ABSTRACT
Cyclic Voltammetry reveals the reversible electrode processes during the cyclic oxidation-reduction of the colchicine in 0.1 M H2SO4. The behaviour of Peak potential with pH was studied to investigate the acid base reaction of the species, involved in the electrochemical reaction.
ABSTRACT
The rate constants for the reaction between dibromosuccinate and hydroxide ions have been determined in the presence of lithium and sodium chloride. Effects of temperatures and added electrolytes on this reaction have also been examined. It has been found that smaller radii have less accelerating effects on the rate of reaction. The activation parameters such as apparent energy of activation (Ea), change in enthalpy of activation (DeltaH#), change in entropy of activation (DeltaS#) and change in free energy of activation (DeltaG#) have been calculated in the absence and presence of lithium and sodium chloride for the reaction and discussed.
ABSTRACT
Anodic Voltammetry of ascorbic acid at platinum and gold rotating disc electrodes has been examined in acidic and alkaline media. Ascorbic acid is oxidised by a single two electron wave at platinum and one electron two step at gold electrode. The best medium for electroanalysis is 0.1 mol 1(-1) sulphuric acid in which it shows obedience to the Levich relationship at both electrodes. The limiting current is linearly proportional to ascorbic acid concentration with Zero intercept and shows excellent rapid voltammetric determination. Electrode Kinetic parameters for mass and charge transfer have been determined. Voltammetric method has been used to determine the number of electrons involved in the reaction and the reaction mechanism has been elucidated.
Subject(s)
Gold , Platinum , Acids , Ascorbic Acid , Electrochemistry , ElectrodesABSTRACT
The interaction of anionic surface active agents e.g. sodium decyl sulphate (SDS), sodium dodecyl sulphate (SDDS), sodium tetradecyl sulphate (STDS), sodium hexadecyl sulphate (DHDS) and sodium octadecyl sulphate (DODS) with cationic dyes, methylene blue (MB), crystal violet (CV) acridine orange (AO), rhodamine 6G (Rh 6G) and quinacrine dihydrochloride (QD) has been studied in three regions by conductometric titration. In the first region ion pair association occurs and the species (cationic and anionic) exist in equilibrium with homogeneous solution. In the second region complexation occurs by 1:1 with MB, CV and AO and by 2:1 with QD and Rh 6G forming a heterogeneousphase, separation and equilibration containing free ions and ion-pair. In the third region the micelle formation occurs by the excess of anions in the presence of cations as well as ion-pair formation and separated complex ions that give solubilization of the complex to a homogeneous clear solution.
ABSTRACT
Norgaman has been examined by anodic rotating disc electrode voltammetry in buffered media over the range of pH from 0-11.5. The best medium is 0.1 mol 1(-1) sulphuric acid in which the anodic wave is well defined at lower rotation speeds. The compound does not show obedience to the Levich relationship at platinum and gold electrodes. Rapid determination of the compound is not possible due to the adsorption of the oxidation product. Electrode mechanism for the reaction has been elucidated.
ABSTRACT
Cyclic voltammetric technique has been used to determine the electrochemical adsorption behaviour of riboflavin at platinum disc electrode in acidic solution. The electrode loses its activity after the first cyclic curve due to coating of its surface with the adsorbed species. The adsorption strength of riboflavin has been compared with some of the strongly adsorbed materials. This technique is employed to determine the amount of the species adsorbed on the surface of the electrode as the quantity of charge consumed is proportional to the area under the first cycle in the voltammogram.
ABSTRACT
The electroreduction of riboflavin (FMN) has been examined by cathodic rotating disc voltammetry in acidic and basic media at platinum and gold electrodes. It has proved to be diversely reducible best at gold electrode in the alkaline media. Rapid voltametric determination of the substance at gold electrode was effective and gave a mean standard deviation of 1%. Riboflavin at platinum electrode is cathodically active but the voltammograms do not obey the Levich relationship and adsorption destroys the electrode activity. The technique can be conveniently applied to the rapid determination of riboflavin in pure solution and in formulated products.
