scholarly journals Application of Fe3O4@SiO2/GO nanocomposite for sensitive and selective electrochemical sensing of tryptophan

2018 ◽  
Vol 9 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Hadi Beitollahi ◽  
Mohadeseh Safaei ◽  
Masoud Reza Shishehbore ◽  
Somayeh Tajik
Keyword(s):  
Differential Pulse ◽  
Electrochemical Sensing ◽  
Oxidation Peak ◽  
Screen Printed Electrode ◽  
Experimental Conditions ◽  
Catalytic Activities ◽  
Simple Strategy ◽  
Lower Detection ◽  
Pulse Voltammetry

A simple strategy for determination of tryptophan (TRP) based on Fe3O4@SiO2/GO nano­composite modified graphite screen printed electrode (Fe3O4@SiO2/GO/SPE) is re­ported. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to characterize the performance of the sensor. The Fe3O4@SiO2/GO/SPE displayed excellent electro­che­mical catalytic activities. The oxidation overpotentials of tryptophan decreased significantly and its oxidation peak current increased dramatically at Fe3O4@SiO2/GO/SPE. Under the optimized experimental conditions tryptophan showed linear response over the range of 1.0-400.0 μM. The lower detection limit was found to be 0.2 μM for tryptophan. The prac­tical application of the modified electrode was demonstrated by measuring the concen­tration of tryptophan in real samples.

scholarly journals A novel vitamin B9 sensor based on modified screen-printed electrode

2020 ◽  
Author(s):  
Hamid Sarhadi ◽  
Zare Maryam
Keyword(s):  
High Stability ◽  
High Sensitivity ◽  
Differential Pulse ◽  
Current Response ◽  
Oxidation Peak ◽  
Screen Printed Electrode ◽  
Vitamin B9 ◽  
Pulse Voltammetry ◽  
Screen Printed

In the field of determination of vitamin B9 (folic acid, FA), we have described the development of a sensitive electrochemical sensor through promoting the screen-printed electrode (SPE) and taking the advantage of zinc ferrite magnetic nanoparticles (ZnFe2O4MNPs). Cyclic voltammetry (CV) experiments demonstrated the powerful activity of ZnFe2O4MNPs/SPE for electrooxidation of FA by showing the prominent oxidation peak at 600 mV vs. Ag/AgCl. By differential pulse voltammetry (DPV) measurements, a linear relation between current response and concentration of vitamin B9 was determined in the range of 1.0–100.0 µM, and detection limit is found to be 0.3 µM (S/N=3). Except high sensitivity, the developed sensor demonstrated high stability, reproducibility and repeatability, and was also successfully applied to specify FA in real samples of vitamin B9 tablets and human urine.

scholarly journals Simultaneous electrochemical determination of acetaminophen and metoclopramide at electrochemically pre-treated disposable graphite pencil electrode

2016 ◽  
Vol 6 (3) ◽  
pp. 265 ◽  
Author(s):  
Shreekant M Patil ◽  
Vijay P Pattar ◽  
Sharanappa T Nandibewoor
Keyword(s):  
Simultaneous Determination ◽  
Differential Pulse ◽  
Electrochemical Determination ◽  
Experimental Conditions ◽  
Positive Direction ◽  
Oxidation Potentials ◽  
Voltammetric Behavior ◽  
Pulse Voltammetry ◽  
Apparent Shift

