Electrochemical Sensor For Sensitive Detection Research Articles

A facile fabrication of ratiometric electrochemical sensor for sensitive detection of riboflavin based on hierarchical porous biochar derived from KOH-activated Soulangeana sepals

Herein, a facile ratiometric electrochemical method was developed for sensitive sensing of riboflavin (RF) based on hierarchical porous biochar (HPB) modified electrode. In this sensing system, the reference paracetamol (PA) was directly added into electrolyte solution without the requirement of complex immobilization process. HPB derived from KOH-activated Soulangeana sepals displays hierarchical porous structure, high specific surface area and rich oxygen-containing functional groups, which is favorable for RF adsorption and enrichment. Besides, the excellent electronic conductivity and superior electrocatalytic activity of HPB can effectively promote the electrooxidation of RF. Moreover, the dual-signal strategy greatly improves the reproducibility and reliability of electrochemical detection. Based on the proposed ratiometric sensing platform, the sensor exhibits a wider linear range of 0.0007–10 μM and a lower limit of detection of 0.2 nM. The method also presents good selectivity and has been applied to the determination of RF in milk samples with satisfactory results.

Monoclinic WO3 nanosheets-carbon nanotubes nanocomposite based electrochemical sensor for sensitive detection of bisphenol A

• WO 3 -CNT nanocomposite was hydrothermally prepared and used as a novel sensing material. • WO 3 -CNT/GCE has enhanced electro-oxidation peak current and reduced potential for BPA. • Improved surface area, good electron transfer and reproducibility of the sensor. • WO 3 -CNT/GCE sensor for BPA has two linear ranges with low detection limit (16.3 nM) • Admirable performance of the sensor for the practical applicability in real samples. A novel and sensitive electrochemical sensor based on monoclinic tungsten trioxide (WO 3 ) nanosheets-carbon nanotubes nanocomposite (WO 3 -CNT) modified glass carbon electrode (GCE) is developed for the direct detection of endocrine disruptor bisphenol A (BPA) in textile sample for the first time. The electrochemical behavior of BPA on the resultant WO 3 -CNT/GCE sensor is investigated using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and chronocoulometry (CC). Under the optimized conditions, the proposed sensor can be adopted to the quantification of BPA using differential pulse voltammetry (DPV), and the electro-oxidation peak current is proportional to the BPA concentration in the range of 0.03–3.0 μM and 3.0–100 μM with a correlation coefficient of 0.9993 and 0.9992, respectively. Moreover, the proposed sensor with a detection limit of 16.3 nM (S/N = 3) exhibits good reproducibility, selectivity and stability, and can be successfully applied to detect the BPA concentrations in real samples (textile, plastic and tap water) with satisfactory recovery (99.4%-110.1%). The present strategy on the hybridization of CNTs and WO 3 enables more opportunities for the electrochemical detection of BPA in the practical applications.

Construction of La2O3-CeO2 Composites Modified Glassy Carbon Electrode as a Novel Electrochemical Sensor for Sensitive Detection of Nitrite

Abstract An electrochemical sensor for the determination of nitrite based on La2O3-CeO2 composite modified glassy carbon electrode (La2O3-CeO2/GCE) was fabricated in this study. La2O3-CeO2 composites were prepared by reflux condensation, and their morphology and structure were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The electrochemical behavior of nitrite on the modified electrode was investigated by cyclic voltammetry (CV) and an irreversible oxidation peak emerged at 0.7 V (pH = 7). The effects of scan rate and pH on electron transfer efficiency of fabricated electrode were investigated by CV. Under the optimum conditions, the modified electrode performed outstanding electrocatalytic activity for nitrite detection with a linear range of 0.25–4000 µM and a low detection limit of 0.015 µM (S/N = 3). The constructed sensor was successfully used for the determination of nitrite in real water samples with satisfactory results (recoveries between 94.0% and 106.6%). It provides a foundation and reference for the determination of nitrite in various environmental samples.

