DETERMINATION OF PESTICIDE DIAZINON BY ADSORPTIVE SQUARE-WAVE STRIPPING VOLTAMMETRY WITH DROPPING MERCURY ELECTRODE

A method for trace determination of the pesticide Diazinon using adsorptive square-wave stripping voltammetry (AdSWSV) at the dropping mercury electrode (DME) was described. The pesticide was accumulated at the DME and a well-defined stripping peak was obtained at -1012 mV vs Ag/AgCl/KCI electrode in 0.4 N ammonium acetate electrolyte soluti pH 4.3. Peak current was linear over Diazinon concentration range of 800 – 3200 ppb. Detection limit was 16.49 ppb. Effects of some other pesticides (Chlorpyrifos and Cypermethrin) on Diazinon peak and the recovery of Diazinon from artichoke leaves were studied. The method was extended to the determination of Diazinon in artichoke leaves. The recovery of Diazinon from artichoke leaves was 90.31 - 93.55%. Detection limit was 29.82 ppb. Method had high repeatability and selectivity.

Electrosynthesis and Microstructural Characterization of Anodic VOx Films

Anodic conversion films of vanadium oxides on vanadium were potentiodynamically generated at high voltages in an acetate electrolyte system. The microstructure of the anodic VOx coatings was characterized by surface and solid-state techniques such as scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and x-ray photoelectron spectroscopy. An amorphous structure is proposed in which network-forming [VO4] tetrahedra in various degrees of condensation are connected by distorted [VO5] and [VO6] units. Such polyhedra lead to the formation of nanocrystalline phases of stoichiometric and substoichiometric vanadium oxides, which were observed in the amorphous phase.