Ion-selective carbon paste electrode based on new tripodal ligand for determination of cadmium (II)

A new chemically modified carbon paste electrode for Cd(II) ions based on 3,5-dinitro-N-(tri-2-pyridyl methyl) benzamide (DNTPMBA) as an ionophore was prepared. The electrode exhibits a Nernstian response for Cd(II) ions over a wide concentration range (2.16 x 10(-7)-1.00 x 10(-1) mol L-1) with a slope of 30 +/- A 1 mV per decade. It has a response time of about 50 s and can be used for a period of 3 months with good reproducibility. Detection limit obtained in the optimal conditions was 1.82 x 10(-7) mol L-1. The electrode was successfully used for potentiometric determination of Cd(II) in well water. The pH influence and interference of some cations were also studied.