmental sustainability is currently one of the most important issues for addressing water pollution problems. This study presents a green process that relies on a sensitive molecularly imprinted electrochemical sensor fabricated on a glassy carbon electrode (GCE) using alginate and TiO 2 to determine vancomycin (VAN). The Alginate@TiO 2 /MIP-GCE sensor was found to show excellent efficiency for target molecule recognition. In the experimental study, parameters such as template: polymer ratio, drying time, dropping volume, removal solution and time, and rebinding time, which affect the sensor response, were optimized. The electrochemical behavior of the designed sensor was investigated using differential pulse voltammetry (DPV). Under optimum conditions, the linear range and limit of detection were found to be 10–100 pM ( r = 0.996) and 2.808 pM, respectively. Satisfactory recovery results were obtained for the determination of VAN in serum and tap water samples. Furthermore, the sensor displayed good repeatability and stability for VAN detection. Finally, Analytical GREEnness Metric Approach and Software (AGREE) was applied to evaluate the greenness profile of our method. The fabricated sensor not only had high selectivity and sensitivity but also was developed via a quite green route in terms of the solvents and methods used throughout the experiment.

A One-Step Electropolymerized Biomimetic Polypyrrole Membrane-Based Electrochemical Sensor for Selective Detection of Valproate.

Bipolar disorder is a chronic mental disease with a heavy social and economic burden that causes extreme mood swings in patients. Valproate is a first-line drug for bipolar disorder patients to stabilize their daily mood. However, an excessive amount of valproate in the blood could induce severe adverse effects, which necessitates the monitoring of blood valproate levels for patients. Here, we developed an innovative electrochemical sensor for selective and simple detection of valproate based on a molecularly imprinted polymer membrane via one-step electropolymerization. Gold nanoparticles were electrochemically modified to the screen-printed electrode under the selective membrane to enhance its conductivity and stability. The successfully fabricated biosensor was characterized by scanning electron microscopy, cyclic voltammetry, and differential pulse voltammetry methods. The binding of the target molecules to the valproate-customized biomimetic polypyrrole membrane blocks cavities in the membrane and alters its electric properties, which can be detected as a decrease in the peak current by differential pulse voltammetry method. The peak current change presents a great log-linear response to the valproate concentration around the therapeutic window. The limit of detection of this method was 17.48 μM (LOD, S/N = 3) and the sensitivity was 31.86 μM μA−1. Furthermore, the biosensors exhibited both satisfying specificity with the interference of other psychological pharmaceutical drugs and uniformity among sensors, indicating their potential and reliability in translational application. This simple and reliable method of sensing valproate molecules primarily provides an exceptional solution to valproate point-of-care testing in clinical practice.

RETRACTED ARTICLE: Crystalline growth of tungsten trioxide (WO3) nanorods and their development as an electrochemical sensor for selective detection of vitamin C

Tungstate nanorods (WO3 -NRs) were synthesized by a facile hydrothermal method using sodium tungstate as a precursor while sodium sulfate and hydrochloric acid were used as stabilizing agents. Scanning electron microscopy (SEM) images showed outstanding growth of WO3-NRs with uniform surface morphology. The X-ray diffraction (XRD) analysis confirmed the purity and crystalline nature of the synthesized material. The material was further characterized by different tools such as TEM, EDX, FTIR, XPS, BET, and Raman spectroscopy. For the electrochemical response of WO3-NRs, cyclic voltammetry measurements were performed for the detection of vitamin C (ascorbic acid). The designed sensor shows a limit of detection of 0.56 µM and higher selectivity in the presence of its structural and functional analogs such as uric acid and lauric acid. Improved sensing properties of WO3-NRs are attributed to the synergistic effects involving the quantum effect, high surface area, fast electron transfer, and highly ordered 1-D nanostructure. Among them, the highly arranged 1-D growth of WO3 nanorods has a greater impact on the efficiency of the biosensor. These results provide a new insight for the synthesis of 1-D nanostructures of transition metal oxides for contributions in sensor devices, solar cells, and capacitor applications.

