scholarly journals Disposable Multi-Walled Carbon Nanotubes-Based Plasticizer-Free Solid-Contact Pb2+-Selective Electrodes with a Sub-PPB Detection Limit †

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2550 ◽  
Author(s):  
Yueling Liu ◽  
Yingying Gao ◽  
Rui Yan ◽  
Haobo Huang ◽  
Ping Wang
Keyword(s):  
Carbon Nanotubes ◽  
Electrochemical Impedance Spectroscopy ◽  
Detection Limit ◽  
Electrochemical Impedance ◽  
Solid Contact ◽  
Water Films ◽  
Multi Walled Carbon Nanotubes ◽  
Nernstian Slope ◽  
Disk Electrodes ◽  
Walled Carbon Nanotubes

Potentiometric plasticizer-free solid-contact Pb2+-selective electrodes based on copolymer methyl methacrylate-n-butyl acrylate (MMA-BA) as membrane matrix and multi-walled carbon nanotubes (MWCNTs) as intermediate ion-to-electron transducing layer have been developed. The disposable electrodes were prepared by drop-casting the copolymer membrane onto a layer of MWCNTs, which deposited on golden disk electrodes. The obtained electrodes exhibited a sub-ppb level detection limit of 10−10 mol·L−1. The proposed electrodes demonstrated a Nernstian slope of 29.1 ± 0.5 mV/decade in the linear range from 2.0 × 10−10 to 1.5 × 10−3 mol·L−1. No interference from gases (O2 and CO2) or water films was observed. The electrochemical impedance spectroscopy of the fabricated electrodes was compared to that of plasticizer-free Pb2+-selective electrodes without MWCNTs as intermediated layers. The plasticizer-free MWCNTs-based Pb2+-selective electrodes can provide a promising platform for Pb(II) detection in environmental and clinical application.

scholarly journals Multi-walled carbon nanotubes/nano-Ag-TiO2 membrane DNA electrochemical biosensor

2019 ◽  
Author(s):  
Zhongguo Zheng ◽  
Lisa Schultz ◽  
John Smith
Keyword(s):  
Carbon Nanotubes ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Biosensor ◽  
Electrochemical Impedance ◽  
Carbon Paste ◽  
Dna Electrochemical Biosensor ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Paste Electrode

AbstractA highly sensitive DNA electrochemical biosensor was prepared based on multi-walled carbon nanotube/nano-Ag-TiO2 composite membrane. The Ag-TiO2 composite is mixed with a suitable amount of multi-walled carbon nanotubes (MWNT) dispersed in N,N-dimethylformamide to form a uniform and stable mixed solution, which is applied onto the surface of the bare carbon paste electrode. A MWNT/Ag-TiO2 modified carbon paste electrode was prepared. The large specific surface area and good electron transport properties of carbon nanotubes have a good synergistic effect on the good biocompatibility of Ag-TiO2 nanocomposites and excellent adsorption capacity of DNA, which significantly improves the immobilization and DNA hybridization of DNA probes. Detection sensitivity. The preparation of the sensing membrane and the immobilization and hybridization of DNA were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The exogenous glufosinate acetyltransferase gene fragment of transgenic plants was detected by electrochemical impedance spectroscopy. The linear range was 1. 0 × 10 - 11 ∼1. 0 × 10 - 6 mol / L. The detection limit was 3. 12 × 10 - 12 mol / L.

scholarly journals Electrodeposition of Sn and Sn Composites with Carbon Materials Using Choline Chloride-Based Ionic Liquids

