scholarly journals Voltammetric study of the interaction between oxacillin sodium and cysteine in the presence and absence of Mn(II)ions in neutral buffer solution

2007 ◽  
Vol 72 (10) ◽  
pp. 1003-1013 ◽  
Author(s):  
Ender Biçer ◽  
Emine Coşkun
Keyword(s):  
Square Wave Voltammetry ◽  
Catalytic Reduction ◽  
Mercury Electrode ◽  
Reduction Peak ◽  
Peak Potential ◽  
Buffer Solution ◽  
Voltammetric Study ◽  
Wave Voltammetry ◽  
Two Peaks ◽  
Reduction Peak Potential

In this study, the voltammetric behaviour of the interaction of oxacillin sodium (OXA) and OXA-cysteine (RSH) was studied by square-wave voltammetry, cyclic voltammetry in Britton-Robinson (B-R) buffer (pH 7.0). OXA gave two peaks at -0.248 and -1.224 V. For the interaction, the peak of mercurous cysteine thiolate (Hg2(SR)2) was selected. It was found that the peak currents corresponding to Hg2(SR)2 significantly decreased, while the peak potential shifted to more positive potentials upon the addition of OXA. The observed phenomena are due to the interaction of OXA with RSH on the surface of the mercury electrode. When OXA was added to the electrochemical cell along with Mn(II), new peaks at -0.146 and -0.608 V were observed. These peaks were due to the catalytic activity of OXA on the reduction of Mn(II) and could be attributed to the formation of Mn(II) complexes with different metal/ligand ratios. On the other hand, in the presence of RSH, the peak at -0.608 V vanished and a reduction peak was observed at -0.662 V. The catalytic reduction peak potential of Mn(II) at -0.662 V indicated that RSH slightly prevented the catalysis process of OXA due to their mutual interaction. .

Voltammetry of resazurin at a mercury electrode

2010 ◽  
Vol 64 (3) ◽  
Author(s):  
Semiha Çakir ◽  
Emine Arslan
Keyword(s):  
Square Wave Voltammetry ◽  
Mercury Electrode ◽  
Stripping Voltammetry ◽  
Cathodic Reduction ◽  
Reduction Peak ◽  
Square Wave ◽  
Wave Voltammetry ◽  
Reduction Mechanisms ◽  
Electrochemical Parameters ◽  
Catalytic Hydrogen

AbstractElectrochemical behavior of resazurin on HMDE in Britton-Robinson (B-R) buffers (pH 2.0–10.0) was studied using the square-wave voltammetry (SWV), square-wave adsorptive stripping voltammetry (SWAdSV), and cyclic voltammetry (CV) techniques. The voltammogram of resazurin in B-R buffer at pH < 4.0 exhibited two cathodic reduction peaks. The voltammetric peaks were obtained at −0.144 V (reversible) and −1.250 V (irreversible) at pH 3.2, and correspond to the reduction of resorufin to dihydroresorufin and to the catalytic hydrogen wave, respectively. At pH > 4.0, a new irreversible cathodic reduction peak, assigned to the protonation of N-oxide on the phenoxazin ring, was observed. Electrochemical parameters (I p/E p, I p/v, I p/pH, I p/t acc) of the compound were determined. From the voltammetric data, electrochemical reduction mechanisms for all peaks have been suggested. Maximum peak current for the reversible peak was obtained at pH 4.1. A linear relationship between the current and concentration was determined, and also the lowest detection limit was found as 3.25 × 10−8 mol L−1 and 1.98 × 10−10 mol L−1 for SWV and SWAdSV, respectively.

scholarly journals Polarographic determination of DNA based on its interaction with the phenanthroline-zinc(II) complex

2015 ◽  
Vol 80 (1) ◽  
pp. 87-96
Author(s):  
Ni Hui ◽  
Aiqin Liang ◽  
Changhui Xue ◽  
Wei Sun
Keyword(s):  
Reduction Peak ◽  
Determination Limit ◽  
Peak Potential ◽  
Buffer Solution ◽  
Peak Current ◽  
Reduction Peak Current ◽  
Relative Standard ◽  
Reduction Peak Potential ◽  
Voltammetric Technique