Screen-printed carbon electrode (SPCE) modified by molecularly imprinted polymer (MIP) nanoparticles and graphene nanosheets for determination of sertraline antidepressant drug

In this paper, a novel molecularly imprinted polymer (MIP) electrochemical sensor for selective detection of an antidepressant drug, sertraline (STR) has been developed. The precipitation polymerization method in the presence of sertraline hydrochloride as template molecules was used for synthesize of MIP nanoparticles. The sensor was developed by embedding a very thin layer of the MIP/graphene suspension on the handmade screen-printed carbon electrodes (SPCEs). The K3 [Fe(CN)6]/K4[Fe(CN) 6] redox couple was used as a probe to characterize the sensor by using cyclic voltammetry & differential pulse voltammetry methods. The sertraline binding experiments indicated that the MIP/graphene modified SPCEs have higher adsorption ability than the non-imprinted polymer(NIP)/graphene modified SPCEs. Factors affecting the sensor response such as composition of MIP/graphene suspension, extraction pH, preconcentration time and stirring rate of sample solution were optimized. Under optimal conditions, the sensor exhibited good sensitivity (177.25 µA L µmol−1) for sertraline with a linear range of 5.0 × 10−9 to 7.5 × 10−7 M (R2 = 0.9971) and detection limit of 1.99 × 10−9 M. The sensor was successfully applied for the determination of sertraline in tablet and human serum samples with recovery values in the range of 97.98–101.33%.

A highly sensitive poly-arginine based MIP as an electrochemical sensor for selective detection of dimetridazole

In this experiment, a highly effective electrochemical sensor based on a molecularly imprinted polymer has been developed for ultrasensitive detection of dimetridazole. The sensor was made by incorporating of dimetridazole as a template molecule during the electropolymerization of poly-arginine on a glassy carbon electrode. The modified electrode GCE/P-Arg@MIP was characterized by voltammetric and microscopic techniques. Differential pulse voltammetry method was used to detect target analyte under the optimum condition. The DPV response to dimetridazole was linear at 0.1×10-9 to 10×10-6molL-1(R2=0.996), with a method detection limit (S/N=3) of 0.1×10-9molL-1. Moreover, the proposed sensor shows satisfactory recovery ranges for the determination dimetridazole in commercially available egg, milk and honey samples.

Electroactive Molecularly Imprinted Polymer for Selective Detection of 4-Nitrophenol

We propose to develop a reusable electro-chemical sensor for selective detection of 4-nitrophenol (4-NP), based on molecularly imprinted polymer (MIP) technology. MIP technology is the design of an artificial receptor with high selectivity for a specific analyte. Our approach combines N-isopropylacrylamide (NIPAM) backbone polymer with different functional monomers to improve the selectivity and sensitivity of 4-nitrophenol (4-NP) detection.The key points of our sensor polymer are:1) reduced amount of covalent crosslinker methylene bis-acrylamide (MBA) to increase rebinding kinetics and affinity and 2) modified polymer backbone with an electroactive block deposited on a gold surface. To get rapid high affinity template rebinding, we used a reduced amount of covalent crosslinker and used noncovalent crosslinking based on acid-base and hydrophobic interactions. To form acid-base crosslinking, we used 4-vinylpyridine (4-VP) as the basic monomer and methacrylic acid (MAA) as acidic monomer.In MIPs synthesis part, our strategy takes the advantage of reversible addition fragmentation-chain transfer (RAFT) polymerization to control the polymer chain length and modify the terminus as poly-ferrocene methyl methacrylate (FMMA), an electroactive block. The RAFT agent contains R group and Z group which are at different ends of polymer. The Z side is reduced to a thiol and deposited on gold. The PolyFMMA block is on the R side. RAFT agent, FMMA monomers and initiator were added to a batch system to synthesis the first electroactive block. Then, all chemicals including backbone monomers, functional monomers, crosslinkers and templates (4-NP) were added to form the major polymer block. After synthesis, templated-MIPs were dialyzed to remove the template for further target selective detection.One of the major challenges of our sensor is polymer tangling which affect measurement stability. To reduce polymer tangling effects, we dissolved the template-removed MIPs into tetrahydrofuran (THF) and controlled the gold electrode surface coverage. We deposited MIPs on an additional flat gold chip and used atomic force microscope (AFM) to characterize the surface coverage distribution.The modified gold electrode can be used in electrical impedance spectroscopy (EIS) or cyclic voltammetry (CV) to measure charge transfer distance before and after template rebinding to detect unknown concentration target analytes.

