Fabrication of ion selective electrode for detection of lead ion based on aqueous sol-gel method.

Ion selective electrodes (ISE) based on sol–gel process usingtetraethoxysilane(TEOS), diethoxydimethylsilane(DEDMS) and oxalic acid as ionophore, was successfully developedfor detection of Pb2+in aqueous solution.The response of the electrode and also its characterization were estimated by different methods includingpotentiometry measurement, Fourier TransformInfrared (FTIR) and scanning electron microscopy (SEM). The results indicate that the electrode response depends onionophore concentration. In these ion selective electrodes, 0.5 wt.% oxalic acid gives the best sensitivity for Pb2+.The sol–gel electrodeshows linear response with Nernstian slope of 28.63 mV/decade toward lead ionover the concentration range 6.1×10–6 to 1.7×10–2. Also, the electrodes shown detection limits of 1.0×10−7 M. The response time of this electrode was obtained 15 sec. at linear dynamic range and lifetime of nearly 2 months.The electrodeis suitable for use in aqueous solutions in a wide pH range of 4–6.All the obtained results indicate that the proposed lead ion sensor electrode have good reproducibility, repeatability, stability, selectivity and a fast response time.