<p class="PaperAbstract"><span lang="EN-US">A sensitive and economic voltammetric method was developed for the simultaneous determination of acetaminophen (AMP) and metoclopramide (MCP) using pre-treated graphite pencil electrode (PTGPE). Compared to a graphite pencil electrode, the pre-treated electrode showed an apparent shift of the oxidation potentials in the positive direction and a notable enhancement in the current responses for both AMP and MCP. Cyclic voltammetry (CV) was used to study the voltammetric behavior of the drugs, while differential pulse voltammetry (DPV) was used to determine AMP and MCP simulta­neously. The dependence of the current on scan rate, pH and concentration was investi­gated to boost the experimental conditions for simultaneous determination. The calibra­tion curves were obtained over the range of 0.1</span><span lang="EN-US">×</span><span lang="EN-US">10<sup>-7</sup> to 1.1</span><span lang="EN-US">×</span><span lang="EN-US">10<sup>-7</sup> M, the concentration of each of both the drugs was varied by keeping the other constant, and achieved lower detection limit of 3.25 nM for AMP and 1.16 nM for MCP. The developed method was found to be selective and rapid for the simultaneous determination of AMP and MCP. The proposed method was applied simultaneously in real samples and pharmaceutical samples, with satisfactory results.</span></p>

Differential Pulse Voltammetry Method for the Determination of Glucose on Multi-Nanostructured Active Electrode Modified by Platinum Nanoparticles

2012 ◽  
Vol 554-556 ◽  
pp. 440-444
Author(s):  
He Zhen Wu ◽  
Aie Cao ◽  
Di Lou Xu ◽  
Dao Bao Chu
Keyword(s):  
Differential Pulse Voltammetry ◽  
Platinum Nanoparticles ◽  
Glucose Concentration ◽  
Differential Pulse ◽  
Oxidation Peak ◽  
Active Electrode ◽  
Peak Current ◽  
Oxidation Peak Current ◽  
Pulse Voltammetry

Electrocatalytic oxidation of multi-nanostructured active electrode modified by platinum nanoparticles on glucose was examined. Based on 0.5mol/L KOH solution, we see a sensitive and good-shaped oxidation peak current near -0.77V (VS, SCE) by using differential pulse voltammetry method to scan in the range of -0.9~0.4V.The peak is regarded as the quantitative peak. There is a good linear relationship between glucose concentration and the peak current in the range of 1.0×10-2~1.0×10-5 mol/L. The linear correlation coefficient is 0.99864.The detection limit is 1.0×10-6mol/L. If added 0.06 m mol/L ascorbic acid or 0.3m mol/L uric acid (simulating human blood components), the determination of glucose is not interfered with. Results of the determination of glucose concentration in the blood are satisfactory.

Sensitive Electrochemical Monitoring of Piroxicam in Pharmaceuticals Using Carbon Ionic Liquid Electrode

2018 ◽  
Vol 15 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Ghazal Ghobadpour ◽  
Fatemeh Farjami ◽  
Farshid Fasihi
Keyword(s):  
Ionic Liquid ◽  
Differential Pulse ◽  
Carbon Ionic Liquid Electrode ◽  
Oxidation Peak ◽  
Analytical Technique ◽  
Liquid Electrode ◽  
Anodic Peak Current ◽  
Pulse Voltammetry ◽  
Electrochemical Monitoring

Background: Piroxicam is a non-steroidal anti-inflammatory drug. The prevailing clinical use and investigation of piroxicam necessitate a rapid and sensitive method for its determination. A carbon ionic liquid electrode, fabricated using graphite and the ionic liquid 1-octylpyridinium hexafluorophosphate (OPFP) was used as an electrochemical sensor for piroxicam determination. Methods: The surface of the proposed electrode was characterized by scanning electron microscopy. Cyclic voltammetry (CV) was applied to study the oxidation of piroxicam and to acquire information about the reaction mechanism. Differential pulse voltammetry was also used as an analytical technique for quantification of the sub-micromolar concentration of piroxicam. Results: One oxidation peak at 0.55V was observed at CILE. The oxidation peak at the CPE was weak, while the response was notably increased at the CILE. The proposed electrode exhibited interesting sensitivity towards the determination of piroxicam and the anodic peak current versus piroxicam concentration was linear in the ranges of 0.2-60 µM. The detection limit of 40 nM was achieved. Conclusion: The electroxidation process was irreversible and revealed adsorption controlled behavior. The method was successfully applied for the determination of piroxicam content in pharmaceutical samples.