By using the linear sweep voltammetric technique, a phenanthroline (Phen) and zinc(II) (Phen-Zn(II)) complex was used as the electrochemical probe for the determination of double-stranded (ds) DNA. In pH 9.0 Britton- -Robinson (B-R) buffer solution, Phen can interact with Zn(II) to form a stable electroactive [Phen-Zn(II)] complex, which had a sensitive second order derivative polarographic reductive peak at -1.300 V (vs. SCE). After the addition of dsDNA into a solution of Phen-Zn(II) complex, the reduction peak current decreased with a negative shift of the reduction peak potential and without the appearance of new peaks. The results showed that a new supramolecular complex was formed via interaction of the Phen-Zn(II) complex with dsDNA. The conditions of interaction and the electrochemical detection were carefully investigated. Under the optimum conditions, the decrease in the reduction peak current was directly proportional to the dsDNA concentration in the range of 0.4-18.0 mg L-1 with the linear regression equation: ?Ip?/nA = 349.48 + + 84.647(c/mg L-1) (n = 13, ? = 0.991) and a determination limit of 0.20 mg L-1 (3?). The relative standard deviation (RSD) for 10 parallel determinations of 10.0 mg L-1 dsDNA was found to be 2.03 %. The method was successfully applied to the detection of synthetic samples with satisfactory results.

Cyclic single drop square wave polarography at spherical electrodes — the reversible case

1987 ◽  
Vol 65 (5) ◽  
pp. 1025-1032 ◽  
Author(s):  
Louis Ramaley ◽  
Wee Tee Tan
Keyword(s):  
Experimental Data ◽  
Square Wave Voltammetry ◽  
Simple Theory ◽  
Forward Peak ◽  
Single Drop ◽  
Peak Potential ◽  
Square Wave ◽  
Wave Voltammetry ◽  
Plane Theory ◽  
Best Fit

The influence of electrode sphericity and the results of sweep reversal are examined for square wave voltammetry and the square wave polarography in which an entire polarogram is obtained on a single drop. An expanding sphere treatment obtained by adding a spherical correction to expanding plane theory gives the best fit to the experimental data. Amalgam forming reactions fit the simple theory developed to a lesser extent than other reactions, especially on the reverse sweep. The shape of the differential polarogram is not significantly affected by sphericity and the reverse peak potential is approximately equal to the forward peak potential. Small differences in these potentials are due to the distortion of the square wave by the stairstep used for the sweep and the distortion of the polarogram due to drop growth. The ratio of the forward and reverse peak currents depends on the phasing of the square wave and stairstep in all cases and on other parameters for a growing drop.

Molecular and statistical modeling of reduction peak potential and lipophilicity of platinum(IV) complexes

2010 ◽  
Vol 16 (3) ◽  
pp. 361-372 ◽  
Author(s):  
James A. Platts ◽  
Giuseppe Ermondi ◽  
Giulia Caron ◽  
Mauro Ravera ◽  
Elisabetta Gabano ◽  
...  
Keyword(s):  
Statistical Modeling ◽  
Reduction Peak ◽  
Peak Potential ◽  
Reduction Peak Potential

scholarly journals Quantitative determination of glycyrrhizinic acid by square-wave voltammetry and high-pressure liquid chromatography

2003 ◽  
Vol 48 ◽  
pp. 3-8
Author(s):  
Aneta Dimitrovska ◽  
Valentin Mircevski ◽  
Svetlana Kulevanova
Keyword(s):  
High Pressure ◽  
Quantitative Determination ◽  
Electrode Surface ◽  
Square Wave Voltammetry ◽  
Mercury Electrode ◽  
Voltammetric Method ◽  
Square Wave ◽  
Glycyrrhizinic Acid ◽  
Wave Voltammetry