Preparation of highly sensitive electrochemical sensor for detection of nitrite in drinking water samples

Nitrite is both an environmental contaminant and a food additive. Excessive intake of nitrites not only causes blood diseases, but also has the potential risk of causing cancer. Therefore, rapid detection of nitrite in water is necessary. In this work, we propose an electrochemical sensor for the sensing of nitrite. Glassy carbon electrodes modified with noble metal nanomaterials have been widely used in the preparation of sensors, but the surface properties of noble metals largely affect the sensing performance. This work proposes the biosynthesis of Au nanoparticles using the pollen extract of Lycoris radiata as a reducing agent. Flavonoids rich in pollen can be used as weak reducing agents for the reduction of chloroauric acid, and slowly synthesize uniformly dispersed Au nanoparticles. These Au nanoparticles do not agglomerate because they contain small biological molecules on the surface and can form a homogeneous sensing interface on the electrode surface. The electrochemical sensor assembled with biosynthesized Au nanoparticles provides linear detection of nitrite between 0.01 and 3.8 mM. The sensor also has excellent immunity to interference. In addition, the proposed sensor was also successfully used for the detection of nitrite in drinking water.

Thiamine-functionalized silver–copper bimetallic nanoparticles-based electrochemical sensor for sensitive detection of anti-inflammatory drug 4-aminoantipyrine

Thiamine-functionalized silver–copper bimetallic nanoparticles-based electrochemical sensor for sensitive detection of anti-inflammatory drug 4-aminoantipyrine

A high-performance electrochemical sensor for sensitive detection of tetracycline based on a Zr-UiO-66/MWCNTs/AuNPs composite electrode.

Herein, a high-performance electrochemical sensor was constructed based on a metal-organic framework (Zr-UiO-66)/multi-carbon nanotubes/gold nanoparticles (Zr-UiO-66/MWCNTs/AuNPs) composite modified glassy carbon electrode for sensitive determination of tetracycline. The morphology, structure, and performance of Zr-UiO-66/MWCNTs/AuNPs were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), and electrochemical techniques. The Zr-UiO-66/MWCNTs/AuNPs nanohybrids exhibited excellent electrocatalytic activity towards the oxidation of tetracycline, mainly because of the synergistic effect of the MOFs, MWCNTs, and gold nanoparticles. The electrochemical kinetics and catalytical mechanism of tetracycline were demonstrated, proving that tetracycline's electrocatalytic oxidation reaction was an absorption-controlled two-step process involving the transfer of two protons and two electrons, respectively. Furthermore, a simple and facile method was used to achieve the regeneration of the absorbed saturated electrode. A low concentration of tetracycline was detected by amperometry with the linear ranges of 5 × 10-7 to 2.25 × 10-4 mol L-1 (R2 = 0.9941), the sensitivity was 45.4 mA L mol-1, and the limit of detection was as low as 1.67 × 10-7 mol L-1 (S/N = 3). In addition, the composite electrode demonstrated high selectivity (interference deviation of ± 5%), satisfactory reproductivity (RSD of 5.31%), and long-term stability (easy regeneration) and was successfully applied in the analysis of tetracycline antibiotics in actual samples. Thus, the proposed electrode provides a promising and prospective MOFs-based sensing platform for the detection of tetracyclines in the environment.

Sensitive electrochemical sensor based on nickel/PDDA/reduced graphene oxide modified screen-printed carbon electrode for nitrite detection.

A simple, rapid method of the determination of nitrite in food samples is reported by using a highly sensitive electrochemical sensor based on nickel, poly(diallyldimethylammonium chloride) (PDDA), reduced graphene oxide (rGO) and a disposable screen-printed carbon electrode (SPCE). The method is based on a modification of the electrode to enhance the sensitivity and selectivity of the disposable and applicable SPCE, which is essential for the present analytical challenge. The nitrite determination was performed by using a cyclic voltammetry (CV) method under optimum conditions. Ni/PDDA/rGO/SPCE showed a linear working range of 6 to 100 μM of nitrite concentration. The limit of detection and limit of quantification were 1.99 μM (S/N = 3) and 6.6 μM (S/N = 10), respectively. The sensitivities were 0.453 μA μM-1 cm-2 for the lower concentration range and 0.171 μA μM-1 cm-2 for the higher concentration range. The Ni/PDDA/rGO sensor also showed excellent anti-interference ability and good long-term stability. The purposed disposable sensor was successfully applied to determine nitrite in sausages and pickled vegetable samples with satisfactory recovery.

β-Cyclodextrin-functionalized graphene and metal-organic framework composites for ultrasensitive electrochemical detection of chloramphenicol.

