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 dispersivespectroscopy, atomic force microscopy, and x-ray photoelectron spectroscopy were usedto characterize the deposited electro active polymer film at the surface of glassy carbonelectrodes.The poly(4-Amino-3-hydroxynaphthalene sulfonic acid) modified glassy carbonelectrode was further studied as electrochemical sensor for the determination of selectedalkaloids (ephedrine, theophylline, and caffeine) and organophosphorus pesticides(fenitrothion and methyl parathion) from real samples using various electroanalyticalmethods. The polymer modified electrode showed catalytic effect towards the studiedalkaloids 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 wereachieved. In contrast to most of the previous reports on similar alkaloids and pesticides,po ly( 4-Amino-3-hydroxynaphthalene sulfonic acid) modified glassy carbon electrodegave lower detection limits and excellent recoveries making it potentially applicable forthe 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