scholarly journals Voltammetric determination of imidacloprid and thiamethoxam

2005 ◽  
Vol 70 (5) ◽  
pp. 735-743 ◽  
Author(s):  
Valeria Guzsvány ◽  
Ferenc Gaál ◽  
Luka Bjelica ◽  
Silvija Ökrész
Keyword(s):  
Glassy Carbon ◽  
Electrode Surface ◽  
Limit Of Detection ◽  
Voltammetric Determination ◽  
Polarization Mode ◽  
Voltammetric Method ◽  
Surface Pretreatment ◽  
Working Electrode ◽  
Limit Of Quantitation

A simple voltammetric method using a glassy carbon working electrode was developed for the determination of two members from the neonicotinoid group of insecticides: imidacloprid and thiamethoxam. The experiments showed that the voltammetric response depends on the mode of electrode surface pretreatment and the polarization mode. The response appeared to be linear in the range from 0.028 to 0.50 mg/cm3 for both analyses. The limit of detection was 0.0077 mg/cm3 for imidacloprid and 0.0085 mg/cm3 for thiamethoxam, the limit of quantitation was 0.026 mg/cm3 and 0.028 mg/cm3, respectively. The developed method was applied for the determination of these insecticides in potato samples sprayed with Confidor 200-SL or Actara 25-WG as well as commercial formulations of imidacloprid and thiamethoxam. A recovery trial was performed to assess the accuracy of the results, the recovery values being between 95?102 % for both of neonicotinoids.

scholarly journals Microfabricated Au-Film Sensors for the Voltammetric Determination of Hg(II)

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 1518
Author(s):  
Maria Tsetsoni ◽  
Eleni Roditi ◽  
Christos Kokkinos ◽  
Anastasios Economou
Keyword(s):  
Electrode Surface ◽  
Limit Of Detection ◽  
Anodic Stripping Voltammetry ◽  
Stripping Voltammetry ◽  
Voltammetric Determination ◽  
Film Sensor ◽  
Au Film ◽  
Working Electrode ◽  
Anodic Stripping

In this work, a microfabricated Au-film sensor was designed and fabricated for thevoltammmetric determination of Hg(II). The electrode was fabricated on a silicon chip with astandard microengineering approach utilizing photolithography for patterning the electrode shapeand sputtering for deposition of thin Cr and Au films on the surface of the sensors. The sensorswere used for the determination of trace Hg(II) with anodic stripping voltammetry (ASV): initiallyHg(II) in the sample was accumulated on the Au working electrode surface by reduction andformation of an Au(Hg) amalgam followed by oxidation of the preconcentrated metallic Hg using asquare wave voltammetric scan. The limit of detection was 1.5μgL−1 and the coefficient of variationof 10 consecutive measurements was 3.1%.

scholarly journals Direct chronopotentiometric analysis of riboflavin using a glassy carbon vessel as the working electrode

2016 ◽  
pp. 143-151
Author(s):  
Tanja Brezo ◽  
Zorica Stojanovic ◽  
Zvonimir Suturovic ◽  
Snezana Kravic ◽  
Jovana Kos ◽  
...  
Keyword(s):  
Glassy Carbon ◽  
Limit Of Detection ◽  
Supporting Electrolyte ◽  
Relative Sensitivity ◽  
Working Electrode ◽  
Limit Of Quantitation ◽  
Experimental Parameters ◽  
Hplc Analyses ◽  
Process Vessel

A new method for the determination of riboflavin (vitamin B2) was developed based on chronopotentiometry with a glassy carbon process vessel macroelectrode. The method optimisation included investigation of the most important experimental parameters: type and concentration of the supporting electrolyte, initial potential, reduction current, and the working electrode surface area. The reduction signal of riboflavin appeared at about -0.12 V vs. Ag/AgCl (3.5 mol/dm3 KCl) electrode in 0.025 mol/dm3 HCl as the supporting electrolyte. A linear response was obtained in the the range of 0.05-4 mg/dm3. The limit of detection and limit of quantitation were 0.018 mg/dm3 and 0.054 mg/dm3, respectively. Due to the use of specific working electrode, a significant enhancement of the method relative sensitivity of about 10 times was achieved. The accuracy of the defined method was confirmed by HPLC analyses. The developed method was successfully applied for the quantitation of riboflavin in various pharmaceutical multivitamin preparations.

Voltammetry Determination of Cefotaxime on Zinc Oxide Nanorod Modified Electrode

2020 ◽  
Vol 17 (1) ◽  
pp. 40-46
Author(s):  
Vanitha Vasantharaghavan ◽  
Ravichandran Cingaram
Keyword(s):  
Zinc Oxide ◽  
Glassy Carbon Electrode ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Accurate Determination ◽  
Voltammetric Determination ◽  
Carbon Electrode

Background: The Glassy Carbon Electrode (GCE) was modified with zinc oxide nanoparticles to enhance the electrocatalytic activity of the redox behavior of cefotaxime ion. ATOMIC Force Microscopy (AFM) photographic studies showed the nanorod like structure of the zinc oxide, which was coated uniformly on the electrode surface. Methods: The zinc oxide nanorod modified electrode was used as novel voltammetric determination of cefotaxime. The results of voltammetric behavior are satisfactory in the electro oxidation of cefotaxime, and exhibit considerable improvement compared to glassy carbon electrode. Results: Under the optimized experimental conditions, the ZnO nanorod modified electrode exhibit better linear dynamic range from 300 ppb to 700 ppb with lower limit of detection 200 ppb for the stripping voltammetric determination of cefotaxime. Conclusion: The pharmaceutical and clinical formulation of cefotaxime was successfully applied for accurate determination of trace amounts on ZnO nanomateials modified electrode.

Voltammetric determination of cobalt (II) using a glassy carbon working electrode

1981 ◽  
Vol 309 (5) ◽  
pp. 397-398 ◽  
Author(s):  
M. Čakrt ◽  
J. Berčík ◽  
Z. Hladký ◽  
A. Mathiasová
Keyword(s):  
Glassy Carbon ◽  
Voltammetric Determination ◽  
Working Electrode

scholarly journals Voltammetric Determination of Pd(II) Using 5-Hydroxyimino-4-imino-1,3-thiazolidin-2-one after a Thermal Activation of the Interaction

2021 ◽  
Vol 15 (3) ◽  
pp. 324-329
Author(s):  
Petro Rydchuk ◽  
◽  
Oksana Labyk ◽  
Lesya Oleksiv ◽  
Oleksandr Tymoshuk ◽  
...  
Keyword(s):  
Thermal Activation ◽  
Limit Of Detection ◽  
Supporting Electrolyte ◽  
Voltammetric Determination ◽  
Real Sample ◽  
Optimal Conditions ◽  
Voltammetric Method ◽  
The Real ◽  
Ph Range

The interaction of Pd(II) with 5-hydroxyimino-4-imino-1,3-thiazolidin-2-one (HITO) was investigated over the pH range of 1.0–10.0. Optimal conditions for the voltammetric determination of Pd(II) were established. A new voltammetric method of Pd(II) determination by the peak of complex using NaCl as a supporting electrolyte at pH 2.0 was developed with the limit of detection 2.0∙10-7 M. The study of the method’s selectivity was presented in the work. The correctness of the method was confirmed by the analysis of model solutions and the real sample (resistor SP5-35B).

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.

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