scholarly journals Assessing Surface Coverage of Aminophenyl Bonding Sites on Diazotised Glassy Carbon Electrodes for Optimised Electrochemical Biosensor Performance

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 416
Author(s):  
Zari Tehrani ◽  
Hina Yaqub Abbasi ◽  
Anitha Devadoss ◽  
Jonathan Edward Evans ◽  
Owen James Guy
Keyword(s):  
Carboxylic Acid ◽  
Surface Coverage ◽  
Electrochemical Biosensor ◽  
Electrochemical Techniques ◽  
Differential Pulse ◽  
Second Step ◽  
Glassy Carbon Electrodes ◽  
Potential Marker ◽  
Pulse Voltammetry ◽  
Amine Coupling

Electrochemical biosensors using carbon-based electrodes are being widely developed for the detection of a range of different diseases. Since their sensitivity depends on the surface coverage of bioreceptor moieties, it necessarily depends on the surface coverage of amine precursors. Electrochemical techniques, using ferrocene carboxylic acid as a rapid and cheap assay, were used to assess the surface coverage of amino-phenyl groups attached to the carbon electrode. While the number of electrons transferred in the first step of diazotisation indicated a surface coverage of 8.02 ± 0.2 × l0−10 (mol/cm2), and those transferred in the second step, a reduction of nitrophenyl to amino-phenyl, indicated an amine surface coverage of 4–5 × l0−10 (mol/cm2), the number of electrons transferred during attachment of the amine coupling assay compound, ferrocene carboxylic acid, indicated a much lower available amine coverage of only 2.2 × l0−11 (mol/cm2). Furthermore, the available amine coverage was critically dependent upon the number of cyclic voltammetry cycles used in the reduction, and thus the procedures used in this step influenced the sensitivity of any subsequent sensor. Amine coupling of a carboxyl terminated anti-beta amyloid antibody specific to Aβ(1-42) peptide, a potential marker for Alzheimer’s disease, followed the same pattern of coverage as that observed with ferrocene carboxylic acid, and at optimum amine coverage, the sensitivity of the differential pulse voltammetry sensor was in the range 0–200 ng/mL with the slope of 5.07 µA/ng·mL−1 and R2 = 0.98.

Ultrasensitive Electrochemical Determination of Phosphate in water by Hydrophilic TiO2 modified Glassy Carbon Electrodes

2021 ◽  
Author(s):  
Yan Jin ◽  
Tong QI ◽  
Yuqing Ge ◽  
Jin Chen ◽  
Li juan Liang ◽  
...  
Keyword(s):  
Differential Pulse Voltammetry ◽  
Glassy Carbon ◽  
Differential Pulse ◽  
Electrochemical Determination ◽  
Carbon Electrodes ◽  
Glassy Carbon Electrodes ◽  
Time Differential ◽  
Pulse Voltammetry ◽  
First Time

In this paper, ultrasensitive electrochemical determination of phosphate in water is achieved by hydrophilic TiO2 modified glassy carbon electrodes for the first time. Differential pulse voltammetry (DPV) method is proposed...

scholarly journals Development of an Electrochemical Biosensor for Rapid and Effective Detection of Pathogenic Escherichia coli in Licorice Extract

2019 ◽  
Vol 9 (2) ◽  
pp. 295 ◽  
Author(s):  
Haixia Wang ◽  
Yuwen Zhao ◽  
Songtao Bie ◽  
Tongchuan Suo ◽  
Guangcheng Jia ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Electrochemical Biosensor ◽  
Linear Trend ◽  
Differential Pulse ◽  
E Coli ◽  
Pathogenic Escherichia Coli ◽  
Colony Forming Units ◽  
Relative Standard ◽  
Licorice Extract ◽  
Pulse Voltammetry

An aptamer-based electrochemical biosensor was successfully developed and applied in the rapid detection of pathogenic Escherichia coli (E. coli) in licorice extract. The thiolated capture probes were firstly immobilized on a gold electrode, and then the biotinylated aptamer probes for E. coli were introduced by hybridization with the capture probes. Due to the stronger interaction between the aptamer and the E. coli, a part of the biotinylated aptamers will dissociate from the capture probes in the presence of E. coli. The residual biotinylated aptamer probes can quantitatively bind with streptavidin-alkaline phosphatase. Subsequently, α-naphthyl phosphate substrate was catalytically hydrolyzed to generate electrochemical response, which could be recorded by a differential pulse voltammetry. The dependence of the peak current on the logarithm of E. coli concentration in the range from 5.0 × 102 colony forming units (CFU)/mL to 5.0 × 107 CFU/mL exhibited a linear trend with a detection limit of 80 CFU/mL. The relative standard deviation of 5 successive scans was 5.3%, 4.5% and 1.1% for 5.0 × 102, 5.0 × 105 and 5.0 × 107 CFU/mL E. coli, respectively. In the detection of the licorice extract samples, the results obtained from the proposed strategy and traditional culture counting method were close to each other, but the time consumption was only ~1/30 compared with the traditional method. These results demonstrate that the designed biosensor can be potentially utilized for rapid microbial examination in traditional Chinese medicine and relevant fields.

Magnetic Mesoporous Silica/Chitosan/Polyproline: A Novel Nanocomposite Toward Sensing of Some Clinically Relevant Biomolecules

Nano LIFE ◽  
2017 ◽  
Vol 07 (03n04) ◽  
pp. 1750006 ◽  
Author(s):  
Mohammad Hasanzadeh ◽  
Soodabeh Hassanpour ◽  
Arezoo Saadati ◽  
Nasrin Shadjou ◽  
Ahad Mokhtarzadeh
Keyword(s):  
Mesoporous Silica ◽  
Surface Coverage ◽  
Linear Sweep Voltammetry ◽  
Differential Pulse ◽  
One Step ◽  
Pulse Voltammetry ◽  
Small Biomolecules ◽  
Magnetic Mesoporous Silica ◽  
Mcm 41

In this paper, free-radical polymerization inside magnetic mesoporous silica has been investigated in order to open a route to functional polymer–silica composite nanomaterials with well-defined mesoporosity. Proline monomers integrated with chitosan (CS) were electropolymerized into amino-functionalized magnetic mesoporous silica. The fabrication of polyproline-amino-functionalized magnetic mesoporous silica–CS nanohybrid on glassy carbon electrode (GCE) was performed using one step electrodeposition regime. Field emission scanning electron microscopy (FE-SEM) was confirmed as produced nanohybrid material containing polyproline (PPR) into the pores of magnetic (Fe3O[Formula: see text] mobile crystalline material-41 grafted with 3-aminopropyl groups (MMS) which leads to increase of surface coverage of PPR. The results indicate that PPR was successfully generated inside the pores of the amino-functionalized Mobil Composition of Matter No. 41 (nPrNH2-MCM-41) and that the amine group was capable of protonating the polymer, producing polyproline, the most conductive one, without the addition of another acid source during the polymerization step. Therefore, it was evaluated some electrochemical aspects of the prepared nanohybrid using cyclic voltammetry, differential pulse voltammetry and linear sweep voltammetry. Finally, the electroactivity of polyproline -Fe3O4-nPrNH2-MCM-41-chitosan nanohybrid (PPR-MMS-CS) modified GCE toward detection and determination of some clinically relevant small biomolecules was studied.

scholarly journals Electrochemical Behavior and Voltammetric Determination of a Manganese(II) Complex at a Carbon Paste Electrode

