Construction Of Electrochemical Sensor Research Articles

Selective and simultaneous sensing of ascorbic acid, dopamine and uric acid based on nitrogen-doped mesoporous carbon.

Development of novel sensing nanostructures for facile, economical and fast applications has attracted more and more interest. Herein, a nitrogen-doped mesoporous carbon (NMC) was synthesized by pyrolyzing a mixture of melamine and carbon black at a low-temperature (600 °C) and exploited for the simultaneous sensing of ascorbic acid (AA), dopamine (DA) and uric acid (UA). The as-made NMC exhibits a rougher surface and smaller size than carbon black. Such a one-pot method is very versatile, quick and inexpensive, easy to handle (solvent-, catalyst-, and template-free) and scalable. The oxidation potentials of the NMC/GCE negatively shift and the current responses are enhanced greatly towards the oxidation of AA, DA and UA thanks to the large surface area, mesoporous structure and N-doped active sites. The peak to peak potential separations are 258 and 410 mV for AA-DA and AA-UA. The linear ranges of AA, DA and UA are 5-4500 μM, 0.005-35 μM and 0.5-3500 μM, respectively, and their detection limits are 0.15 μM (AA), 1.6 nM (DA) and 0.15 μM (UA). Meanwhile, the NMC/GCE exhibits satisfactory stability and anti-interference ability. These results show that NMC could be a promising candidate material for electrochemical sensor construction.

Bimetal-organic framework Cu-Ni-BTC and its derivative CuO@NiO: Construction of three environmental small-molecule electrochemical sensors

The bimetal-organic framework Cu-Ni-BTC (1,3,5-Benzenetricarboxylic acid, H3BTC) and its derivative CuO@NiO were used as the basis of the construction of electrochemical sensors for three environmental small-molecules. Firstly, the Cu-Ni-BTC-CPE modified electrode was investigated by electrochemical measurement, the results showed that linear responses of the proposed sensor ranged from 0.5 μM to 330 μM for catechol (CT) and 0.3 μM to 390 μM for hydroquinone (HQ), with detection limits of 0.2 μM and 0.08 μM, respectively. Secondly, CuO@NiO was prepared by calcination, and myoglobin (Mb) was subsequently immobilized on a sensing interface based on CuO@NiO and ionic liquid (IL) composite membrane where IL possessed good electrical conductivity, wide electrochemical potential window, excellent film forming as well as good biocompatibility. Spectroscopic and electrochemical examinations revealed that Mb remained its bioactivity on the surface of CuO@NiO/IL composite film, and had excellent electrocatalytic activity towards nitrite (NO2−) in ranges of 1.0–1536 μM and 1536–3636 μM, and the detection limit was low to 0.4 μM, the apparent Michaelis-Menten constant (KM) was 0.42 mM. The results showed that MOFs and its derivative have different catalytic performance. The biggish difference in catalyst activity and selectivity provides a new idea and theoretical guidance for the further studies on electrochemical sensors.

The use of CeO2-modified Pt/C catalyst inks for the construction of high-performance enzyme-free H2O2 sensors

In this work, the development of novel enzyme-free electrochemical hydrogen peroxide (H2O2) sensors with high sensitivity and wide linear range is described. The electrochemical sensors were constructed by the physical modification of commercial Pt/C catalysts with CeO2 metal oxide nanoparticles. X-ray diffraction (XRD), transmission electron microscopy (TEM), N2-adsorption, and Raman spectroscopy methods were used to characterize the metal oxide nanoparticles. The CeO2 particles showed fluorite-type structure with the average crystalline size of 13.8nm. Furthermore, the Raman spectroscopy results indicated the presence of high degree of oxygen defects indicating the high redox property of the nanoparticles. The physical surface area of the metal oxide nanoparticles was determined to be 68.8m2g−1. The catalyst inks were prepared by mixing commercial Pt/C and CeO2 nanoparticles with different weight ratios. The analytical performance of the sensors was studied using cyclic voltammetry (CV) and chronoamperometry (CA) methods. The results revealed that the introduction of CeO2 nanoparticles into the catalyst layer improved the sensor performance significantly compared to Pt/C sensors. A high sensitivity of 185.4±6.5μAmM−1cm−2 was obtained from CeO2-modified sensors in a wide linear range of 0.01–30mM. Depending on the obtained results it can be suggested that the novel sensor design holds a great promise for the construction of electrochemical sensors with high sensitivity, selectivity, and wide working window.