Novel β-cyclodextrin (β-CD)@functionalized graphene (G)/Cu-1,3,5-benzenetricarboxylic acid (BTC) composites were in situ prepared using β-CD functionalized graphene and Cu-BTC, and a new electrochemical sensor for sensitive detection of chloramphenicol (CAP) was developed based on the composites. A series of investigations on the β-CD@G/Cu-BTC composite material were conducted. The β-CD functionalized graphene solution has an excellent and stable dispersion effect. The composite was further combined with metal-organic frameworks (MOFs) to overcome the disadvantages of a single material, displaying excellent conductivity and a synergistic catalytic effect on the detection of chloramphenicol; so an electrochemical sensor for CAP detection is developed. An actual sample was also detected using the proposed sensor.

An electrochemical sensor for sensitive detection of dopamine based on a COF/Pt/MWCNT–COOH nanocomposite

A novel COF-based nanocomposite COF/Pt/MWCNT–COOH with excellent electrocatalytic activity was synthesized through a simple solution method and applied to an electrochemical biosensor.

Detection of pesticide using Cu-rGO modified electrochemical sensor

The increased population of the world has intensified the demand for food, which escalates the use of pesticides in agricultural fields. The pesticides contaminate food, soil, and water bodies. The present article focuses on the detection of pesticides in runoff water from agricultural fields. In this study, a high sensitive electrochemical sensor for detection of organophosphate with the help of Cu-rGO nanocomposite. Cu-rGo was synthesized using the co-precipitation method and GO was synthesized using modified hummer’s method. The scanning Electron microscope, X-ray diffraction, and Raman spectroscopy confirmed the successful synthesis of the nanocomposite. The surface morphology of the nanocomposite was obtained from SEM analysis. Cyclic voltammetry and differential pulse voltammetry was performed using corrtest Potentiostat (CS 350) and a three-electrode setup for determination of electrochemical behavior of Cu-rGO nanocomposite and its interaction with malathion. Cu-rGO nanoparticles were deposited on the surface of a glassy carbon electrode and used as a working electrode and Ag/AgCl electrode as reference electrode and platinum wire as the counter electrode was used for detection of pesticide. Altogether, Cu-rGO modified electrode produced a very good result for the determination of pesticide in runoff water samples of agricultural fields.

Highly sensitive determination of benorilate using silver nanoparticles/polyindole/reduced graphene oxide nanocomposite modified electrode

It is known that excessive intake of drugs can cause harmful side effects to the human body. Monitoring of drugs in tablets is important to control levels below allowable limits. Herein a novel electrochemical sensor for sensitive detection of benorilate was developed using silver nanoparticles-polyindole-reduced graphene oxide (AgNPs-PIn-rGO) nanocomposite. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to investigate the electrochemical behavior of benorilate. The AgNPs-PIn-rGO nanocomposite exhibited outstanding electrocatalytic activity toward benorilate. In addition, the effects of scaning rate, pH and accumulation time on the performance of the electrochemical sensor were also studied. Under the optimal condition, the designed sensor showed an appreciable linear response range (0.06 μM-80 μM) and a low detection limit (6 nM). Meanwhile, the sensor also displayed excellent selectivity and good storage stability. More importantly, the established method was successfully applied for benorilate determination in pharmaceutical tablets and the result was satisfactory.

Au@Carbon quantum Dots-MXene nanocomposite as an electrochemical sensor for sensitive detection of nitrite

A highly sensitive electrochemical sensor was developed through a one-pot green synthesis method for nitrite detection based on the electrochemical technique. Xylan-based carbon quantum dots (CQDs) were used as green in situ reducing agent to prepare CQDs capped gold nanoparticles (Au@CQDs). MXene of good electrical conductivity was used as the immobilized matrix to fabricate Au@CQDs-MXene nanocomposites with the advantages of good electrical conductivity and electrocatalysis. An electrochemical sensor for nitrite monitor was obtained by loading the Au@CQDs-MXene on a glassy carbon electrode. The sensor presents high sensitivity, good stability, wide linear range, and excellent selectivity due to the high catalytic activity of AuNPs and CQDs, the large specific surface area of MXene, and exceptional electrical conductivity of AuNPs and MXene. Under the optimal condition, the linear detection range of the sensor was from 1 μM to 3200 μM with a detection limit of 0.078 μM (S/N = 3), which was superior to most reported sensors using differential pulse voltammetry (DPV) method. Furthermore, this sensor was successfully applied to detect nitrite in tap water and salted vegetables with satisfactory recoveries. This modified electrocatalytic sensor shows a new pathway to fabricate nitrite detection sensor with feasibility for practical application.

