Ali A. Ensafi, Fatemeh Rezaloo, B. Rezaei,

In this paper, a glassy carbon electrode (GCE) was modified with polyzincon. The modified electrode was used as a simple, inexpensive and highly sensitive
electrochemical sensor for the determination of organophosphorus pesticide fenitrothion. To fabricate the electrochemical sensor, GCE was immersed in 0.10 mmolL1 zincon solutions at pH 7.0 and then successively scanned between 1.00 to 2.20 V (vs. Ag/AgCl) at a scan rate of 70 mVs1 for six cycles. The morphology and structure of the polyzincon were studied with atomic force microscopy and scanning electron microscopy. A comparison of the electrochemical behavior of fenitrothion on the unmodified and polyzincon modified-GCE showed that in the modified electrode not only the oxidation peak current increased, but also the overpotential shifted to lower one. The experimental conditions such as sample solution pH, accumulation potential, and time were optimized. The differential pulse voltammetric responses of fenitrothion at potential about 0.60 V was used for the determination of fenitrothion. The peak current increased with increasing
the concentration of fenitrothion in the range of 5 to 8600 nmolL1 with a detection limit of 1.5 nmolL1. Finally, the electrochemical sensor was used for the
analysis of fenitrothion in water and fruit samples.