Molecular imprinted polymer based electrochemical sensor for selective detection of paraben

A new, simple, rapid, sensitive and selective disposable sensor platform was developed for the electrochemical detection of paraben based on molecular imprinting technique. Highly selective and specific recognition was established for the analyte through incorporating amino acid based polymerizable functional monomer. Paraben-imprinted poly-(2-hydroxyethyl methacrylate-N-methacryloyl-L-phenylalanine) (PHEMA-MAPA) nanofilm on a screen-printed gold electrode surface in the presence of polyvinyl alcohol (PVA) was synthesized by the molecular imprinting technique. Characterization of the fabricated electrode surfaces were performed with cyclic voltammetry (CV), atomic force microscopy (AFM) and attenuated total reflection fourier transform infrared spectrophotometry (ATR FT-IR). The electrochemical behavior of paraben was investigated using CV and electrochemical detection studies were carried out with square wave voltammetry (SWV). Under optimal conditions, the linear working range was found to be 1–30 μM with a low detection limit as 0.706 μM. The obtained recovery values proved that the developed sensor can be effectively applied to cosmetic samples. Besides, the fabricated disposable sensor system can be used successfully in the determination of other important analytes in the future due to its good sensor performance.

Nickel-Ferrite Oxide Decorated on Reduced Graphene Oxide, an Efficient and Selective Electrochemical Sensor for Detection of Furazolidone

Here, in this paper, magnetic nickel–ferrite oxide nanoparticles decorated reduced graphene oxide (NiFe2O4/rGO) was successfully prepared to employ as an efficient electrocatalyst for the electrochemical detection of furazolidone, an antibiotic and antibacterial drug. The NiFe2O4/rGO was characterized by different analytical methods, including FT–IR spectroscopy, X-ray diffraction spectroscopy, energy–dispersive X-ray spectroscopy, and electrochemical methods. In addition, the morphology of NiFe2O4/rGO was monitored using microscopic images of TEM and FE–SEM. NiFe2O4/rGO was used to modify a glassy carbon electrode (GCE). The differential pulse voltammetric studies represented that the NiFe2O4/rGO–GCE was more sensitive compared to rGO–GCE and unmodified GCE towards furazolidone detection. This electrochemical sensor was linearly related to furazolidone concentration in two linear ranges of 0.1– $10.0~\mu $ mol $L^{-1}$ and 10.0– $150.0~\mu $ mol $L^{-1}$ . However, the performance of this furazolidone sensor was quantitatively limited by the detection limit of $0.05~\mu $ mol $L^{-1}$ . To evaluate its selectivity, some common ions and other relevant species can interfere in the result of furazolidone sensor was investigated. This study, in addition to real sample analysis, represented that the suggested electrochemical sensor was practically selective and sensitive towards furazoldone. The determined value by the suggested sensor was in the related confidence interval accepted for the definite one.

Highly Sensitive and Selective Electrochemical Sensor for Detection of Escherichia coli by Using L-Cysteine Functionalized Iron Nanoparticles

The World Health Organization states that every year more than 3.4 million human deaths occur as a result of waterborne diseases. Here, we reported an innovative and amino functionalized electrochemical biosensor for the rapid detection of Escherichia coli (E. coli). Functionalized Fe3O4 NPs developed the sensor with L-cysteine, and cyclic voltammetry (CV) was employed to detect the bacteria. The results from this work are the first step toward the development of a portable water sensor that addresses the challenges of conventional time consuming and more expensive laboratory-based analyses. The detection of the targeted bacteria was performed with different bacteria to check the validity of the developed biosensor. Hence, the biosensor was highly selective to detect the E. coli from tap water samples. The signals current were increasing linearly while increasing the concentration of E. coli with the ranging from 101 to 105 CFU/mL with the linear correlation of (r2 = 0.879). The proposed electrochemical biosensor detects the E. coli in a lower concentration of 101 CFU/mL and with the maximum range of 105 CFU/mL. The results from this work demonstrate the first step in a portable biosensor for the routine monitoring of microbial contamination from water.

