Cd (II) Ion-Selective Electrode Based on 2 –Acetylthiophene Semicarbazone in Polymeric Membrane

A new PVC membrane sensor for Cd+2 ions has been prepared using 2–acetylthiophene Semicarbazone ligand as an ionophore and dibutylphthalate (DBP) as a plasticizing agent. The best performance was recorded with a membrane composition of PVC: DBP: Ionophore: NaTPB as 31: 64: 3.2: 1.8 (w/w %). The sensor exhibits a Nernstian response for Cd+2 ions over a wide concentration range (1.0 ×10–5 to 1.0 ×10–1 M) with a slope of 29.4 ± 0.2 mV decade–1. It has a fast response time of ˂ 10 s and can be used for at least 5 weeks without any divergence in potential. The electrode can be used in the pH range from 3.4 to 7.6. The proposed sensor was successfully applied for the direct determination of Cd+2 in solutions and, as an indicator electrode, in potentiometric titration of cadmium ions using EDTA as titrant.