Electrochemical Determination of Methyl Parathion Using Poly-(2-Amino-5-Mercapto-1,3,4-Thiadiazole) Nano-Film Modified Electrode

2-Amino-5-nnercapto-1,3,4-thiadiazole (AMT) was electrochemically polymerized on glassy carbon electrode (GCE) surface to fabricate a nano-film modified electrode (PAMT/GCE). Morphology of the obtained PAMT/GCE surface was characterized with scanning electronic microscopy (SEM). Eletrochemical behaviors of methyl parathion (MP) at the PAMT/GCE were thoroughly investigated. It was found that the oxidation peak potential shifted negatively, and the reduction peak potential shifted positively. Compared with the unmodified glassy carbon electrode, peak currents of MP at the PAMT/GCE increased significantly. Based on this, a highly sensitive electrochemical method was developed for the determination of MP. Under the optimal conditions, the peak currents were linearly proportional to MP concentrations (c) in the range from 7.0 x 10(-8) to 1.0 x 10(-5) mol L-1 with an equation of I-p (mu A)=3.918 c (mu mol L-1) + 4.550 (R = 0.994). The estimated detection limit was 4.8 x 10(-8) mol L-1 (S / N = 3). The proposed method was successfully applied to determine MP in fruits.