Construction of Novel Chemically Modified Carbon Paste Electrode for Determination of Lead (II) in Different Samples

Molybdophosphate/Mobil crystalline material-41 (MP/MCM-41) composite has been synthesized by the soft templating approach which based on the surfactant self-assembly. Distribution coefficients ( K_d ) of various metal ions were determined using batch technique which showed the high selectivity of Pb²⁺ ions by this cation exchange material. So, the prepared composite has been used as an electro active material for the construction of Pb²⁺ modified carbon paste ion selective electrode (CPE). The modified electrode revealed a linear response over a wide concentration range from 1 × 10^-6 to 1 × 10^-1 mol L^-1 at 25 degree C of Pb²⁺ with a divalent cationic slope of 29.0 ± 0.6 mV decade^-1 and exhibited a detection limit of 8 × 10^-7 mol L^-1 . Moreover, the selectivity coefficient was measured by match potential and separate solution methods. The modified CPE showed a high selectivity and sensitivity for the determination of Pb²⁺ and also showed stable and reproducible response over a period of three months. This method was used for the determination of Pb²⁺ in a lubrication oil sample. The results obtained were coincident with those obtained by the atomic absorption spectrometer