Zahra Heidari - Department of Chemistry, Faculty of Science, Mashhad Branch, Islamic Azad University, Mashhad, Iran
Mahboubeh Masrournia - Department of Chemistry, Faculty of Science, Mashhad Branch, Islamic Azad University, Mashhad, Iran.

Box–Behnken designs were used as experimental design method to optimize the influence ofingredients of membrane on the electrode performance. A nanocomposite was designed by using2-hydroxy-1, 4-naphthoquinon as ion carrier with multi-wall carbon nanotubes (MWCNTs), inorder to determination of Ce(IV). Box–Behnken response surface was led to find a model foroptimizing the response. The best performance was obtained with 5 % wt of lawsone, 10 % wt ofMWCNTs, 20 % wt of paraffin oil and 65 % wt of graphite powder. The optimized membraneelectrode shows a Nernstian response (15.08±0.2 mV decate-1) toward Ce(IV) ions in linear rangefrom 1.0×10-7 to 1.0×10-2 mol L-1 with a detection limit of 5.0×10-8 mol L-1. The proposed sensorwas employed in pH range of 4 to 8 with a fast response time (10 s).

Box-Behnken design, Cerium(IV) Carbon paste electrode, Multi-wall carbonnanotubes, Potentiometry; Lawsone