scholarly journals Differentiation between phenol- and amino-substances in voltammetry determination of synthetic antioxidants in oils

2010 ◽  
Vol 8 (3) ◽  
pp. 607-616 ◽  
Author(s):  
Jaromíra Chýlková ◽  
Renáta Šelešovská ◽  
Jaroslava Machalíková ◽  
Libor Dušek
Keyword(s):  
Differential Pulse Voltammetry ◽  
Aromatic Amines ◽  
Supporting Electrolyte ◽  
Differential Pulse ◽  
Phenolic Antioxidants ◽  
Potential Range ◽  
Experimental Conditions ◽  
Lubricating Oils ◽  
Pulse Voltammetry

AbstractThe paper describes a method of voltammetric determination of antioxidants in lubricating oils developed with the use of Linear Sweep Voltammetry (LSV) and Fast Scan Differential Pulse Voltammetry (FSDPV). Experimental conditions have been found for simultaneous determination of phenol-based antioxidants and amino-antioxidants: the phenols can be electrochemically oxidized using the polarisation of gold disc electrode (AuDE) in the potential range of 0–1400 mV in 0.2 M H2SO4 in the presence of ethanol and acetonitrile at the ratio of 3:1. Secondary aromatic amines can be determined directly in this supporting electrolyte; the presence of phenolic antioxidants does not interfere with this analysis. On the other hand, secondary aromatic amines interfere with the determination of phenolic substances; therefore, the amines present have to be eliminated in a suitable way. A procedure for masking the aromatic amines using their reaction with nitrous acid has been suggested and optimised. The nitrosamines thus formed can be used for sensitive and selective determination of amino-antioxidants by means of cathodic reduction on the hanging mercury drop electrode (HMDE) using Fast Scan Differential Pulse Voltammetry. The method was applied in analysis of real samples of lubricating oils.

scholarly journals Simultaneous electrochemical determination of acetaminophen and metoclopramide at electrochemically pre-treated disposable graphite pencil electrode

2016 ◽  
Vol 6 (3) ◽  
pp. 265
Author(s):  
Shreekant M Patil ◽  
Vijay P Pattar ◽  
Sharanappa T Nandibewoor
Keyword(s):  
Simultaneous Determination ◽  
Differential Pulse ◽  
Electrochemical Determination ◽  
Experimental Conditions ◽  
Positive Direction ◽  
Oxidation Potentials ◽  
Voltammetric Behavior ◽  
Pulse Voltammetry ◽  
Apparent Shift

<p class="PaperAbstract"><span lang="EN-US">A sensitive and economic voltammetric method was developed for the simultaneous determination of acetaminophen (AMP) and metoclopramide (MCP) using pre-treated graphite pencil electrode (PTGPE). Compared to a graphite pencil electrode, the pre-treated electrode showed an apparent shift of the oxidation potentials in the positive direction and a notable enhancement in the current responses for both AMP and MCP. Cyclic voltammetry (CV) was used to study the voltammetric behavior of the drugs, while differential pulse voltammetry (DPV) was used to determine AMP and MCP simulta­neously. The dependence of the current on scan rate, pH and concentration was investi­gated to boost the experimental conditions for simultaneous determination. The calibra­tion curves were obtained over the range of 0.1</span><span lang="EN-US">×</span><span lang="EN-US">10<sup>-7</sup> to 1.1</span><span lang="EN-US">×</span><span lang="EN-US">10<sup>-7</sup> M, the concentration of each of both the drugs was varied by keeping the other constant, and achieved lower detection limit of 3.25 nM for AMP and 1.16 nM for MCP. The developed method was found to be selective, and rapid for the simultaneous determination of AMP and MCP. The proposed method was applied simultaneously in real samples and pharmaceutical samples, with satisfactory results.</span></p>

scholarly journals Electrochemical Behavior and Determination of Chlorogenic Acid Based on Carbon Nanotubes Modified Screen-Printed Electrode

