Electro-oxidation of captopril at a gold electrode and its determination in pharmaceuticals and human fluids

2015 ◽  
Vol 7 (20) ◽  
pp. 8673-8682 ◽  
Author(s):  
Nagaraj P. Shetti ◽  
Shweta J. Malode ◽  
Sharanappa T. Nandibewoor
Keyword(s):  
Gold Electrode ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Chemical Parameters ◽  
Buffer Solution ◽  
Solution Ph ◽  
Physico Chemical ◽  
Electro Oxidation ◽  
Pulse Voltammetry ◽  
Human Fluids

Gold electrode was used for the oxidation of captopril in phosphate buffer solution pH 3.6 to study the influence of several physico-chemical parameters like potential, scan rate, pH and concentration by cyclic, linear sweep and differential pulse voltammetry.

scholarly journals Polyaniline-Invertase-Gold Nanoparticles Modified Gold Electrode for Sucrose Detection

2015 ◽  
Vol 15 (3) ◽  
pp. 226-233 ◽  
Author(s):  
Fitriyana Fitriyana ◽  
Fredy Kurniawan
Keyword(s):  
Gold Nanoparticles ◽  
Gold Electrode ◽  
Sucrose Solution ◽  
Sucrose Concentration ◽  
Phosphate Buffer Solution ◽  
Layer By Layer ◽  
Buffer Solution ◽  
Solution Ph ◽  
Active Materials ◽  
Aniline Polymerization

Sucrose sensor has been made by deposited the active materials on the surface of gold electrode. The active materials, i.e. polyaniline (PANI), invertase and gold nanoparticles, were deposited step by step. Aniline polymerization were conducted electrochemically at potential -500 to 1000 mV using voltammetry method with sweep rate 50 mV/s for 20 cycles in HCl solution pH 1.5. The modified electrode obtained was immersed in invertase 1 M phosphate buffer solution pH 6. The invertase trapping in polyaniline was performed using the same condition as aniline polymerization. Then, gold nanoparticles were deposited on the polyaniline-invertase modified gold electrode using Layer by Layer (LbL) technique. The polyaniline-invertase-gold nanoparticles modified gold electrode obtained was used to measure sucrose solution. Electrochemical signal of polyaniline (PANI)-invertase-gold nanoparticles modified gold electrode is increase with sucrose concentration. The sensitivity and detection limit of the electrode are 0.4657 µA mm-2 mM-1 and 9 µM, respectively. No electrochemical interference signals from fructose and glucose have been observed in the sucrose measurement.

Sensitive Determination of Epinephrine in the Presence of Ascorbic Acid at Poly(diphenylamine sulfonic acid) Modified Sensor

2020 ◽  
Vol 18 (4) ◽  
pp. 253-258
Author(s):  
Gamze Erdoğdu
Keyword(s):  
Ascorbic Acid ◽  
Sulfonic Acid ◽  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Buffer Solution ◽  
Sensitive Determination ◽  
Pulse Voltammetry ◽  
Modified Sensor

A sensitive and simple modified sensor was prepared by electrodeposition of diphenylamine sulfonic acid (DPSA) to the glassy carbon electrode surface by cyclic voltammetry (CV) technique. The electrooxidation of epinephrine (EP) was accomplished by CV and differential pulse voltammetry at poly(DPSA) modified sensor. As a result of the findings, the current values were enhanced and both substances were separated at the modified sensor compared to the bare electrode. There was linearly between the oxidation current and concentration of EP from 0.2 to 100 μM in phosphate buffer solution at pH 7.0. The limit of detection was 5.0 nM and the sensitivity was 0.4205 μA/μM. The determination of EP was successfully and satisfactorily carried out in real samples such as human blood serum and urine at the poly(DPSA) sensor. To the best knowledge of this work, this is the first study that detect the EP in the presence of ascorbic acid at poly(DPSA) sensor in the literature.

Glucose electro-oxidation on Pt(100) in phosphate buffer solution (pH 7): A mechanistic study

2020 ◽  
Vol 354 ◽  
pp. 136765 ◽  
Author(s):  
Gisele A.B. Mello ◽  
William Cheuquepán ◽  
Valentín Briega-Martos ◽  
Juan M. Feliu
Keyword(s):  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Mechanistic Study ◽  
Buffer Solution ◽  
Solution Ph ◽  
Electro Oxidation

Nafion/Quercetin/Graphene Composite-Modified Glassy Electrode for Selective and Sensitive Detection of Dopamine

2013 ◽  
Vol 641-642 ◽  
pp. 841-844
Author(s):  
Dai Min Song ◽  
Jian Fei Xia ◽  
Zong Hua Wang ◽  
Yan Zhi Xia ◽  
Fei Fei Zhang ◽  
...  
Keyword(s):  
Modified Electrode ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Sensitive Detection ◽  
Carbon Electrode ◽  
Good Reproducibility ◽  
Oxidation Peak ◽  
Buffer Solution ◽  
Graphene Composite ◽  
Pulse Voltammetry

