Electrochemical oxidation of niclosamide at a glassy carbon electrode and its determination by voltammetry

Cyclic voltammetry, square-wave voltammetry and controlled potential electrolysis have been used to study the electrochemical oxidation behaviour of niclosamide at a glassy carbon electrode. The number of electrons transferred, the wave characteristics, the diffusion coefficient and reversibility of the reactions have been investigated. Following optimisation of voltammetric parameters, pH, and reproducibility, a linear calibration curve over the range 1 x 10-6 – 1 x 10-4 mol dm-3 niclosamide was achieved. The detection limit was found to be 8 x 10-7 mol dm-3. For eight successive determinations of 1 x 10-5 mol dm-3 niclosamide, a relative standard deviation of 3.6% was obtained. This voltammetric method was applied for the determination of niclosamide in tablets. KEY WORDS: Niclosamide, Electrochemical oxidation, Cyclic voltammetry, Square wave voltammetry, Glassy carbon electrode, Determination of niclosamide  Bull. Chem. Soc. Ethiop. 2003, 17(1), 95-106

Rapid Synthesis of Thiol-Co-Capped-CdTe/CdSe/ZnSe Core Shell-Shell Nanoparticles

CdTe QDs has been demonstrated in many studies to possess good outstanding optical and photo-physical properties. However, it has been established from literature that the toxic Cd2+ that tends to leak out into nearby solutions can be protected by less toxic ZnS or ZnSe shells leading to the synthesis of core-shells and multi-core-shells. Hence, this has allowed the synthesis of CdTe multi-core-shells to have gained much interest. The preparation of most CdTe multi-core-shells reported from various studies usually has a longer reaction time (6–24 h) in reaching their highest emission maxima. The synthesis of CdTe multi-core-shells in this study only took 35 min to obtain a highest emission maximum compared to what has been reported from the literature. CdTe multi-core-shells were synthesized by injecting 7, 14, and 21 mL each of Zn complex solution and Se ions into the reacting mixture containing CdTe core-shells (3 h) at 5 min intervals over a 35 min reaction time. The emission maxima of the MPA-TGA-CdTe multi-core-shells at 21 mL injection was recorded around 625 nm. Therefore, we are reporting the rapid synthesis of five different thiol co-capped CdTe/CdSe/ZnSe multi-core-shell QDs with the highest emission maxima obtained at 35 min reaction time

Synthesis of pH sensitive dual capped CdTe QDs: their optical properties and structural morphology

We herein report five different types of thiol dual capped cadmium tellurite quantum dots (CdTe QDs) namely glutathionemercapto-propanoic acid (QD 1), glutathione-thiolglycolic acid (QD 2), L-cysteine-mercapto-propanoic acid (QD 3), L-cysteinethiol-glycolic acid (QD 4) and mercapto-propanoic acid-thiol-glycolic (QD 5). Dual-capped CdTe QDs were prepared using a one pot synthetic method. Cadmium acetate and sodium tellurite were respectively used as cadmium and tellurium precursors. Photo-physical properties of the synthesized QDs were examined using UV-Vis and photoluminescence spectroscopy while structural characterization was performed by means of transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy