Optimization of Lead-Selective Membrane Electrode Using Central Composite Experimental Design, and Study of Its Behavior with Electrochemical Impedance Spectroscopy
نویسندگان
1 Departmentof Chemistry, Payame Noor University, P.O. Box 19395-4697 Tehran, Iran
2 Department of Chemistry, Faculty of Science, Yazd University, Yazd, Iran
3 Department of Analytical Chemistry, Faculty of Chemistry, University of Kashan, Kashan, Iran
4 Department of Chemistry, Faculty of Science, Yazd University, Yazd, Iran
5 Departmentof Chemistry, Payame Noor University, P.O. Box 19395-4697 Tehran, Iran
doi
چکیده
In this work, response surface methodology in conjunction with central composite design for modeling and optimization of the influence of some process variables (polyvinyl chloride (F1), ionophore (F2), additive (F3) and plasticizer (F4) amounts), on the performance of polyvinyl chloride membrane lead (ІІ) ion-selective electrode is discussed. The slope of 29.1 ± 0.1 mV at the optimal amounts of polyvinyl chloride (0.0283 g), ionophore (0.0074 g), additive (0.002 g) and plasticizer (0.060 g) has been achieved. The electrode exhibited a linear potential response to lead (II) in the concentration range of 1.0 × 10-5 mol L-1 to 1.0 × 10-1 mol L-1 over pH range of 3.0 - 5.5. Greatly, the alternating current impedance technique was applied to investigate the response mechanism of the electrode. The results were obtained from electrochemical impedance spectroscopy shows a linear concentrations range of 1.0 × 10-6 mol L-1 to 1.0×10-1 mol L-1 and in comparison with potentiometry, the pH range increased to 2.5 − 6.0.