Electrochemical study of hydrazine oxidation by leaf-shaped copper oxide loaded on highly ordered mesoporous carbon composite

Hydrazine is a possible human carcinogen because of its hyper toxicity. Therefore, the determination of hydrazine is particularly important for environmental protection and public security. Electrochemical method for the detection of hydrazine has drawn great interests because of its high sensitivity, fast response time, simple operation, and low cost. In this work, a leaf-like copper oxide (CuO) anchored onto wormlike ordered mesoporous carbon (OMC) composite was prepared for the construction of an electrochemical sensing platform for hydrazine. Because of the synergetic catalytic effect and unique structural properties, the obtained nanosized CuO incorporated in OMC exhibited good electrocatalytic performance for the oxidation of hydrazine with a catalytic rate constant (kcat) of 1.28 × 105 M−1s−1. Moreover, the content ratio of CuO: OMC was optimized to improve the electrocatalytic performance. The CuO/OMC hybrids can act as a sensitive and effective sensing platform for the determination of hydrazine, exhibiting wide linear range, high sensitivity, low limit of detection, and good stability. This comprehensive and systematic study may provide great opportunities for the design and construction of electrochemical sensors for environmental monitoring.

ZnO nanostructure-based electrochemical biosensor for Trichinella DNA detection

A DNA electrochemical sensor's construction based on ZnO nanostructured electrodes is described in the article. As object of the study, DNA primers and PCR products of Trichinella britovi and Trichinella spiralis were chosen. The sensors were prepared with different morphologies of ZnO structures on the surfaces of the working electrodes: thin film of zinc oxide, nanorods and nanotubes. Immobilization processes of DNA primers were studied. Differential Pulse Voltammetry was used as a method of measurements of electrochemical characteristics. The measurements have shown an eligible difference of signals for confident distinction of Trichinella britovi and Trichinella spiralis PCR products.

Enhanced electrochemical sensitivity towards plasticizer determination based on ferrocene- end-cap dendrimer functionalized graphene oxide electrochemical sensor

We fabricated a novel sensitive ferrocene end-cap polyester dendrimer (Fc-PED)- graphene oxide (GO) modified glassy carbon electrode (Fc-PED/GO/GCE) for direct quantification of Di(2-methoxyethyl) phthalate (DMEP) in liquor sample. GO sheets were bonded on the Fc-PED molecules by the chemical reaction between Fc-PED and GO sheets to form Fc-PED-GO composites. Construction of electrochemical sensors using the structure of nano-sized dendrimer will offer compact matrix for the incorporation of GO sheets, which provided more possibilities for the design of sensor to improve the film forming performance and the electrochemical activity of the electrode. GO sheet also provided a larger surface area to facilitate deposition of Fc-PED redox probe, which increased the current response of the modified sensor. The Fc-PED/GO/GCE sensor demonstrated a wide linear detection range of 0.06-1200 μmol.L−1with a low detection limit of 0.04μmol.L−1. Furthermore, the sensor showed higher sensitivity, good selectivity and reproducibility towards DMEP detection. The feasibility of the electrochemical sensor was proved by successful detection of DMEP in real liquor samples. Possible synergistic effect of Fc-PED and GO towards DMEP detection are proposed based on experimental results.

The synergistic effect of Au-COF nanosheets and artificial peroxidase Au@ZIF-8(NiPd) rhombic dodecahedra for signal amplification for biomarker detection

Here, a new type of signal amplification strategy is proposed employing Au nanoparticle (AuNP)-functionalized covalent organic framework (Au-COF) nanosheets and AuNP functionalized ZIF-8(NiPd) (Au@ZIF-8(NiPd)) rhombic dodecahedra nanocomposites for sandwich electrochemical sensor construction. The peroxidase mimics Au@ZIF-8(NiPd) took the place of natural enzymes in enzyme-assisted amplification strategies, both acting as catalysts for H2O2 reduction for signal amplification, and serving as ideal nanocarriers for signal probe anchoring. The cancer biomarker thrombin (TB) was selected as the target. Thrombin binding aptamers (TBA 2) were fixed on Au@ZIF-8(NiPd), and the obtained TBA 2-Au@ZIF-8(NiPd) bioconjugates were employed as tracer labels, and TB was sandwiched between the tracer labels and capture probe TBA 1 which were immobilized on the Au-COF nanosheet modified electrode. Au-COFs with a high specific area, super electroconductivity, and uniformly distributed AuNPs were utilized as the electrode substrate to fix TBA 1. Exploiting the sandwich method, the proposed TB aptasensor exhibited a wide linear range of 0.1 pM to 20 nM with a low detection limit of 15 fM (S/N = 3). The ingenious sensing strategy enriched the application diversity of the artificial enzyme and showed promise in research and development of point-of-care diagnostics.

New Generation of Electrochemical Sensors Based on Multi-Walled Carbon Nanotubes

Multi-walled carbon nanotubes (MWCNT) have provided unprecedented advances in the design of electrochemical sensors. They are composed by sp2 carbon units oriented as multiple concentric tubes of rolled-up graphene, and present remarkable active surface area, chemical inertness, high strength, and low charge-transfer resistance in both aqueous and non-aqueous solutions. MWCNT are very versatile and have been boosting the development of a new generation of electrochemical sensors with application in medicine, pharmacology, food industry, forensic chemistry, and environmental fields. This work highlights the most important synthesis methods and relevant electrochemical properties of MWCNT for the construction of electrochemical sensors, and the numerous configurations and successful applications of these devices. Thousands of studies have been attesting to the exceptional electroanalytical performance of these devices, but there are still questions in MWCNT electrochemistry that deserve more investigation, aiming to provide new outlooks and advances in this field. Additionally, MWCNT-based sensors should be further explored for real industrial applications including for on-line quality control.

Preparation of highly conductive biochar nanoparticles for rapid and sensitive detection of 17β-estradiol in water

We developed a sensitive and cost effective sensor based on highly conductive and adsorptive biochar nanoparticles for electrochemical detection of 17β-estradiol. The biochar is ubiquitous and has the advantages of large specific surface area, cost effectiveness, and good stability, which has the potential to be utilized for electrode construction as long as the conductivities are guaranteed. We obtained nano sized biochar particles (BCNPs) and investigated electrochemical properties of the BCNPs with variation of the pyrolysis conditions. BCNPs with high conductivity (BCNP800) were obtained and utilized for reproducible and stable electrochemical sensor construction. The produced highly conductive BCNP800 sensor had exhibited improved amperometric responses such as decreased impedance, lowered anodic potential and enhanced current signal toward 17β-estradiol compared with the pristine glassy carbon electrode. In addition, the adsorption-accumulation by BCNP800 for 17β-estradiol resulted in great sensing signal amplification. With synergetic effect of high adsorption and conductivity properties of the BCNP800 sensor a detection limit of 11.30 nM was obtained. The accuracy and reliability of the BCNP800 sensor were confirmed to be compatible with the high performance liquid chromatography analysis and it could be successfully applied for real environmental water analysis.

Ferrocene-terminated dendrimer functionalized graphene oxide layered sensor toward highly sensitive evaluation of Di(2-ethylhexyl) phthalate in liquor samples

