Novel Lu(III) membrane sensor based on a new asymmetrically S–N Schiffʹs base

In this work we are happy to report the application of a new asymmetrically S–N Schiffʹs base, namely N-(thien-2-ylmethylene)pyridine-2,6-diamine (TPD), in the construction of a novel Lu(III) PVC-based membrane sensor. The linear dynamic range of the sensor lies between 1.0 × 10−2 and 1.0 × 10−6 M, with a LDL, and a Nernstian slope of 8.0 × 10−7 M and 20.5 ± 0.4 mV decade−1, respectively. A membrane composition of 32% poly(vinyl chloride), 58% o-nitrophenyloctyl ether (NPOE), 4% sodium tetraphenyl borate and 6% TPD revealed to lead to the best sensor behavior. The sensor, in addition to its potential response being pH-independent in the pH range of 4.5–8.0, and its at-least-8-week applicability life time, possesses the advantages of fast response time, and very good selectivity over a large number of cations, especially, for lanthanide ions (La3+, Sm3+, Er3+, Tm3+, Ho3+, Dy3+, Yb3+, Pr3+, Nd3+, and Gd3+). It was used as an indicator electrode in potentiometric titration of Lu(III) ions with EDTA, and the recovery of the Lu(III) ions from various binary mixtures.