A new modified glassy carbon electrode (GCE) based on a synthesized N-(2-aminoethyl)-4,4′-bipyridine (ABP) was developed for the determination of Ag(I) by differential pulse voltammetry (DPV). ABP was covalently immobilized on GC electrodes surface using 4-nitrobenzendiazonium (4-NBD) and glutaraldehyde (GA). The Ag(I) ions were preconcentrated by chemical interaction with bipyridine under a negative potential (−0.6 V); then the reduced ions were oxidized by differential pulse voltammetry and a peak was observed at 0.34 V. The calibration curve was linear in the concentration range from 0.05 μM to 1 μM Ag(I) with a detection limit of 0.025 μM and RSD = 3.6%, for 0.4 μM Ag(I). The presence of several common ions in more than 125-fold excess had no effect on the determination of Ag(I). The developed sensor was applied to the determination of Ag(I) in water samples using a standard addition method.

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Nanoparticles of 4,4′-bipyridine-silver coordination polymer were used for the modification of glassy carbon electrode with applications in analytical chemistry.

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The anticholinesterase activity of four biochemical pesticides: spinosad, pyrethrum, neem bark extract and veratrine was tested against one acetylcholinesterase extracted from Electrophorus electricus and two from Drosophila melanogaster. Pyrethrum, neem bark extract, and veratrine induced a dose-related inhibition of a variable type. Electric eel cholinesterase was inhibited uncompetitively by neem bark extract, the inhibition of the wilde-type fruit fly enzyme by pyrethrum was competitive, and the other enzyme-biochemical pesticide inhibitions were non-competitive. The sensitivity of each enzyme toward biochemical pesticides was variable.