We demonstrate the use of a dendrimer functionalized graphene oxide (GO) to fabricate a novel sensitive ferrocene-terminated poly(amine) ester dendrimer (Fc-AED)-GO modified glassy carbon electrodes (Fc-AED/GO/GCE) for direct quantification of Di(2-ethylhexyl) phthalate (DEHP) in liquor sample. GO sheets were grafted on the Fc-AED molecules by the esterification reaction between carboxylic end group in Fc-AED and hydroxyl group on GO sheets so as to form Fc-AED-GO composites. Construction of electrochemical sensors using the structure of nanosized dendrimer can provide compact matrix for the incorporation of GO to improve the adhesion of GO on electrode, which would be more possible for the design of sensor to improve the film forming performance and then increase the electrochemical activity of the electrode. Additionally, it can directly use the redox probe of ferrcene to sense the content variation of analyte. The GO also provides a larger surface area to facilitate deposition of Fc-AED redox probe resulting in the increased current response of the modified sensor. The modified sensor exhibites a wide linear response to DEHP and a low detection limit of 0.06 μM with higher sensitivity, good selectivity, and a better reproducibility promising to be a useful tool in the DEHP evaluation. The outstanding performance of the developed sensor could be attributed to the synergistic effect of Fc-AED and GO. Possible redox mechanism of DEHP on Fc-AED/GO/GCE are proposed based on experimental results.

Simultaneous electrochemical sensing of hydroquinone and catechol using nanocomposite based on palygorskite and nitrogen doped graphene

Abstract A novel electrochemical sensor based on nitrogen doped graphene (NGE) and palygorskite (Pal) for the simultaneous detection of hydroquinone (HQ) and catechol (CT) has been proposed. Pal is particularly pointed out for its appreciable specific surface area and reactive-OH groups on its surface. Acid treatment Pal demonstrated better physico-chemical properties, which are propitious to electrochemical sensor construction. The introduction of NGE not only improved the poor conductivity of Pal but also served as an excellent adherent matrix. The modified electrode demonstrated the enhanced redox peak currents of HQ and CT with good discrimination. Under optimized conditions, the linear ranges for HQ and CT were 2–50 μM and 1–50 μM, with detection limit (LOD) of 0.8 μM and 0.13 μM, respectively. The result designates that the Pal/NGE composite promises to be a new eco-friendly modified material for sensor fabrication.

Electrochemical sensor construction based on Nafion/calcium lignosulphonate functionalized porous graphene nanocomposite and its application for simultaneous detection of trace Pb2+ and Cd2+

Here, a new porous graphene (PGR) based nanocomposite was synthesized by a chemical and thermal reduction of graphite oxide in the assistance of calcium lignosulfonate (CLS), and characterized by scanning electron microscopy SEM, TEM, XPS, Zeta potential analysis, FTIR and EIS. Then the as-prepared CLS/PGR was used along with Nafion to modify a glassy carbon electrode (GCE) for constructing electrochemical sensor to detect Pb2+ and Cd2+ simultaneously. Compared with the bare GCE, the reduced graphene oxide/GCE, and the CLS/PGR/GCE, the Nafion/CLS/PGR/GCE exhibited improved electrochemical performance in detecting the two ions. It could be ascribed to the synergistic contribution from PGR, CLS and Nafion, which integrated the advantageous features of high active surface area, good cation exchange ability and strong adsorption capacity. Under optimum conditions, this novel sensor showed a wide detection range for Pb2+ and Cd2+ (0.05–5.0 μM) with the limit of detection and limit of quantification for Pb2+ 0.01 and 0.03 μM, for Cd2+ 0.003 and 0.01 μM, respectively. It was successfully applied for the simultaneous determination of Pb2+ and Cd2+ in real water samples with satisfying recoveries of 93.6–105.3% for Pb2+ and 93.5–102.5% for Cd2+, demonstrating its feasibility for the determination of environmental metallic pollutants.

