Electroanalytical chemistry of vanadium complexes: Electrochemical oxidation of [V(IV)O(nta)(H2O)]-

1989 ◽  
Vol 54 (1) ◽  
pp. 64-69 ◽  
Author(s):  
Roland Meier ◽  
Gerhard Werner ◽  
Matthias Otto
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Oxidation ◽  
Ph Dependence ◽  
Differential Pulse ◽  
Nitrilotriacetic Acid ◽  
Reduced Form ◽  
Vanadium Complexes ◽  
Differential Pulse Polarography ◽  
Electroanalytical Chemistry ◽  
Ph Range

Electrochemical oxidation of [V(IV)O(nta)(H2O)]- (H3nta nitrilotriacetic acid) was studied in aqueous solution by means of cyclic voltammetry, differential pulse polarography, and current sampled DC polarography on mercury as electrode material. In the pH-range under study (5.5-9.0) the corresponding V(V) complex is produced by one-electron oxidation of the parent V(IV) species. The oxidation product is stable within the time scale of cyclic voltammetry. The evaluation of the pH-dependence of the half-wave potentials leads to a pKa value for [V(IV)O(nta)(H2O)]- which is in a good agreement with previous determinations. The measured value for E1/2 is very close to the formal potential E0 calculated via the Nernst equation on the basis of known literature values for log Kox and log Kred, the complex stability constants for the oxidized and reduced form, respectively.

scholarly journals Differential Pulse Polarographic Determination of Procymidone in Formulations and Wine

2002 ◽  
Vol 85 (3) ◽  
pp. 731-735 ◽  
Author(s):  
Neelam Y Sreedhar ◽  
Thommandru R Babu ◽  
Kethamreddy Samatha ◽  
Devarapalli Sujatha ◽  
Thenepalli Thriveni
Keyword(s):  
Reduction Process ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Experimental Conditions ◽  
Controlled Potential Electrolysis ◽  
Pulse Polarography ◽  
Half Wave ◽  
Single Well ◽  
Controlled Potential ◽  
Ph Range

Abstract The dicarboximide fungicide procymidone was studied systematically by using direct current polarography, cyclic voltammetry, differential pulse polarography (DPP), controlled potential electrolysis, and millicoulometry in the universal buffer medium with dimethylformamide as the solvent. Procymidone exhibited a single well-defined polarographic wave in the pH range 2.0–6.0, leading to the formation of the hydroxy compound. The overall reduction process was diffusion-controlled and adsorption-free. The variation of half-wave potential with pH, the concentration of the analyte, and other experimental conditions are described. The reduction mechanism proposed is an overall 4-electron process, in which the dicarboximide group is reduced. DPP was used to determine procymidone in agricultural formulations and wine at the optimum conditions found; a detection limit of 2.4 × 10−9M was estimated. The results obtained by the proposed method were also compared with those obtained by other methods.

scholarly journals Differential Pulse Polarographic Determination of Lead in Complex Materials after Adsorption of Its N-Methylethylxanthocarbamate Complex on Microcrystalline Naphthalene or on NMethylethylxanthocarbamate–Benzyldimethyltetradecylammonium–Naphthalene Adsorbent

2002 ◽  
Vol 85 (3) ◽  
pp. 712-718
Author(s):  
Mohammad Farid Hussain ◽  
Anil Kumar Sangahi ◽  
Iqbal Ahmad ◽  
Bal Krishan Puri
Keyword(s):  
Flow Rate ◽  
Signal To Noise Ratio ◽  
Differential Pulse ◽  
Correlation Factor ◽  
Differential Pulse Polarography ◽  
Pulse Polarography ◽  
Relative Standard ◽  
Ph Range ◽  
Microcrystalline Naphthalene

Abstract Lead is quantitatively adsorbed as the lead N-methylethylxanthocarbamate (MEXC)–benzyldimethyltetradecylammonium (BDTA) ion pair complex on microcrystalline naphthalene in the pH range 4.0–11.0. The metal is desorbed with HCl and determined by differential pulse polarography. Alternatively lead can be quantitatively adsorbed on the adsorbent (MEXC–BDTA–naphthalene) packed in a column at a flow rate of 1–2 mL/min and determined similarly. Dissolved oxygen is removed by adding a few milliliters of 4% NaBH4 solution. The detection limit is 0.12 μg/mL at the minimum instrumental settings (signal-to-noise ratio, 2). Linearity was obtained over the concentration range 0.3–20.0 μg/mL with a correlation factor of 0.9998 and a relative standard deviation of ± 0.98%. Various parameters, such as the effect of pH, volume of aqueous phase, flow rate, and the interference of a large number of metal ions and anions, were studied in detail to optimize the conditions for the trace determination of lead in various standard alloys, standard biological materials, and environmental samples.

scholarly journals Electrochemical Reduction Behaviour of Zileuton at a Dropping Mercury Electrode by Polarography

2010 ◽  
Vol 7 (1) ◽  
pp. 166-170 ◽  
Author(s):  
N. Y. Sreedhar ◽  
M. Sankara Nayak ◽  
K. Srinivasa Prasad ◽  
P. R. Prasad ◽  
C. Nageswar Reddy
Keyword(s):  
Electrochemical Behaviour ◽  
Mercury Electrode ◽  
Reference Electrode ◽  
Pharmaceutical Formulations ◽  
Differential Pulse ◽  
Forward Rate ◽  
Dimethyl Formamide ◽  
Differential Pulse Polarography ◽  
Dropping Mercury Electrode ◽  
Ph Range

Electrochemical behaviour of anticancer drug zileuton was investigated by direct current polarography (DCP) and differential pulse polarography using a dropping mercury electrode (DME) as working electrode and Ag/AgCl reference electrode in universal buffer of pH range from 2.0 to 12.0. The drug was extracted from the dosage forms in dimethyl formamide (DMF). Kinetic parameters such as diffusion co-efficient (D) and heterogeneous forward rate constants (k0f,h) are evaluated and reported. The differential pulse polarographic method has been developed for the determination of this drug in pharmaceutical formulations.

Electrochemical reduction of benzenediazonium salts in aprotic medium

1989 ◽  
Vol 54 (6) ◽  
pp. 1496-1507
Author(s):  
Pavel Janderka ◽  
Igor Cejpek
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Reduction ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Reduction Mechanism ◽  
Aprotic Medium ◽  
Pulse Polarography ◽  
Dc Polarography ◽  
Donor Numbers

DC polarography, TAST polarography, differential pulse polarography, polarography with superimposed alternating current, slow cyclic voltammetry with a hanging Hg drop electrode and a Pt electrode, rapid cyclic voltammetry with a hanging Hg drop, and coulometry were used to study the electrochemical reduction of p-methoxy- and p-nitrobenzenediazonium cations in aprotic medium. A reduction mechanism involving two separate one-electron steps is proposed, the first of which being complicated by adsorption and follow-up chemical reaction leading to evolution of nitrogen. The basicity of the aprotic solvents, expressed by donor numbers according to Gutman, influences the reduction mechanism of these cations.

scholarly journals Voltammetric Behavior of Zaleplon and Its Differential Pulse Polarographic Determination in Capsules

2005 ◽  
Vol 88 (4) ◽  
pp. 1135-1141 ◽  
Author(s):  
Gipsy Larenas ◽  
Soledad Bollo ◽  
Marcelo Rodriguez ◽  
Igor Lemus ◽  
Luis J Nuñez-Vergara ◽  
...  
Keyword(s):  
Column Liquid Chromatography ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Content Uniformity ◽  
Reduction Peak ◽  
Buffer Solution ◽  
Pulse Polarography ◽  
Voltammetric Behavior ◽  
Ph Range ◽  
The Individual

Abstract In this work both the electrochemical behavior and the analysis of the hypnotic pyrazolopyrimidine derivative zaleplon were studied. Zaleplon in ethanol–0.1M Britton Robinson buffer solution (30–70) showed 2 irreversible, well-defined cathodic responses in the pH range of 2–12 using differential pulse polarography (DPP), tast polarography, and cyclic voltammetry. From chronocoulometric studies, it was possible to conclude that one electron was transferred in each reduction peak or wave. For analytical purposes, the DPP technique working at pH 4.5 for peak I was selected, which exhibited adequate repeatability, reproducibility, and selectivity. The recovery was 99.97 ± 1.52%, and the detection and quantitation limits were 5.13 × 10−7M and 1.11 × 10−6M, respectively. The DPP method was applied successfully to the individual assay of capsules in order to verify the content uniformity of zaleplon. Treatment of the sample is not required because the excipients do not interfere, the method is not time consuming, and it is less expensive than column liquid chromatography.