2016 ◽  
Vol 11 ◽  
pp. ACI.S32150 ◽  
Author(s):  
Sophia Karastogianni ◽  
Stella Girousi
Keyword(s):  
Carboxylic Acid ◽  
Differential Pulse Voltammetry ◽  
Carbon Paste Electrode ◽  
Electrochemical Behavior ◽  
Differential Pulse ◽  
Carbon Paste ◽  
Oxidation Reduction ◽  
Pulse Voltammetry ◽  
Paste Electrode

Investigation of the electrochemical behavior using cyclic voltammetry and detection of [Mn2+(thiophenyl-2-carboxylic acid)2 (triethanolamine)] with adsorptive stripping differential pulse voltammetry. The electrochemical behavior of a manganese(II) complex [Mn2+(thiophenyl-2-carboxylic acid)2(triethanolamine)] (A) was investigated using cyclic and differential pulse voltammetry in an acetate buffer of pH 4.6 at a carbon paste electrode. Further, an oxidation-reduction mechanism was proposed. Meanwhile, an adsorptive stripping differential pulse voltammetric method was developed for the determination of manganese(II) complex.

scholarly journals Ru(terpy)-Based Conducting Polymer in Electrochemical Biosensing of Epinephrine

2021 ◽  
Vol 11 (5) ◽  
pp. 2065
Author(s):  
Francesca Meloni ◽  
Maria I. Pilo ◽  
Gavino Sanna ◽  
Nadia Spano ◽  
Antonio Zucca
Keyword(s):  
Conducting Polymer ◽  
Differential Pulse ◽  
Pharmaceutical Products ◽  
Carbon Electrodes ◽  
Cross Linking ◽  
Glassy Carbon Electrodes ◽  
Electrochemical Biosensing ◽  
Pulse Voltammetry ◽  
Tyrosinase Enzyme

A heteroleptic [Ru(terpy)2]2+ (terpy = 2,2′:6′,2″-terpyridine) complex was electrochemically polymerized to give the corresponding metal-containing conducting polymer on gold and glassy carbon electrodes. The polymerization of the Ru(II) complex was allowed by a terthiophene functionalization on one of the two terpy coordinating fragments, whereas the presence of -COOH substituents on the second terpy ligand enabled the film to immobilize a tyrosinase enzyme by cross-linking with glutaraldehyde. Then, the Ru(terpy) conducting polymer worked as a transducer as well as an immobilizing agent in the design of amperometric biosensors for the determination of epinephrine. The electrochemical behavior of enzymatic sensors containing Ru(terpy)-based conducting polymers was investigated by differential pulse voltammetry and chronoamperometry. Analytical performances and kinetic parameters were calculated, suggesting a potential application of the reported biosensors in the determination of epinephrine in pharmaceutical products.

ELECTROCHEMICAL INVESTIGATION OF DA AND UA ON CARBOXYLATED GRAPHENE OXIDE/LANTHANUM ELECTRODES WITH SUNDRY CONTENT OF CTAB

2017 ◽  
Vol 24 (07) ◽  
pp. 1750097 ◽  
Author(s):  
J. JIANG ◽  
L. ZHU ◽  
W. QIAN ◽  
H. CHEN ◽  
C. FENG ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Ph Value ◽  
Differential Pulse ◽  
Ammonium Bromide ◽  
Electrochemical Investigation ◽  
Glassy Carbon Electrodes ◽  
Real Samples ◽  
Electro Oxidation ◽  
Pulse Voltammetry ◽  
Optimized Conditions