The Use of CeO2-TiO2 Nanocomposites as Enzyme Immobilization Platforms in Electrochemical Sensors

The use of metal oxide-based nanoparticles plays a key role in the development of electrochemical sensors with superior properties such as high sensitivity, wide linear range, low limit of detection, and long storage stability. In this work, we aimed to synthesize CeO 2 -TiO 2 mixed metal oxide nanoparticles which were used as substrate materials for the immobilization of biorecognition element for the construction of enzyme-based electrochemical sensors. For this purpose, in the first part of the study, CeO 2 -TiO 2 nanoparticles were prepared via a low temperature co-precipitation method and characterized using X-ray Diffraction (XRD), N 2 -adsorption, and Transmission Electron Microscopy (TEM) methods. The XRD results confirmed the successful synthesis of CeO 2 -TiO 2 mixed metal oxide nanoparticles with the average crystalline size of 8.51 nm. The calculated crystalline size value was compatible with that obtained from the TEM images. The N 2 adsorption results revealed a large surface area of 78.6 cm 2 g -1 which is essential for the construction of electrochemical sensors with improved performance. The electrochemical sensors were developed by the deposition of nanoparticles on the surface of a Pt electrode, followed by the immobilization of lactate oxide enzyme. The electrochemical performance of the sensors was evaluated by cyclic voltammetry (CV) and chronoamperometry methods. The constructed sensors showed a sensitivity of 0.085 ± 0.008 µA µM -1 cm -2 (n=5) with a high reproducibility (RSD % = 1.3) and a wide linear range (0.02-0.6 mM). In addition, the detection limit towards lactate was found be 5.9 µM. The results indicated that the use of CeO 2 -TiO 2 nanoparticles used as a modifier on the surface of the Pt electrode enabled the construction of electrochemical lactate sensors with high sensitivity.

An Overview of Pesticide Monitoring at Environmental Samples Using Carbon Nanotubes-Based Electrochemical Sensors

Carbon nanotubes have received enormous attention in the development of electrochemical sensors by promoting electron transfer reactions, decreasing the work overpotential within great surface areas. The growing concerns about environmental health emphasized the necessity of continuous monitoring of pollutants. Pesticides have been successfully used to control agricultural and public health pests; however, intense use can cause a number of damages for biodiversity and human health. In this sense, carbon nanotubes-based electrochemical sensors have been proposed for pesticide monitoring combining different electrode modification strategies and electroanalytical techniques. In this paper, we provide a review of the recent advances in the use of carbon nanotubes for the construction of electrochemical sensors dedicated to the environmental monitoring of pesticides. Future directions, perspectives, and challenges are also commented.

Comparison of different carbon nanostructures influence on potentiometric performance of carbon paste electrode

Recently, different carbon nanomaterials were introduced for construction of electrochemical sensors. In this study, the influence of carbon nanomaterial on performance of carbon paste potentiometric electrode was investigated. In this manner, different kinds of carbon nanomaterial, i.e., graphene, graphene oxide and carbon nanotube (CNT) were used as a conduction phase in carbon paste electrode. Then, potentiometric characteristics of the corresponding paste electrodes such as calibration slope, linear range, detection limit, response time and stability were compared with each other. The results appeared comprehensive findings about the role of electrode’s content in electrochemical performance.

Synthesis of Surface Molecularly Imprinted Poly(methacrylic acid-hemin) on Carbon Nanotubes for the Voltammetric Simultaneous Determination of Antioxidants from Lipid Matrices and Biodiesel

This paper reports the synthesis of novel nanocomposite based on multi-walled carbon nanotubes (MWCNT) covalently bonded by molecularly imprinted poly(methacrylic acid-hemin) (MIP-MWCNT) using tert-butylhydroquinone (TBHQ) as template molecule and its use in the construction of electrochemical sensor. Chemical, physical and morphological structure of nanocomposite was characterized by FT-IR, TGA, SEM, TEM and textural analysis. The electrochemical sensor highly selective to TBHQ was prepared by drop-casting a suspension of nanocomposite on the surface of a glassy carbon electrode. From cyclic voltammetry, it was observed that the electrochemical sensor modified with MIP-MWCNT exhibited great recognition performance, higher analytical response and catalytic properties towards the TBHQ when compared to NIP-MWCNT (nanocomposite polymerized without adding TBHQ), MIP-MWCNT without hemin and MIP-hemin without MWCNT. Such results demonstrated the synergic effect of imprinting influence, MWCNT and hemin in improving the performance of electrochemical sensor. From chronoamperometric measures, the electrochemical sensor modified with MIP-MWCNT could recognize TBHQ selectively in the presence of electroactives and structurally similar compounds. Under optimized conditions by pulse differential voltammetry (pulse amplitude of 100mV, pulse time of 25ms and scan rate of 10mVs−1) and measures in 0.15molL−1H2SO4, the proposed method successfully enabled the simultaneous determination of TBHQ and butylated hydroxyanisole (BHA), yielding limits of detection of 0.85 and 0.50μmolL−1, respectively. The feasibility of the method was checked by simultaneous determination of TBHQ and BHA in soybean oil, margarine, mayonnaise and biodiesel, whose results were statistically equal to those achieved by high performance liquid chromatography (HPLC).

