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.

Determination of Drimarene Blue X-BLN at a glassy carbon electrode by differential pulse voltammetry

2011 ◽  
Vol 76 (12) ◽  
pp. 1765-1773 ◽  
Author(s):  
Abd-Elgawad M. Radi ◽  
Mohammed R. Mostafa ◽  
Reda M. Elshafey ◽  
Talaat A. Hegazy
Keyword(s):  
Differential Pulse Voltammetry ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Supporting Electrolyte ◽  
Differential Pulse ◽  
Redox Couple ◽  
Carbon Electrode ◽  
Validation Parameters ◽  
Pulse Voltammetry

The electrochemical oxidation behaviour of Drimarene Blue X-BLN (DB) has been investigated in phosphate buffers (pH 2.54–10.18) by cyclic and differential pulse voltammetry (DPV) at a glassy carbon electrode (GCE). The oxidation of DB dye generated well-defined pH-dependent two pairs of quasi-reversible anodic-cathodic peak couples. DB exhibited the second redox couple over the entire pH range, while the first redox couple disappeared for pH ≥ 6.70. The redox processes were adsorption-controlled. An electroanalytical method was developed for the determination of DB in phosphate buffer solution (pH 2.85) as supporting electrolyte using DPV. The anodic current heights varied linearly with DB concentrations in the ranges 2 × 10–6–3 × 10–5 and 6 × 10–6–3 × 10–5 mol l–1 with limits of detection (LOD) of 8.7 × 10–7 and 5.7 × 10–7 mol l–1 and limits of quantification (LOQ) of 2.9 × 10–6 and 1.9 × 10–6 mol l–1 for the first and second anodic peaks, respectively. Validation parameters, such as accuracy, precision and recovery were evaluated. The proposed method was successfully applied to the determination of DB in tap water and the analytical results compared well with those obtained by the spectrophotometric method.

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.

scholarly journals Direct and simultaneous determination of four phenolic antioxidants in biodiesel using differential pulse voltammetry assisted by artificial neural networks and variable selection by decision trees

Fuel ◽  
2019 ◽  
Vol 236 ◽  
pp. 803-810 ◽  
Author(s):  
Lívia de Souza Schaumlöffel ◽  
Jônathan William Vergani Dambros ◽  
Pedro Rafael Bolognese Fernandes ◽  
Mariliz Gutterres ◽  
Clarisse Maria Sartori Piatnicki
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Variable Selection ◽  
Differential Pulse Voltammetry ◽  
Decision Trees ◽  
Simultaneous Determination ◽  
Differential Pulse ◽  
Phenolic Antioxidants ◽  
Pulse Voltammetry

Polarographic and voltammetric determination of 6-mercaptopurine and 6-thioguanine

1986 ◽  
Vol 51 (11) ◽  
pp. 2466-2472 ◽  
Author(s):  
Jiří Barek ◽  
Antonín Berka ◽  
Ludmila Dempírová ◽  
Jiří Zima
Keyword(s):  
Detection Limit ◽  
Differential Pulse Voltammetry ◽  
Detection Limits ◽  
Differential Pulse ◽  
Voltammetric Determination ◽  
Differential Pulse Polarography ◽  
Hanging Mercury Drop Electrode ◽  
Pulse Polarography ◽  
Pulse Voltammetry

Conditions were found for the determination of 6-mercaptopurine (I) and 6-thioguanine (II) by TAST polarography, differential pulse polarography and fast-scan differential pulse voltammetry at a hanging mercury drop electrode. The detection limits were 10-6, 8 . 10-8, and 6 . 10-8 mol l-1, respectively. A further lowering of the detection limit to 2 . 10-8 mol l-1 was attained by preliminary accumulation of the determined substances at the surface of a hanging mercury drop.

The voltammetric determination of 4-nitrobiphenyl

1991 ◽  
Vol 56 (3) ◽  
pp. 595-601 ◽  
Author(s):  
Jiří Barek ◽  
Gulamustafa Malik ◽  
Jiří Zima
Keyword(s):  
Differential Pulse Voltammetry ◽  
Differential Pulse ◽  
Voltammetric Determination ◽  
Hanging Mercury Drop Electrode ◽  
Optimum Conditions ◽  
Mercury Drop Electrode ◽  
Working Electrode ◽  
Pulse Voltammetry ◽  
Unstirred Solution

Optimum conditions were found for the determination of 4-nitrobiphenyl by fast scan differential pulse voltammetry at a hanging mercury drop electrode in the concentration range 1 . 10-5 to 2 . 10-7 mol l-1. A further increase in sensitivity was attained by adsorptive accumulation of this substance on the surface of the working electrode, permitting determination in the concentration range (2 – 10) . 10-8 mol l-1 with one minute accumulation of the substance in unstirred solution or (2 – 10) . 10-9 mol l-1 with three-minute accumulation in stirred solution. Linear scan voltammetry can be used to determine 4-nitrobiphenyl in the concentration range (2 – 10) . 10-9 mol l-1 with five-minute accumulation in stirred solution, with the advantage of a smoother baseline and smaller interference from substances that yield only tensametric peaks.

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...

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