Glassy carbon electrode (GCE) was modified using graphene (G), quercetin (Qu) and Nafion in this sequence to fabricate Nafion-Qu-G composite-modified GCE (Nafion/Qu/G/GCE). The as-prepared modified electrode combining the advantages of Nafion, Qu and G was employed for the selective and sensitive detection of dopamine (DA) in the presence of ascorbic acid (AA) and uric acid (UA). Compared with GCE, Qu/GCE, G/GCE and Qu/G/GCE, the Nafion/Qu/G/GCE was more electroactive and selective for DA. Differential pulse voltammetry (DPV) was used for electrochemical detection, the separations of the oxidation peak potentials for AA-DA and DA-UA were about 304 mV and 136 mV, which allowed selectively determining DA. In phosphate buffer solution (PBS) of pH 6.8, the Nafion/Qu/G/GCE provided a detection limit of 2.31×10-8 mol/L (S/N=3) for DA. Linearity (R=0.9963) of the peak currents against the concentration of DA was found over the range of 1.0×10-7 to 1.0×10-3 mol/L. Furthermore, the modified electrode exhibited good reproducibility and stability.

Inhibition of the Growth of Au Nanoparticles for Xanthine Sensing: Spectral and Electrochemical Studies on the Interactions between Xanthine and Au(III) Ions

2011 ◽  
Vol 239-242 ◽  
pp. 1562-1567
Author(s):  
Hong Cheng Pan ◽  
Dun Nan Li ◽  
Jiang Tao Liu ◽  
Jian Ping Li ◽  
Wen Yuan Zhu ◽  
...  
Keyword(s):  
Au Nanoparticles ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Resonance Light Scattering ◽  
Conditional Stability ◽  
Buffer Solution ◽  
Pulse Voltammetry ◽  
Conditional Stability Constants ◽  
Absorbance Band

The role of xanthine in the growth process of Au nanoparticles (AuNPs) was clarified by Uv-vis absorption spectra, resonance light scattering (RLS) spectra, cyclic votlammetry (CV), and differential pulse voltammetry (DPV). In a growth solution containing 0.01 M phosphate buffer solution (PBS, pH 7.4), 24.3 μM HAuCl4, and 2 mM cetyltrimethylammonium chloride (CTAC), the AuNPs were produced by tannic acid (TA) reduction. The growth of AuNPs was inhibited by the addition of xanthine. The plasmon absorbance band of AuNPs is blue shifted, indicating that larger sized AuNPs were grown in the presence of xanthine. Both the absorbance at 555 nm and RLS intensity at 652 nm of the grown AuNPs decreased linearly with increasing concentrations of xanthine. The linear regression equation are A=1.865−0.016 Cxanthine and I=397.8−4.617Cxanthine for absorbance and RLS intensity, respectively. The results of CV and DPV reveal that the inhibition effect of xanthine on the growth of AuNPs may attribute to the formation of xanthine-Au(III) complex. The conditional stability constants of the complexes were determined to be 2.22×105.

Metal-Modulated Growth of Au Nanoparticles by Electropolymerized 8-Hydroxyquinoline Films

2012 ◽  
Vol 503-504 ◽  
pp. 334-337
Author(s):  
Hong Cheng Pan ◽  
Wei Hong Liu ◽  
Xue Peng Li ◽  
Yan Bin Ren ◽  
Shan Hu Liu
Keyword(s):  
Indium Tin Oxide ◽  
Au Nanoparticles ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Au Nanoparticle ◽  
Buffer Solution ◽  
Ito Electrode ◽  
Glass Slides ◽  
Ito Glass ◽  
Pulse Voltammetry

8-hydroxyquinoline (8-Hq) films were electropolymerized on indium-tin-oxide-coated (ITO) glass slides by using cyclic voltammetry. The 8-Hq electropolymerized on ITO electrode (8-Hq/ITO) was immersed in a 5-mL solution containing 0.01 M phosphate buffer solution (PBS, pH 7.0), 0.8 mM cetyltrimethylammonium chloride, 20 µL of HAuCl4 (1%, w/w), and 50 µL of Au nanoparticle seeds. The mixture was incubated at 57oC for 3 h. Then Au nanoparticles were grown and deposited onto the 8-Hq/ITO electrode. It was found that some metal ions (Zn2+, Cd2+, Mg2+, and Pb2+) could inhibit the growth of Au nanoparticles. The metal-modulated growth of Au nanoparticles was studied by UV-vis spectra and differential pulse voltammetry.

scholarly journals Electrocatalytic activity for dopamine of silver nanoparticle onto graphene/poly(1,8-diaminonaphthalene) electrodes

