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Convolutive, deconvolutive cyclic voltammetric, digital simulation, chronoamperometric, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used for clarifying the characterization of charge transfer complex (CT) of 4,4'-bipyridine with benzoquinone derivatives. These studies were achieved at a gold electrode in TBAPL/CH2Cl2. The kind of the electrode reaction and the kinetic parameters of the CT complex under study were calculated and explained via the above methods, then confirmed via digital simulation. SEM and TEM were performed for characterization of the structural morphology of the presented complex as well as showing the nanostructured of the complex. [ABSTRACT FROM AUTHOR]

Studies on magnetic anti dot nano-structures with three-dimensional (3D) architectures, fabricated using a self-assembly template method are presented. It is found that patterning transverse to the film plane, which is a unique feature of this method, results in novel magnetic behavior.

We present studies on magnetic anti-dot nano-structures with three-dimensional (3D) architectures, fabricated using a self-assembly template method. We find that patterning transverse to the film plane, which is a unique feature of this method, results in novel magnetic behavior. In particular, one of the key parameters for a magnetic material, the coercive field Bc, was found to demonstrate an oscillatory dependence on film thickness. [ABSTRACT FROM AUTHOR]

Electrochemical properties of nickel on a gold disk electrode from aqueous hexagonal lyotropic liquid crystalline phase in Brij 78 as supporting electrolyte through the electrochemical techniques of cyclic voltammetry (CV) and convolution -deconvolution voltammetry, coupled with method of digital simulation was investigated. Scan rate effect on the peak height and on the peak position was indicated. It was found that scanning the potential in the cathodic direction produced two peaks, corresponding to the reduction of Ni2+ to Ni metal. Also reversing the potential to the anodic direction was characterized by nickel dissolution. [ABSTRACT FROM AUTHOR]

The electrochemical studies of N, N - bis(pyrazinyl) - 3, 4, 9, 10 - perylene bis (dicarboximide) (PyPD) dye has been carried out on Pt electrode using cyclic voltammetry and convolution deconvolution voltammetry combined with digital simulation technique at a platinum electrode in 0.1 mol L-1 tetrabutylammonium perchlorate (TBAP) in acetonitrile solvent (CH3CN). The compound under consideration was reduced via consumption of two sequential electrons to form radical anion and dianion (EE mechanism). The electrode reaction pathway and the electrochemical parameters of the investigated compound were determined using cyclic voltammetry and convolution - deconvolution transforms. The extracted electrochemical parameters were verified and confirmed via digital simulation method. [ABSTRACT FROM AUTHOR]

The electrodeposition of highly ordered macroporous films of cobalt with regular arrays of spherical pores of the diameters 200, 550, 600, 750 and 1000 nm was carried out into the interstitial spaces of a template formed by polystyrene latex spheres. The spheres were self-assembled on flat gold electrodes of 1 cm² surface area to produce a highly periodic, hexagonal close packed, interconnected network of monodisperse spherical pores within the metal film. The size of pores was determined by the diameter of the polystyrene latex particles used to prepare the template. The nanostructure of the films was studied by the scanning electron microscopy. Magnetic studies of the films were carried out with an Aerosonic 3001 vibrating sample magnetometer. The nucleation and the growth mode of cobalt were investigated via a chronoamperometry study. [ABSTRACT FROM AUTHOR]

The electrochemical and SEM properties of Co2+ ion in hexagonal mesophase of the pluronic lyotropic liquid crystal template are reported. The cyclic voltammetric studies evidenced the occurrence of two slow electron transfer reduction processes. Such a reaction presumably related to the reduction of Co2+ ion to Co metal. The hexagonal (H1) lyotropic liquid crystalline phases of P84 surfactant have been used to template the electrochemical deposition of nanostructured cobalt films as well as its uses as background electrolyte. Electrochemical studies show that these films have very high surface areas, which reveals that the deposited film exhibits promising properties. The electrode parameters of Co(II) ion in hexagonal meso phase of the lyotropic liquid crystal ternary system (pluronic P84/cobalt/ p-xylene) is determined using cyclic voltammetry, deduced convolutive voltammetry and chronoamperometry techniques. The morphology of nanostructured deposited films of Co2+ ion in pluronic lyotropic liquid crystal template was investigated via scanning electron microscopy (SEM) technique. [ABSTRACT FROM AUTHOR]

The polarographic behavior of amiloride hydrochloride has been studied in Britton-Robinson buffers of pH 1.9-11. In acidic medium at Ph< or =2, the dc-polarograms exhibited a single 4-electron cathodic irreversible wave, while at pH values >2, a second two-electron irreversible cathodic wave appeared at a more negative potential. The single or first wave may be attributed to the cleavage of the double bond of the -CH=NH of the imidino amide group with the release of NH(3). While the second wave may be due to the saturation of the C=O of the carboxamide moiety. A polarographic procedure of suffocate sensitivity for the determination of bulk amiloride drug in Britton-Robinson buffer at pH 2 is described. The calibration graph was obtained over the concentration range 2.5 x 10(-5) to 2.5 x 10(-4) M amiloride. The limits of detection (LOD) and quantitation (LOQ) of the procedure were 1 x 10(-5) and 3.3 x 10(-4) M bulk amiloride, respectively. Moreover, a differential-pulse adsorptive cathodic stripping voltammetric procedure has been described to assay of the drug at lower concentration levels. The optimal conditions were: E(acc) = -0.9V, t(acc)=30 s, scan rate=20mV, pulse-height=90 mV and Britton-Robinson buffer of pH 8. The calibration graph was obtained over the concentration range 2 x 10(-8) to 1 x 10(-6) M for bulk amiloride. Both procedures were successfully applied to the determination of amiloride in tablets without the necessity for sample pretreatment or any time-consuming extraction or evaporation steps prior to the drug analysis.

Chlordiazepoxide is a sedative-hypnotic drug widely employed as a transquilizer and anti-depressant. Its electrochemical behavior in Britton-Robinson (B-R) buffers of pH 2-11 at a mercury electrode has been investigated using dc-polarography, cyclic voltammetry and controlled-potential coulometry. Polarograms of the drug in B-R buffers of pH 2-10 exhibited three 2-electron waves, while at pH>10, only a single 4-electron wave was observed. The first, second, and third waves in buffers of pH10) may be due to the reduction of both the N-oxide and C=N centers in a one step. The shift of the E(1/2,) values to more negative potentials upon the increase of pH indicated the involvement of protons in the electrode reaction and that the proton-transfer reaction precedes the electrode process proper. The estimated data indicated that, one proton and two electrons are participated in the rate-determining step of each of the reduced centers. The general sequence of chlordiazepoxide reduction processes via each of its reactant centers may be expressed as: H(+), e, e, H(+)((fast)).Based on the interfacial adsorptive character of the drug onto the mercury electrode, a validated direct square-wave adsorptive cathodic stripping (SWAdCS) voltammetric procedure has been described for the trace determination of the drug in bulk form, tablets and human serum. The procedure did not require sample pretreatment or time-consuming extraction or evaporation steps prior to the assay of the drug. The optimized operational conditions of the proposed procedure have been found to be: accumulation potential E(acc.)=-0.9 V, accumulation time t(acc.)=30s, pulse-amplitude=50 mV, scan increment=10 mV and frequency=120 Hz. The proposed procedure is much more simple, fast, sensitive, costly low and achieved much more lower limits of detection (LOD) (4.4 x 10(-10)M and 6.6 x 10(-10)M) and limits of quantitation (LOQ) (1.5 x 10(-9)M and 2.2 x 10(-9)M), respectively in pharmaceutical formulation and spiked human serum, compared to previously reported methods.