Molecularly Imprinted Polymer-Nanoporous Carbon Composite-Based Electrochemical Sensor for Selective Detection of Calycosin

In this study, a newfangled molecularly imprinted electrochemical sensor based on nanoporous carbon (NC) was constructed and applied to the sensitive determination of calycosin in complex Chinese medicine samples. Aniline as functional monomer and calycosin as template were used to assemble molecularly imprinted polymer (MIP), which was bonded to the surface of NC modified glassy carbon electrode (GCE) by electropolymerization. After characterization of the successfully prepared MIP/NC composite, the electrochemical performance of the proposed sensor (MIP/NC/GCE) was evaluated by cyclic voltammetry, electrochemical impedance spectroscopy and chronocoulometry. The results proved that the sensor could accelerate electron transfer rate and heighten specific surface area. Under optimized conditions, the proposed sensor was used to detect calycosin, which displayed good reproducibility, stability and selectivity. The method demonstrated a liner range of 4.20 × 10−7∼1.29 × 10−4 mol/L with the detection limit of 8.5 × 10−8 mol/L. Moreover, this study will provide a prospective exploration for the application of electrochemical analysis technology in the active ingredient detection of traditional Chinese medicine.

A Novel Biomass Derived Carbon Quantum Dots for Highly Sensitive and Selective Detection of Hydrazine

AbstractWe report for the first time, carbon quantum dots (CQD) based highly sensitive and selective electrochemical sensor for detection of hydrazine. CQD was synthesized by pyrolysis method using a natural precursor, chia seeds. The sensing ability was studied in terms of oxygen‐rich functional groups present on the surface of CQD.

Synthesis and characterization of nanostructure molecularly imprinted polyaniline/graphene oxide composite as highly selective electrochemical sensor for detection of p -nitrophenol

Abstract An electrochemical sensor for the determination of p-nitrophenol (p-NP) was developed based on a molecularly imprinted polymer (MIP) on graphene oxide (GO). The sensor was prepared via precipitation polymerization of aniline and ammonium persulfate as the host molecule and initiator. The morphologies and electrochemical behavior of the imprinted sensor were characterized by Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), field emission electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS) and cyclic voltammetry techniques. The electrochemical investigations were conducted by screening the effects of pH, p-NP concentration and scan rate. Under the optimized experimental conditions, the oxidation peak current varies linearly with p-NP concentration, in the range 6 × 10−5–14 × 10−5 mol/L with a detection limits of 2 × 10−5 mol/L (correlation coefficient of 0.991). The electrochemical sensor was also used to detect p-NP in tap water, where it shows the excellent recoveries. Moreover, the sensor probe revealed an excellent selectivity for p-NP compared to other phenol derivatives. This proposed sensor was used successfully for determination of spiked p-nitrophenol in water samples.

Highly sensitive and selective electrochemical sensor for detection of vitamin B12 using an Au/PPy/FMNPs@TD-modified electrode

A new electrochemical sensor for sensitive and selective detection of vitamin B12 (VB12) was constructed by the electropolymerization of pyrrole (Py) in the presence of ferromagnetic nanoparticle-incorporated triazine dendrimer (FMNPs@TD) on a gold electrode (Au). The gold/polypyrrole/ferromagnetic nanoparticles/triazine dendrimer (Au/PPy/FMNPs@TD) electrode showed electrocatalytic activity for the reduction of VB12 in Britton-Robinson buffers. The performance and interaction of the Au/PPy/FMNPs@TD with VB12 were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), differential pulse voltammetric (DPV), UV–vis spectroelectrochemistry, and density functional theory calculations. The resulting sensor exhibited excellent performance for determination of VB12 with a wide linear range (2.50 nM–0.5 μM), highly reproducible response (RSD of 2.3%), low percentage of interferences, and long-term stability. The limit of detection (LOD) and limit of quantitation (LOQ) values for the determination of VB12 were 0.91 and 3.00 nM, respectively. The electron transfer rate constants (ks), charge transfer coefficient (α), surface concentrations of electroactive species (Г), and disproportionation equilibrium constant (KD) for Au/PPy/FMNPs@TD-modified electrodes were calculated. Finally, the constructed sensor was applied to the determination of VB12 in food samples.