Electrochemical Sensors Based on Molybdenum Disulfide Nanomaterials

AbstractNanostructured molybdenum disulfide (MoS2) has been arousing great research interest in many fields in recent years due to their peculiar properties. In this short review, we introduce recent advances in nanostructured MoS2 as potential materials for construction of electrochemical sensors. The potential application prospect of the electrochemical sensors based on MoS2 nanomaterials is proposed.

Formation of flowerlike gold nanostructure on ordered mesoporous carbon electrode and its application in electrochemical determination of ractopamine

Via an electrodeposition process, flowerlike gold nanostructure was formed on an ordered mesoporous carbon electrode surface. The morphology and kinetic characteristics of this gold/ordered mesoporous carbon composite material were characterized with scanning electron microscope and cyclic voltammograms. To further discover the potential application of the present material, an electrochemical sensor toward ractopamine determination was constructured. The satisfying evaluation results of the sensor indicated that the material is expected to be used in the design and construction of electrochemical sensors.

Sensing Properties of Multiwalled Carbon Nanotubes Grown in MW Plasma Torch: Electronic and Electrochemical Behavior, Gas Sensing, Field Emission, IR Absorption

Vertically aligned multi-walled carbon nanotubes (VA-MWCNTs) with an average diameter below 80 nm and a thickness of the uniform VA-MWCNT layer of about 16 μm were grown in microwave plasma torch and tested for selected functional properties. IR absorption important for a construction of bolometers was studied by Fourier transform infrared spectroscopy. Basic electrochemical characterization was performed by cyclic voltammetry. Comparing the obtained results with the standard or MWCNT‐modified screen-printed electrodes, the prepared VA-MWCNT electrodes indicated their high potential for the construction of electrochemical sensors. Resistive CNT gas sensor revealed a good sensitivity to ammonia taking into account room temperature operation. Field emission detected from CNTs was suitable for the pressure sensing application based on the measurement of emission current in the diode structure with bending diaphragm. The advantages of microwave plasma torch growth of CNTs, i.e., fast processing and versatility of the process, can be therefore fully exploited for the integration of surface-bound grown CNTs into various sensing structures.

Highly stable pyridinic nitrogen doped graphene modified electrode in simultaneous determination of hydroquinone and catechol

A highly stable pyridinic nitrogen doped graphene (pyridine-NG) was used as an excellent electrocatalyst for the construction of electrochemical sensor for simultaneous determination of hydroquinone (HQ) and catechol (CC) in 0.20M pH 5.5 acetate buffer solution. At the pyridine-NG modified electrode, both HQ and CC can cause a pair of quasi-reversible redox peaks and the potential difference of oxidation peaks between HQ and CC was 103mV. Under the optimized condition, the oxidation peak current of HQ was linear over the range from 5 to 200μM in the presence of 100μM CC, and the oxidation peak current of CC was linear over the range from 5 to 200μM in the presence of 100μM HQ. The detection limit is 0.38μM for HQ and 1μM for CC (S/N=3). This proposed sensor was successfully applied to the simultaneous determination of HQ and CC in artificial sample, and the results were good stability and high reproducibility. The excellent electrocatalysis of pyridine-NG can be due to the π–π interactions between the benzene ring of CC and graphene layer, the hydrogen bonds formed between hydroxyl in HQ molecule and pyridinic nitrogen atoms within graphene layers, especially the less density distribution of π electron cloud in pyridinic-NG in acidic condition.