Development of a novel PVC-membrane fluorescent sensor based on N,N′-bis(dansylamidoethyl)-N,N′-bis(2-pyridylmethyl)propylene-diamine as a new fluoroionophore for highly sensitive and selective monitoring of trace amounts of La3+ ions in aqueous solutions

A new fluorescent sensor for the highly sensitive and selective determination of La3+ ion is developed. The sensing membrane was prepared by incorporating N,N′-bis(dansylamidoethyl)-N,N′-bis(2-pyridylmethyl)propylenediamine (L) as fluoroionophore in the plasticized PVC membrane containing o-NPOE as plasticizer. The proposed sensor displays a wide calibration range of 5.0 × 10−9 to 5.0 × 10−4 M with a low limit of detection of 2.0 × 10−9 M in a solution of pH 6.0. This sensor has a relatively fast response time of less than 2 min. In addition to high stability and reproducibility, it shows a unique selectivity toward La3+ ion with respect to common coexisting cations. The sensor can be regenerated by exposure to a solution of EDTA. The proposed sensor was successfully applied to the determination of La3+ in aqueous solutions.