Nickle-ion-substituted ceria nanoparticles-based electrochemical sensor for sensitive detection of thiourea

Nickle-ion-substituted ceria nanoparticles-based electrochemical sensor for sensitive detection of thiourea

A simple label-free electrochemical sensor for sensitive detection of alpha-fetoprotein based on specific aptamer immobilized platinum nanoparticles/carboxylated-graphene oxide

A label-free electrochemical aptamer-based sensor has been fabricated for alpha-fetoprotein (AFP) detection. Platinum nanoparticles on carboxylated-graphene oxide (PtNPs/GO-COOH) modified screen-printed graphene-carbon paste electrode (SPGE) was utilized as an immobilization platform, and the AFP aptamer was employed as a bio-recognition element. The synthesized GO-COOH helps to increase the surface area and amounts of the immobilized aptamer. Subsequently, PtNPs are decorated on GO-COOH to enhance electrical conductivity and an oxidation current of the hydroquinone electrochemical probe. The aptamer selectively interacts with AFP, causing a decrease in the peak current of the hydroquinone because the binding biomolecules on the electrode surface hinder the electron transfer of the redox probe. Effects of aptamer concentration and AFP incubation time were studied, and the current changes of the redox probe before and after AFP binding were investigated by square wave voltammetry. The developed aptasensor provides a linear range from 3.0–30 ng mL−1 with a detection limit of 1.22 ng mL−1. Moreover, the aptamer immobilized electrode offers high selectivity to AFP molecules, good stability, and sensitive determination of AFP in human serum samples with high recoveries.

DNA Triple Helix Complex-Functionalized Electrochemical Sensor for Sensitive Detection of MicroRNA in Human Serum

The selective and sensitive monitoring of microRNAs (miRNAs) plays essential roles in cancer diagnosis. Herein, on the basis of DNA triple helix and toehold-mediated strand displacement reaction (TSDR), the construction of a simple electrochemical sensing system is reported for monitoring of let 7a in human serum. The triple helix complex probe (THCP) consisting of signal probe (MB-SP) labeled with methylene blue (MB) and capture probe (CP) is first assembled onto the sensing interface. The presence of target let 7a initiates the disassembly of THCP structure and conformational change of MB-SP. And the hairpin probe (HP) triggers the TSDR amplification and achieves the recycling of target let 7a, thus leading to massive MB-SP turning into molecular beacon structure, which causes the significantly amplified MB signal for monitoring of let 7a down to femtomolar level. In addition, taking advantage of TSDR signal amplification and the high selectivity of the THCP, the selective discrimination of let 7 miRNAs family members and circulating miRNAs detection in human serum are accomplished, which would supply a simple and sensitive monitoring approach for early clinical diagnostics.

Electrodeposited copper bismuth oxide as a low-cost, non-enzymatic electrochemical sensor for sensitive detection of uric acid and hydrogen peroxide

We report for the first-time copper bismuth oxide (CuBi2O4) as an electrochemical sensor for the oxidation of uric acid and reduction of hydrogen peroxide. CuBi2O4 films are prepared on FTO via electrodeposition and used as a working electrode. Structural and morphological studies of CuBi2O4 were done by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), X-ray photoelectron microscopy, tunneling electron microscopy (TEM). Electrochemical studies were performed using cyclic voltammetry (CV), chronoamperometry with CuBi2O4 electrode for the detection of uric acid (UA) and hydrogen peroxide (HP). High sensitivities of 206.7 and 280.6 μA mΜ-1 cm−2 were achieved for the detection of UA and HP. Therefore, CuBi2O4 can be a potential candidate to explore for sensing applications.

A Nanometer-Sized Graphite/Boron-Doped Diamond Electrochemical Sensor for Sensitive Detection of Acetaminophen.

A boron-doped diamond (BDD) has been widely used as an outstanding electrode for constructing high-performance electrochemical biosensors. In this paper, we fabricated a novel electrode combined of nanometer-sized graphite-BDD film (NG-BDD) by chemical vapor deposition. The nanometer-sized graphite (NG) is formed on the (111) facet of BDD via converting an sp3 diamond structure to an sp2 graphitic phase at high temperature in boron-rich ambient. The electrode was characterized by means of scanning electron microscopy, Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. This NG-BDD was performed as an electrode of electrochemical biosensor to detect trace acetaminophen (APAP) accurately. Cyclic voltammetry and differential normal pulse voltammetry are used to investigate the overall performance of the electrochemical device. The sensor has a linear electrochemical response to APAP in the concentration range of 0.02–50 μM, and the detection limit is estimated to be as low as 5 nM. The research has resulted in a solution of constructing a reusable NG-BDD sensor to detect APAP with stability and show potential in extensive application.