2016 ◽  
Author(s):  
Xiao-Yan Ma ◽  
Hong-Qiao Yang ◽  
Hua-Bing Xiong ◽  
Xiao-Fen Li ◽  
Jing-Ting Gao ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Differential Pulse ◽  
Electrochemical Determination ◽  
Optimal Conditions ◽  
Linear Regression Equation ◽  
Screen Printed Electrode ◽  
Redox Peak ◽  
Pulse Voltammetry ◽  
Screen Printed

In this paper, carbon nanotubes modified screen-printed electrode (CNTs/SPE) was prepared and the CNTs/SPE was employed for the electrochemical determination of antioxidant substance Chlorogenic acids (CGAs). A pair of well-defined redox peak of CGA was observed at the CNTs/SPE in 0.10 mol∙L-1 acetic acid-sodium acetate buffer (pH 6.2) and electrode process is adsorption-controlled. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) method for the determination of CGA were proposed based on the CNTs/SPE. Under the optimal conditions, the proposed method exhibited linear ranges from 4.73&times;10-7 to 4.45&times;10-5 mol∙L-1, the linear regression equation was Ipa(&micro;A) = 4.1993 C (mol∙L-1)+1.1039 (r = 0.9976) and the detection limit for CGA could reach 3.25&times;10-6 mol∙L-1. The recovery of matrine was 94.74~106.65% (RSD = 2.92%) in coffe beans. The proposed method is quick, sensitive, reliable, and can be used for the determination of CGA.

Highly Sensitive Chitosan and ZrO2 Nanoparticles-Based Electrochemical Sensor for 8-Hydroxy-2’-deoxyguanosine Determination

2019 ◽  
Vol 15 (6) ◽  
pp. 648-655 ◽  
Author(s):  
Shengzhong Rong ◽  
Deng Pan ◽  
Xuehui Li ◽  
Mucong Gao ◽  
Hongwei Yu ◽  
...  
Keyword(s):  
Electrochemical Sensor ◽  
Differential Pulse Voltammetry ◽  
High Performance ◽  
Differential Pulse ◽  
Redox Activity ◽  
Zro2 Nanoparticles ◽  
Urine Specimen ◽  
Experimental Conditions ◽  
Pulse Voltammetry

Background: 8-Hydroxy-2’-deoxyguanosine (8-OHdG) has been regarded as a typical stable biomarker of DNA oxidative damage, and its level is one of the criteria for early diagnosis of various diseases. Considering the significance of 8-OhdG, various analytical techniques have been used for assaying 8-OHdG but all of them suffer from basic limitations like highly expensive instrumentation, large amount of sample requirement, complicated sample pre-treatment, tedious and time-consuming procedures etc. However, electroanalytical sensors provide a faster, easy and sensitive means of analyzing. Methods: The chitosan (CS) film provided the high electrode activity and stability which is required for detecting 8-OHdG though direct electrochemical oxidation. Zirconia was employed because it has some unique properties, such as high redox activity and selectivity etc. High-performance composite was easily detected by differential pulse voltammetry at a working voltage of 0. 51 V (vs. Ag/AgCl). A rapid and sensitive electrochemical sensor based on CS and metal oxide nanocrystalline for the determination of 8-OHdG was established. Results: Under optimized experimental conditions, the peak currents of differential pulse voltammetry increased as the concentrations of 8-OHdG increased from 10 to 200 ng·mL-1. The detection limit was 3.67 ng·mL-1 which was calculated by the S/N ratio of 3. The recoveries of the real spiked samples are in the range between 93.2 to 105.3%. Conclusion: The electrochemical sensor for direct 8-OHdG determination using a new CS/zirconia composite for GCE modification was developed and showed excellent reproducibility, stability and sensitivity for the specific determination of 8-OHdG in real urine specimen.

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