Study of Membrane based Ion Selective Electro...

Study of Membrane based Ion Selective Electrode of pyrimidine benzimidazole (PBI) for the selectivity of Cd2+ ion over many interfering ions

Author Name : Dr. Mayank

ABSTRACT

A cadmium ion selective composite cation exchanger pyrimidine benzimidazole (PBI) was used as electro active component for the construction of a ion selective membrane electrode. The membrane electrode are formed by using plasticizer dibutyl(butyl) phosphonate (DBBP),dibutyl phthalate (DBP),1-chloronaphthalelene (CN) and PVC in different composition. The membrane electrode formed by using plasticizer dibutyl(butyl) phosphonate (DBBP)  showed a Nernstian response 31.0 mv per decade for Cd²⁺ ions over a wide concentration range. The electrode works satisfactory in the concentration range 2.5×10^-4 to 1.0×10^-1 M with near Nernstian slope of 31.0 mv per decade of concentration between pH from 2.2 to 5.3.The electrode also showed better selectivity for  Cd²⁺  ion over many interfering ions. Results of the investigation reveal that the membrane electrode prepared by using 5 mg of organic ion exchange PBI , 100 mg DBBP and 150 mg PVC is the best. The performance of the electrodes is comparable with existing electrode in term of working concentration range, slope, pH, response time and selectivity over a number of cations.

Key Words: - Ion selective membrane electrode, plasticizer, pH, Nernstian response, selectivity, solvent effect.