Glassy carbon electrodes (GCE) were modified by carboxylated graphene oxide/lanthanum with various concentrations of hexadecyl trimethyl ammonium bromide (CTAB), and the treated electrodes, called CTAB/GO-COOLa/GCE, were prepared for the detection of uric acid (UA) and dopamine (DA) by using the differential pulse voltammetry (DPV) and the cyclic voltammetry (CV). The results show that the modified electrode’s electrocatalytic activity could be affected by several factors in the examination, they are the pH value of the system, the main content of CTAB, various concentrations and rates of scan. With a combination of carboxylated graphene oxide/lanthanum and CTAB, the resulted CTAB/GO-COOLa/GCE sensors showed preeminent selectivity and obvious catalytic property toward the electro-oxidation of UA and DA. In optimized conditions, the response of the CTAB/GO-COOLa/GCE electrode for DA was linear in the region of 0.03–500.0[Formula: see text][Formula: see text]M with detection limits of 0.036[Formula: see text][Formula: see text]M [Formula: see text]. Two linear response ranges for the determination UA were obtained from ranges of 1 to 200[Formula: see text][Formula: see text]M and 200 to 1300[Formula: see text][Formula: see text]M with a detection limit of 0.42[Formula: see text][Formula: see text]M [Formula: see text]. Moreover, the refined electrode was used in the inspection of DA and UA in real samples of serum and urine successfully, displaying its potential application of real samples involved in electroanalysis.

scholarly journals Electroanalytical Characterisation of Dopa Decarboxylase Inhibitors Carbidopa and Benserazide on Multiwalled Carbon Nanotube and Poly(Nile blue A) Modified Glassy Carbon Electrodes

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Dilek Kul ◽  
Christopher M. A. Brett
Keyword(s):  
Differential Pulse Voltammetry ◽  
Glassy Carbon ◽  
Nile Blue ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Carbon Electrodes ◽  
Potential Cycling ◽  
Multiwalled Carbon ◽  
Glassy Carbon Electrodes ◽  
Pulse Voltammetry

Modified glassy carbon electrodes have been made by deposition of functionalised multiwalled carbon nanotubes (MWCNTs) followed by formation of poly(Nile blue) (PNB) films by electropolymerisation, using potential cycling in 0.1 M phosphate buffer solution (PBS) at pH 6.0. The electrochemical oxidation of carbidopa (CD) and benserazide (BS) on these MWCNTs/PNB-modified electrodes was investigated using cyclic and differential pulse voltammetry in 0.1 M PBS at different values of pH between 5.0 and 8.0; both CD and BS gave one diffusion-controlled irreversible oxidation peak in cyclic voltammetry. Analytical characterisation of CD and BS was carried out in 0.1 M PBS, pH 5.0. Peak currents in differential pulse voltammetry were linear over the concentration range of1×10−5to1×10−4 M for CD and4×10−6to4×10−5 M for BS. The repeatability, precision, and accuracy of the method were also investigated. Higher sensitivities and lower detection limits, of 1.17 μM for CD and 0.50 μM for BS, were obtained with this new modified electrode compared with previous studies reported in the literature.

scholarly journals Electrochemical Comparison on New (Z)-5-(Azulen-1-Ylmethylene)-2-Thioxo-Thiazolidin-4-Ones

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 588
Author(s):  
Eleonora-Mihaela Ungureanu ◽  
Mariana Popescu (Apostoiu) ◽  
Georgiana-Luiza Tatu (Arnold) ◽  
Liviu Birzan ◽  
Raluca Isopescu ◽  
...  
Keyword(s):  
Oxidation Mechanism ◽  
Stripping Voltammetry ◽  
Rotating Disk ◽  
Differential Pulse ◽  
Rotating Disk Electrode ◽  
Carbon Electrodes ◽  
Glassy Carbon Electrodes ◽  
Alkyl Groups ◽  
Rotating Disk Electrode Voltammetry ◽  
Pulse Voltammetry

Three (Z)-5-(azulen-1-ylmethylene)-2-thioxo-thiazolidin-4-ones are electrochemically characterized by cyclic voltammetry, differential pulse voltammetry, and rotating disk electrode voltammetry. The electrochemical investigations revealed that the redox potential is influenced by the number and position of the alkyl groups, and the possible oxidation mechanism is proposed. These compounds, after their immobilization on glassy carbon electrodes during oxidative electropolymerization, were examined as complexing ligands for heavy metal ions from aqueous solutions through adsorptive stripping voltammetry.

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