Novel adsorptive stripping square-wave voltammetric method as well as a new high-pressure liquid chromatographic method for direct determination of glycyrrhizinic acid in dosage pharmaceutical preparation, used against virus infections, have been developed. Glycyrrhizinic acid is an electrochemically active compound, which undergoes irreversible reduction on a mercury electrode surface in an aqueous medium. Its redox properties were studied thoroughly by means of square-wave voltammetry, as one of the most advanced electroanalytical technique. The voltammetric response depends mainly on the pH of the medium, composition of the supporting electrolyte, as well as the parameters of the excitement signal. It was also observed that the voltammetric properties strongly depend on the accumulation time and potential, revealing significant adsorption of glycyrrhizinic acid onto the mercury electrode surface. Upon this feature, an adsorptive stripping voltammetric method for quantitative determination of glycyrrhizinic acid was developed. A simple, sensitive and precise reversed phase HPLC method with photodiode array UV detection has also been developed, mainly for comparison and conformation of the results obtained with the voltammetric method.

Electrochemical studies of ganciclovir as the adsorbed catalyst on mercury electrode

2009 ◽  
Vol 74 (10) ◽  
pp. 1455-1466 ◽  
Author(s):  
Sławomira Skrzypek ◽  
Agnieszka Nosal-Wiercińska ◽  
Witold Ciesielski
Keyword(s):  
Square Wave Voltammetry ◽  
Mercury Electrode ◽  
Antiviral Drug ◽  
Linear Sweep Voltammetry ◽  
Protonated Form ◽  
Catalytic Method ◽  
Square Wave ◽  
Mercury Surface ◽  
Capacity Curves ◽  
Wave Voltammetry

Although ganciclovir (gan) as a purine analogue is a compound of biological interest (antiviral drug), it has been rarely electrochemically studied. In this paper surface catalytic electrode mechanism based on the hydrogen evolution reaction is analyzed under conditions of square-wave voltammetry and differential capacity curves of double layer measurements. The electrode mechanism is assumed to involve a preceding chemical reaction in which the adsorbed catalyst (ganads) is protonated at the electrode surface, i.e., ganads + H+aq → ganH+ads. The protonated form of the catalyst (ganH+ads) is irreversibly reduced at potential about –1.35 V vs Ag|AgCl, yielding the initial form of the catalyst and atomic hydrogen, i.e., ganH+ads + e → ganads + Haq. Changes of zero charge potential and surface tension point to the adsorption of ganciclovir molecule directed with guanine group to the mercury surface and suggests that ganciclovir molecules are not placed flat on the mercury surface. The effect of adsorption on mercury electrode was studied in detail in respect to analytical usefulness of the obtained results. A new catalytic method for voltammetric determination of ganciclovir was developed. The detection and quantification limits were 1.3 × 10–7 and 4.3 × 10–7 mol l–1 for square-wave voltammetry, and 1.4 × 10–7 and 4.7 × 10–7 mol l–1 for linear-sweep voltammetry.

scholarly journals Interaction study of moxifloxacin with Cu(II) ion using square-wave voltammetry and its application in the determination in tablets

2006 ◽  
Vol 31 (1) ◽  
pp. 31-38 ◽  
Author(s):  
M. A. G. Trindade ◽  
P. A. C. Cunha ◽  
T. A. de Araújo ◽  
G. M. da Silva ◽  
V. S. Ferreira
Keyword(s):  
Square Wave Voltammetry ◽  
Reduction Peak ◽  
Interaction Study ◽  
Accumulation Time ◽  
Square Wave ◽  
Wave Voltammetry ◽  
Electroanalytical Method ◽  
Limit Detection ◽  
Good Agreement

This work presents an electroanalytical method for the determination of moxifloxacin (MOXI) in tablets by its interaction with Cu(II) ion and subsequent electrochemical reduction at hanging mercury drop electrode (HMDE). A well-defined reduction peak at -0.21 V vs. Ag/AgCl in Phosphate buffer 0.04 mol L-1 pH 8.0 was observed for the complex reduction MOXI-Cu(II), using square-wave voltammetry (SWV). Using a 10 s of accumulation time at -0.40 V was found a limit detection of 3.60x10-8 mol l-1. The obtained results have shown good agreement with those obtained by spectrophotometric method.

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