Abstract
The electrocataylic oxidation of lead(II) was investigated on a novel carbon paste microelectrode modified with a thione-containing ligand namely, N(2-isopropylphenyl)-2-thioimidazole (Hmim). The carbon paste electrode modified with N(2-isopropylphenyl)-2-thioimidazole (CPME-Hmim) was characterized using scanning electron microscope (SEM) and cyclic voltammetry (CV). The electrochemical behavior of lead(II) ions at the modified electrode surface showed one anodic peak at -0.43 V and one cathodic peak at -0.55 V with a separation peak potential of 120 mV. The anodic and cathodic peak current heights of lead(II) ions in the case of CPME-Hmim was much higher than that in the case of the unmodified one, CPE. This is due to the accumulation of lead(II) ions at the surface of CPME-Hmim, forming the monomeric lead(II) complex [(Hmim)(2)Pb(NO3)(2)]. Square wave voltammetry was used for the electrochemical determination of lead(II) ions at CPME-Hmim with optimum conditions and calibration curve (analytical equation: y = -2.129x10(-5) + 1.847x). The obtained results showed a recovery ranged between 98.67-106.11%. The lead(II) ions was determined in different water samples and the obtained results were compared with the data obtained from the ICP-AES instrument.