Preparation of a New selective PVC Membrane Electrode forCopper(II) Ion Based on Complex of 1,3-diphenyl-5- (P-nitrophenyl) Formazan as Ionophore with Copper(II).

A new selective PVC (poly vinyl chloride) membrane electrode for Copper(II) ion was prepared depending on a complex of 1,3-diphenyl-5-(P-nitrophenyl) formazan (FM) as ionophore with copper(II). The best performance was obtained by a membrane electrode with the composition: PVC as matrix (32 %), (FM) as ionophore (3 %), DBP (Dibutyl phthalate) as plasticizer (64%), and NaTBP (Sodium tetraphenylborate) as anionic additive (1%). This electrode exhibited a linear potential response to copper(II) in the concentration range 1.0 × 10−6 – 1.0 × 10-1 M with Nernstian slope of 28.23 mV/decade and detection limit down to 7 × 10−7 M, a response time of about 15 secs, and a life time which exceededtwo months over a wide range of PH:3-6. The suggested PVC electrode had a high selectivity for copper over a large number of alkaline and alkaline earth ions and some heavy metals ions. Described membrane electrode could be successfully used in analytical measurements by direct potentiometry for the determination of Cu+2 in standard and real sample solutions.