Studies on the electrochemical behavior of 3-nitrobenzaldehyde thiosemicarbazone at glass carbon electrode modified with nano-γ-Al2O3

Nano-gamma-Al2O3 is dispersed onto the glass carbon electrode (GCE) by polishing. This nanostructured modified GCE exhibits a great enhancement to the redox responses of 3-nitrobenzaldehyde thiosemicarbazone (3-NBT). In comparison with bare GCE, 3-NBT gives a more sensitive voltammetric response because of the nanoparticle's unique properties. The lowest detectable concentration (3sigma) of 3-NBT is estimated to be 1.18 x 10(-6) M (accumulation for 4 min). The linear relationship between peak current and concentration of 3-NBT holds in the range 1.0 x 10(-5) M to 1.0 x 10(-4) M (r = 0.9981). The electrochemical properties of 3-NBT on this modified electrode have been investigated with various electrochemical methods. The results indicate that the transference of one electron and one proton involves electrode radical reaction processes I and II, respectively. The coverage value (Gamma) of 1.62 x 10(-9) mol cm(-2) was calculated and the electrochemical parameters, diffusion coefficient D (2.54 x 10(-3) cm(2) s(-1), 2.03 x 10(-3) cm(2) s(-1)) and reaction rate constant k(s) (5.9573 s(-1), 7.15 x 10(-2) cm s(-1)) were obtained for quasi-reversible system I and irreversible system II, respectively. (C) 2004 Elsevier Ltd. All rights reserved.