ANODIC VOLTAMMETRIC BEHAVIOR OF IODIDE AT A CHITOSANMODIFIED GLASSY CARBON ELECTRODE

A novel anodic stripping voltammetry for the determination of iodide with a chitosan-modified glassy carbon electrode (CMGCE) has been described. The CMGCEs were able to preconcentrate iodine due to the oxidation of iodide at + 0.7V (vs. SCE) in pH = 3.80 sulfuric acid, after equilibration at +0.1V for 25 s, an anodic scan was performed from +0.1 to +1.2V at 100mV/s, and a well-defined peak could be obtained at about + 0.85 V. The peak current also varied linearly with the concentration of iodide over the range 0.1 ~ 0.75 µg/mL, and the detection limit was 0.05 µg/mL. The conditions for determining iodide and the possible electrode reaction processes were discussed. The method has been applied to the detection of iodide in cydiodine tablets with satisfactory results.