Abstract
A novel, simple and highly sensitive micro electrode based on carbon paste modified with haematoxylin (HCPME) was suggested for the determination of aluminum. HCPME was prepared by mixing graphite powder and haematoxylin with hot paraffin oil. The surface of the prepared electrode was characterized using scanning electron microscope (SEM). Various experimental parameters, which influenced the electrochemical behavior of HCPME, were optimized. Applying the cyclic voltammetric technique under the optimized conditions, HCPME gave one anodic oxidation peak at + 0.77 V and one reduction cathodic peak at + 0.0 V (vs. Ag/AgCl reference electrode). The proposed method relies on the linear decease of the cathodic peak of haematoxylin offered by square wave voltammogram (SWV) with the addition of Al(III), while the peak potential remains the same. A linear response with Al(III) concentration is observed over the range of 1.0x10(-9) to 1.0x10(-2) mol L-1 with a detection limit of 1.0x10(-9) mol L-1. The relative standard deviation (n= 8) at a concentration level of 1.0x10(-7) mol L-1 is 2.65%. The prepared electrode was successfully applied for the determination of Al(III) in different real water samples. These samples were collected from the underground water of Taif City. In order to investigate the reliability of the suggested electrode, the tested samples were also determined by independent standard method using ICP-OES. The merits offered by the new electrode including small size, simple construction, low cast, good accuracy and high precision.