2020 ◽  
Vol 9 (1) ◽  
pp. 111-115
Author(s):  
Hung Giap Van ◽  
Huy Nguyen Le ◽  
Van Bui Thi Hong ◽  
Dung Nguyen Tuan ◽  
Mai Nguyen Thi Tuyet
Keyword(s):  
Electrocatalytic Activity ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Modified Glassy Carbon Electrode ◽  
Buffer Solution ◽  
Structural Morphology ◽  
Graphene Composite ◽  
Novel Approach ◽  
Pulse Voltammetry

In this research, we report on the synthesis and electrochemical characterization of a poly(1,8-diaminonaphthalene)/graphene composite film which is capable to adsorb Ag+ ions toward to the dopamine sensing application. The present of graphene significantly improved the structural morphology and electrochemical activities of the pristine polymer, the adsorption capacity for Ag+ ions and the conductivities of the composite were enhanced. The graphene/poly(1,8-diaminonaphthalene)-Ag modified glassy carbon electrode was used to the ability of electrocatalytic activity dopamine in phosphate buffer solution by differential pulse voltammetry. The results open up the path for designing other dopamine sensing based on our novel approach.

scholarly journals Electrochemical Polymerised Graphene Paste Electrode and Application to Catechol Sensing

2019 ◽  
Vol 13 (1) ◽  
pp. 81-87 ◽  
Author(s):  
Jamballi G. Manjunatha
Keyword(s):  
Modified Electrode ◽  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Sample Pretreatment ◽  
Differential Pulse ◽  
Buffer Solution ◽  
Solution Ph ◽  
Graphene Paste Electrode ◽  
Paste Electrode

Objective: To build up an advantageous strategy for sensitive determination of catechol (CC), a poly (proline) modified graphene paste electrode (PPMGPE) was fabricated and used as a voltammetric sensor for the determination of CC. Methods: The performance of the modified electrode was studied using cyclic voltammetric (CV) and differential pulse voltammetric method (DPV). The modified electrode was characterized by CV and DPV. The surface of the modified electrode was examined by FESEM. The electrochemical behavior of CC in phosphate buffer solution (pH 7.5) was inspected using bare graphene paste electrode (BGPE) and PPMGPE. Results & Conclusion: The PPMGPE shows a lower limit of detection, calculated to be 8.7×10–7mol L−1 (S/N=3). This modified electrode was applied successfully for the determination of CC in water samples without applying any sample pretreatment.

Electrochemical Determination of Norepinephrine at Poly (p-aminobenzenesulfonic Acid) Modified Sensor

2020 ◽  
Vol 16 (5) ◽  
pp. 591-600
Author(s):  
Şevket Zişan Yağcı ◽  
Ebru Kuyumcu Savan ◽  
Gamze Erdoğdu
Keyword(s):  
Ascorbic Acid ◽  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Electrochemical Determination ◽  
Buffer Solution ◽  
Oxidation Current ◽  
Pulse Voltammetry ◽  
Modified Sensor

Objective: In this study, it was aimed to prepare an electrochemical sensor capable of assigning Norepinephrine in the presence of an interference such as ascorbic acid. Methods: A sensitive modified sensor was prepared by electrodeposition of p-aminobenzenesulfonic acid (p-ABSA) to the glassy carbon electrode by cyclic voltammetry. The electrooxidation of Norepinephrine was accomplished by cyclic and differential pulse voltammetry. Results: The current values were enhanced and the peak potentials of Norepinephrine and ascorbic acid were separated at the sensor compared to the bare electrode. There was linearity between the oxidation current and concentration of Norepinephrine ranging from 0.5 to 99.8 μM in phosphate buffer solution at pH 7.0. The limit of detection was 10.0 nM and the sensitivity was 0.455 μA/μM. Conclusion: The determination of Norepinephrine was successfully performed in real samples such as blood serum and urine at the poly (p-ABSA) sensor. To the best of our knowledge, this is the first study to detect Norepinephrine in the presence of ascorbic acid at poly (p-ABSA) modified sensor in the literature.

Electrochemical characterization of luminol and its determination in real samples

2014 ◽  
Vol 6 (19) ◽  
pp. 7809-7813 ◽  
Author(s):  
Gulcemal Yildiz ◽  
Ugur Tasdoven ◽  
Necati Menek
Keyword(s):  
Cyclic Voltammetry ◽  
Glassy Carbon ◽  
Electrochemical Behavior ◽  
Differential Pulse ◽  
Carbon Electrode ◽  
Buffer Solution ◽  
Solution Ph ◽  
Real Samples ◽  
Pulse Voltammetry

The electrochemical behavior of luminol, an important molecule in forensic science, was studied in Britton–Robinson buffer solution (pH 2–pH 13) at a glassy carbon electrode using cyclic voltammetry and differential pulse voltammetry techniques.

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