Lead (II)-Selective Potentiometric Sensor Based on Thiophene-2-Aldehyde Thiosemicarbazone (TATS) Schiff Base in PVC Matrix

Abstract

A new Lead (II) PVC membrane sensor incorporating thiophene-2-aldehyde thiosemicarbazone (TATS) as ionophore, tetraphenylborate (NaTPB) in the form of anion excluder and dioctylphthalate (DOP) as a plasticizer was constructed. The optimum membrane prepared with composition, PVC: DOP: Ionophore: NaTPB as 33: 59: 3.4: 4.6 (w/w %), exhibits best results with linear potential response for concentration range (1.0 ×10–7 to 1.0 ×10–2 M) and a slope of 29.4 ± 0.1 mV/decade. The performance of electrode and its electrochemical response to Pb2+ were thoroughly studied and found good over a pH range of 2.4–8.0, with a short response time of < 15 s. The sensor can be used for at least 4 months with reproducibe results and is inert in non-aqueous content up to 15% (v/v). It revealed good selectivity over a wide variety of alkali, alkaline earth and other metal ions. The electrode was successfully applied by using it as an indicator electrode in potentiometric titration of Pb (II) ion with EDTA and indetermination of of Pb2+ ion in some water samples.