Conducting Polymer Modified Electrodes for the Electrochemical Determination of Alkaloids and Pesticides
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Date
2013
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Addis Ababa, Ethiopia
Abstract
4-Am ino-3 -hydroxynaphthalene sulfonic acid was electropolymerized
potentiodynamically from aqueous solution at the surface of glassy carbon electrodes.
Different Electrochemical and surface characterization techniques like cyclic
. vo ltammetry, impedance spectroscopy, scanning electron microscopy/energy dispersive
spectroscopy, atomic force microscopy, and x-ray photoelectron spectroscopy were used
to characterize the deposited electro active polymer film at the surface of glassy carbon
electrodes.
The poly(4-Amino-3-hydroxynaphthalene sulfonic acid) modified glassy carbon
electrode was further studied as electrochemical sensor for the determination of selected
alkaloids (ephedrine, theophylline, and caffeine) and organophosphorus pesticides
(fenitrothion and methyl parathion) from real samples using various electroanalytical
methods. The polymer modified electrode showed catalytic effect towards the studied
alkaloids and organophosphorus pesticides. For the investigated alkaloids and pesticides,
detection limits in the range of4.7-79 x 10.8 M and 0.79-1.1 x 10-9 M, respectively were
achieved. In contrast to most of the previous reports on similar alkaloids and pesticides,
po ly( 4-Amino-3-hydroxynaphthalene sulfonic acid) modified glassy carbon electrode
gave lower detection limits and excellent recoveries making it potentially applicable for
the determination of alkaloids and pesticides in environmental samples.
The electrochemical behavior of fenitrothion at an electrochemically activated glassy
carbon electrode was also investigated. The current response showed linear dependence