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 798
Author(s):  
Ana T. S. C. Brandão ◽  
Liana Anicai ◽  
Oana Andreea Lazar ◽  
Sabrina Rosoiu ◽  
Aida Pantazi ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Materials ◽  
Electrochemical Impedance ◽  
Choline Chloride ◽  
Composite Films ◽  
Growth Stages ◽  
Initial Growth ◽  
Sem Images ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Nano carbons, such as graphene and carbon nanotubes, show very interesting electrochemical properties and are becoming a focus of interest in many areas, including electrodeposition of carbon–metal composites for battery application. The aim of this study was to incorporate carbon materials (namely oxidized multi-walled carbon nanotubes (ox-MWCNT), pristine multi-walled carbon nanotubes (P-MWCNT), and reduced graphene oxide (rGO)) into a metallic tin matrix. Formation of the carbon–tin composite materials was achieved by electrodeposition from a choline chloride-based ionic solvent. The different structures and treatments of the carbon materials will create metallic composites with different characteristics. The electrochemical characterization of Sn and Sn composites was performed using chronoamperometry, potentiometry, electrochemical impedance, and cyclic voltammetry. The initial growth stages of Sn and Sn composites were characterized by a glassy-carbon (GC) electrode surface. Nucleation studies were carried out, and the effect of the carbon materials was characterized using the Scharifker and Hills (SH) and Scharifker and Mostany (SM) models. Through a non-linear fitting method, it was shown that the nucleation of Sn and Sn composites on a GC surface occurred through a 3D instantaneous process with growth controlled by diffusion. According to Raman and XRD analysis, carbon materials were successfully incorporated at the Sn matrix. AFM and SEM images showed that the carbon incorporation influences the coverage of the surface as well as the size and shape of the agglomerate. From the analysis of the corrosion tests, it is possible to say that Sn-composite films exhibit a comparable or slightly better corrosion performance as compared to pure Sn films.

scholarly journals Cost-Effective Potentiometric Platforms Modified with Multi-Walled Carbon Nanotubes (MWCNTs) and Based on Imprinted Receptors for Fluvoxamine Assessment

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 673
Author(s):  
Heba M. Hashem ◽  
Saad S. M. Hassan ◽  
Ayman H. Kamel ◽  
Abd El-Galil E. Amr ◽  
E. M. AbdelBary
Keyword(s):  
Carbon Nanotubes ◽  
Electrochemical Impedance ◽  
Biological Fluids ◽  
Pharmaceutical Preparations ◽  
Cost Effective ◽  
Hplc Method ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Screen Printed

A simple, efficient and reliable analytical method was developed and used for the determination of the fluvoxamine drug (FLV) in pharmaceutical preparations and biological fluids. The method is based on the cost-effective screen-printed platform for the potential transduction of the drug. Host-tailored molecular imprinting polymer (MIP) was integrated with the potentiometric platform as a recognition receptor, in which FLV, acrylamide (AAm), ethylene glycol dimethacrylate (EGDMA) and acetonitrile were used as a template, functional monomer, cross-linker, and solvent, respectively. MIP particles were dispersed in plasticized poly (vinyl chloride) (PVC) and the membrane was drop-casted on carbon screen-printed electrode. The MIP, in addition to non-imprinted polymers (NIP), was characterized and the binding experiment revealed high affinity and adsorption capacity of MIP towards FLV. The proposed sensor displayed near-Nernstian cationic slope of 55.0 ± 0.8 mV/decade (r2 = 0.999) with a low detection limit of 4.8 × 10−6 mol/L over a wide pH range (3.0–8.5). The electrochemical features of the proposed sensors including electrochemical impedance spectroscopy (EIS) and chronopotentiometry measurements (CP) in the presence of multi-walled carbon nanotubes (MWCNTs) as a solid contact transducer were also investigated. The applications of the proposed sensor for the determination of FLV in different dosage forms with recovery values (98.8%–101.9%) and (97.4%–101.1%), respectively compared with the reference HPLC method with acceptedFandt-student tests values at the 95% confidence level.

Electrochemical Impedance Studies on Single and Multi-Walled Carbon Nanotubes—Polymer Nanocomposites for Biosensors Development

2015 ◽  
Vol 15 (5) ◽  
pp. 3385-3393 ◽  
Author(s):  
Mihaela Tertiş ◽  
Anca Florea ◽  
Bogdan Feier ◽  
Iuliu Ovidiu Marian ◽  
Luminţa Silaghi-Dumitrescu ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Polymer Nanocomposites ◽  
Electrochemical Impedance ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Preparation of Molecularly Imprinted Polypyrrole and Carbon Nanotubes Film Modified Electrode for Dopamine Recognition

2012 ◽  
Vol 578 ◽  
pp. 105-108 ◽  
Author(s):  
Fei Fei Zhang ◽  
Zong Hua Wang ◽  
Jian Fei Xia ◽  
Yan Zhi Xia ◽  
Feng Cai ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Modified Electrode ◽  
High Selectivity ◽  
Electrochemical Impedance ◽  
Good Sensitivity ◽  
Optimum Conditions ◽  
Molecularly Imprinted ◽  
Multi Walled Carbon Nanotubes ◽  
Overoxidized Polypyrrole ◽  
Walled Carbon Nanotubes

A novel film of overoxidized polypyrrole and carboxylic multi-walled carbon nanotubes (c-MWNTs) was fabricated with molecular imprinted technique for dopamine by a direct and facile electropolymerization method. The resulting modified electrode surface was characterized with electrochemical impedance spectroscopy and Fourier transform infrared spectroscopy. The results demonstrated that the modified electrode not only possessed a good sensitivity but also exhibited a high selectivity toward DA which making anodic potential difference of DA and AA is 318 mV in DPV. Under the optimum conditions, the linear range of the dopamine biosensor ranges from 5.0×10−8 to 6.0×10−6 mol/L with a detection limit of 5.0×10−9 mol/L

scholarly journals Voltammetric Amitriptyline Determination Using a Metal-Free Electrode Based on Phosphorus-Doped Multi-Walled Carbon Nanotubes

2022 ◽  
Author(s):  
Chanakarn Sanguarnsak ◽  
Kiattisak Promsuwan ◽  
Jenjira Saichanapan ◽  
Asamee Soleh ◽  
Kasrin Saisahas ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Electrochemical Sensing ◽  
Urine Samples ◽  
Electrochemical Characteristics ◽  
Sensing Element ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Phosphorus Doped

Abstract A new electrode material of phosphorus-doped multi-walled carbon nanotubes (P-MWCNTs) was developed as an electrochemical sensing element for amitriptyline (AMT). P-MWCNTs were hydrothermally synthesized and drop casted on a glassy carbon electrode (P-MWCNTs/GCE). The P-MWCNTs were morphologically, chemically and structurally characterized. The electrochemical characteristics of the P-MWCNTs/GCE were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and adsorptive stripping voltammetry (AdSV). The P-MWCNTs increased electron transfer at the GCE and the electrochemical conductivity of the electrode. Electrocatalytic activity toward the oxidation of AMT was excellent. In the optimal voltammetric condition, the P-MWCNTs/GCE produced linear ranges of 0.50 to 10 µg mL-1 and 10 to 40 µg mL-1. The limit of detection (LOD) and limit of quantification (LOQ) were 0.15 µg mL-1 (0.54 µM) and 0.52 µg mL-1 (1.80 µM), respectively. The developed sensor displayed good repeatability, reproducibility and specificity. The sensor successfully quantified AMT in pharmaceutical tablets, giving results consistent with spectrophotometric analysis. The sensor achieved recoveries from 98±2% to 101±5% from spiked urine samples. The proposed sensor could be applied to determine AMT in pharmaceutical and urine samples for forensic toxicology.

Molecularly Imprinted Electrochemical Sensor for the Determination of Sulfamethoxazole

2018 ◽  
Vol 21 (2) ◽  
pp. 077-080 ◽  
Author(s):  
Benzhi Liu ◽  
Guangqing Liu ◽  
Bo Xiao ◽  
Jinlong Yan
Keyword(s):  
Carbon Nanotubes ◽  
Detection Limit ◽  
Electrochemical Sensor ◽  
Carbon Electrode ◽  
Modified Glassy Carbon Electrode ◽  
Molecularly Imprinted ◽  
Real Samples ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

A selective and sensitive molecularly imprinted electrochemical sensor was prepared based on the electropolymerization of methylthionine chloride on the multi-walled carbon nanotubes modified glassy carbon electrode. The proposed sensor was applied to the determination of sulfamethoxazole which showed a linear range of 2.4 to 23.6 µM, and a detection limit of 0.81 µM.The determination of sulfamethoxazole in real samples was also studied.

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