scholarly journals The Electrochemical Oxidation of Hydroquinone and Catechol through a Novel Poly-geminal Dicationic Ionic Liquid (PGDIL)–TiO2 Composite Film Electrode

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1907
Author(s):  
Yanni Guo ◽  
Deliang He ◽  
Aomei Xie ◽  
Wei Qu ◽  
Yining Tang ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Ionic Liquid ◽  
Composite Film ◽  
Electrochemical Oxidation ◽  
Differential Pulse ◽  
Tio2 Electrode ◽  
Film Electrode ◽  
Au Electrode ◽  
Dicationic Ionic Liquid ◽  
Pulse Voltammetry

A novel poly-geminal dicationic ionic liquid (PGDIL)-TiO2/Au composite film electrode was successfully prepared by electrochemical polymerization of 1,4-bis(3-(m-aminobenzyl)imidazol-1-yl)butane bis(hexafluorinephosphate) containing polymerizable anilino groups in the electrolyte containing nano-TiO2. The basic properties of PGDIL–TiO2/Au composite films were studied by SEM, cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse voltammetry. The SEM results revealed that the PGDIL–TiO2 powder has a more uniform and smaller particle size than the PGDIL. The cyclic voltammetry results showed that the catalytic effect on electrochemical oxidation of hydroquinone and catechol of the PGDIL–TiO2 electrode is the best, yet the Rct of PGDIL–TiO2 electrode is higher than that of PGDIL and TiO2 electrode, which is caused by the synergistic effect between TiO2 and PGDIL. The PGDIL–TiO2/Au composite electrode presents a good enhancement effect on the reversible electrochemical oxidation of hydroquinone and catechol, and differential pulse voltammetry tests of the hydroquinone and catechol in a certain concentration range revealed that the PGDIL–TiO2/Au electrode enables a high sensitivity to the differentiation and detection of hydroquinone and catechol. Furthermore, the electrochemical catalytic mechanism of the PGDIL–TiO2/Au electrode was studied. It was found that the recombination of TiO2 improved the reversibility and activity of the PGDIL–TiO2/Au electrode for the electrocatalytic reaction of HQ and CC. The PGDIL–TiO2/Au electrode is also expected to be used for catalytic oxidation and detection of other organic pollutants containing –OH groups.

Electrochemical Behaviour of 3-Pyridyl-N,N-bis[(8-quinolyl)amino]methane

1993 ◽  
Vol 58 (6) ◽  
pp. 1279-1284
Author(s):  
Angeles Loeches ◽  
Carmen Teijeiro ◽  
Dolores Marín
Keyword(s):  
Cyclic Voltammetry ◽  
Limit Of Detection ◽  
Electrochemical Behaviour ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Reduction Mechanism ◽  
Pulse Polarography ◽  
Dc Polarography ◽  
The Waves

3-Pyridyl-N,N-bis[(8-quinolyl)amino]methane was studied by DC polarography, coulometry, cyclic voltammetry and differential pulse polarography in a system comprising Britton-Robinson buffer and 15 vol.% ethanol at pH 7.0. The nature of the waves was investigated, and the reduction mechanism is suggested. DPP was also used for a quantitative determination of the substance, and a limit of detection of 3 μmol l-1 was obtained.

Influence of substituents on electrochemical reduction potentials of benzenediazonium salts

1989 ◽  
Vol 54 (12) ◽  
pp. 3135-3143 ◽  
Author(s):  
Pavel Janderka ◽  
Igor Cejpek
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Reduction ◽  
Linear Correlation ◽  
Structural Parameters ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Reduction Potentials ◽  
Pulse Polarography ◽  
Substituent Constants ◽  
Influence Of Substituents

TAST polarography, differential pulse polarography, and cyclic voltammetry on a hanging mercury drop and on a platinum disc were employed to measure the electrochemical reduction potentials of nine para substituted benzenediazonium salts in dimethylformamide. A satisfactory linear correlation was obtained between the potentials of the adsorption prewave and the substituent constants σ+p. The influence of substituents on some structural parameters was studied by using the CNDO/2 method for both a closed and a opened shell.

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