Simple Real-time Voltammetric Method for Captopril Determination in Pharmaceutical Formulation

A novel voltammetric assay for captopril (CAP) determination by using an electrochemically pretreated pencil graphite electrode (PGE*) is presented. The electrochemical oxidation reaction of CAP was investigated with PGE* by using cyclic voltammetry and linear sweep voltammetry techniques. CAP was electrochemically inactive at the non-pretreated pencil graphite electrode surface, while a sharp anodic wave with an anodic peak potential at around 200 mV resulted by using the PGE*. According to kinetic studies upon the electrode behavior, a new reaction mechanism for electrochemical oxidation of captopril is proposed. The sensor was examined as a selective, simple and precise new electrochemical disposable electrode for the determination of CAP in pharmaceutical samples in complex medical cases associated with sleep apnea, with good results.

Electrochemical Synthesis of Ferrate Using Iron with 3.3% Si Anode

A ferrate solution about 236.87mM was obtained under the optimum conditions: 16MNaOH, J=100mAcm-2, 35°C, electrolysis duration (1h), The optimal current efficiency was 45.86%. The cyclic voltammogram of iron with 3.3% Si revealed a new anodic wave between -0.2V and 0.1V versus HgO/Hg corresponding to Fe(V) production.

Anodic reactions of sulphate in molten salts

Electrochemical behaviour of sulphate under anodic polarization in molten sodium chloride, cryolite and sodium fluoride was investigated by cyclic voltammetry and chronopotentiometry at the temperatures of 820°C, 1010°C, and 1000°C, respectively. Using a platinum working electrode, two waves were observed on the chronopotentiograms in the systems: NaCl-Na2SO4 and Na3AlF6-Na2SO4. The first wave was attributed to the formation of oxygen. The second wave probably originated from the reaction of oxygen with platinum, or from oxidation of SO3 decomposition products. Three waves were observed for the anodic process of sulphate ions dissolved in molten sodium fluoride. The first wave was attributed to the formation of oxygen. The second and the third wave were attributed to the formation of PtO and PtO2. This conclusion was supported by cyclic voltammetry experiments of the in-situ formed sulphide in molten NaCl at 820°C and by chronopotentiometry on a gold working electrode in the system NaCl-Na2SO4, where no anodic wave was observed.

Electrochemical Oxidation of Probucol in Anhydrous Acetonitrile

Electrochemical oxidation of probucol in anhydrous acetonitrile was studied as a model of the metabolic oxidation of the substance. The study was performed by DC voltammetry, potentiostatic coulometry, cyclic voltammetry and preparative electrolysis. Probucol gives a single anodic wave E1/2 = 0.92 V. Cyclic voltammetry showes that its electrooxidation proceeds by formation of probucol radical. 2,6-Di-tert-butyl-4-(isopropylsulfanyl)phenol, 2,6-di-tert-butyl-4-sulfanylphenol, 2,6-di-tert-butyl-4-methylphenol and 2,6-di-tert-butylphenol were isolated as products of electrochemical oxidation.