A facile, inexpensive and green electrochemical sensor for sensitive detection of imidacloprid residue in rice using activated electrodes.

The development of sensitive, facile, cost-effective and eco-friendly sensors is essential for monitoring imidacloprid (IDP) residue on a large scale. Compared with popular modification of electrodes with advanced materials, electrochemical activation is promising at this point. In this paper, we found that strongly basic electrolytes (e.g. KOH and K3PO4) and applying cyclic potential during the activating process are beneficial to greatly amplify the electro-reduction response of IDP by nearly 16 times. Combining the characterization of activated electrodes with electrochemical behavior analysis of IDP, it is speculated that specific oxygen-contained functional groups were formed to bond with IDP molecules, leading to fast electron transfer kinetics. Then a sensitive IDP sensor has been developed with a low limit of detection (LOD) of 0.03 μM in the range of 0.1-100 μM. The methodological evaluation including reproducibility, stability and recovery has been also carefully studied, verifying the potential of proposed activated electrodes for application in rice samples.

MXene improves the stability and electrochemical performance of electropolymerized PEDOT films

Poly(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(styrene sulfonate) (PSS) is the most commonly used conducting polymer in organic bioelectronics. However, electrochemical capacitances exceeding the current state-of-the-art are required for enhanced transduction and stimulation of biological signals. The long-term stability of conducting polymer films during device operation and storage in aqueous environments remains a challenge for routine applications. In this work, we electrochemically synthesize a PEDOT composite comprising the water dispersible two-dimensional conducting material Ti3C2 MXene. We find that incorporating MXene as a co-dopant along with PSS leads to PEDOT:PSS:MXene films with remarkably high volumetric capacitance (607.0 ± 85.3 F cm−3) and stability (capacity retention = 78.44% ± 1.75% over 500 cycles), outperforming single dopant-comprising PEDOT films, i.e., PEDOT:PSS and PEDOT:MXene electropolymerized under the same conditions on identical surfaces. The stability of microfabricated PEDOT:PSS:MXene electrodes is evaluated under different conditions, i.e., when the films are exposed to sonication (∼100% retention over 6 min), upon immersion in cell culture media for 14 days (∆|Z| = 2.13%), as well as after continuous electrical stimulation. Furthermore, we demonstrate the use of a PEDOT:PSS:MXene electrode as an electrochemical sensor for sensitive detection of dopamine (DA). The sensor exhibited an enhanced electrocatalytic activity toward DA in a linear range from 1 µM to 100 μM validated in mixtures containing common interferents such as ascorbic acid and uric acid. PEDOT:PSS:MXene composite is easily formed on conductive substrates with various geometries and can serve as a high performance conducting interface for chronic biochemical sensing or stimulation applications.

Gold nanoparticles based electrochemical sensor for sensitive detection of uranyl in natural water

To precisely determine uranium in aqueous solution, we combined the synthesis of gold nanoparticles (AuNPs) with stripping voltammetry to develop a new electrochemical detection method with high sensitivity toward uranyl ions on account of its enrichment by deposition and determination by stripping. The uranyl was reduced and deposited on the surface of the electrode followed up with a stripping process catalyzed by AuNPs to determine the concentration of uranyl ions. The experimental parameters, such as pH, deposition potential and time were optimized. Under optimal conditions, the stripping voltammetry response of the modified electrode to uranyl shows a linear relationship with the concentration from 2.4 μg L −1 to 48 μg L −1 and 48 μg L −1 to 480 μg L −1 , respectively. The AuNPs based electrode could be used to determine the concentration of uranyl ion in a few minutes with a detection limit of 0.3 μg L −1 . The reproducibility and reliability of the electrode were also evaluated with good results. Finally, the proposed procedure was successfully applied to the determination of uranyl ions in natural water. This method is potentially applicable for the on-site environmental analysis. • A detection of limit down to 0.3 μg L −1 was obtained by anodic stripping voltammetry. • The developed electrochemical method exhibited wide dynamic range from 2.4 μg L −1 to 480 μg L −1 . • Method gives accurate results in natural waters.