Potentiometric Determination of Aluminium Ions Using Carbon Paste Electrode by Benzo 15 –crown – 5 as a modifier

Carbon paste is an ideal electrode substrate due to its; chemical inertness, low cost, fast response time, ease of fabrication in different configuration and size and renewal. These attractive features of carbon electrodes are the reason for the considerable attention at the production of carbon based electro analytical sensors. Recently, carbon paste technique was used in the construction of amperometric enzyme electrode, urea and potentiometric determination of drug. a new modified carbon paste electrode based on benzo 15 – crown – 5 as a modifier was prepared for the determination of Aluminium ions. The best results were obtained from the composite sensor with the electrode composition of 1.81% modifier, 23.99% paraffin oil, 1.48% sodium tetra phenyl borate and 73.88% graphite powder. The proposed electrode shows a Nerstian slope 19.54 mV in the concentration of 1×10-7 to 1×10-3 mol/L of Aluminium ions with detection limit of 5×10-7 M. Response of electrode in the pH is fixed between 5 and 8. The sensor exhibits good selectivity for Aluminium ions over a wide variety of other cations. It can be used as an indicator electrode in potentiometric titration of Aluminium ions. The electrode has a response time of about 40 seconds and can be used 21 days without a serious change in sensitivity.