Development of a potentiometric sensor for europium(III) based on N, N, N′, N′-tetraoctyldiglycolamide (TODGA) as the ionophore

Abstract

A polymer inclusion membrane (PIM) with N,N,N′,N′-tetraoctyl diglycolamide (TODGA) as the ionophore and polyvinyl chloride (PVC) as the base polymers was synthesized and evaluated for potentiometric membrane sensing of Eu3+ ions. Effects of membrane composition, inner filling solution and pH on the electrode performance were investigated and it was found that the membrane with a composition of 30.3% TODGA, 9.1% NaTPB and 60.6% PVC showed a wide linear dynamic range (1.5×10−6M to 1.2×10−2M) with a slope of 17.3±0.1mV per decade with 1.2×10−6M as the limit of detection for Eu3+. Interference from mono-, di-, tri-, tetra- and hexa-valent ions was investigated by matched potential method. The sensor was also tested as an indicator electrode in the titration of Eu3+ with standard EDTA solution. The response time of the proposed sensor was found to be <10s. The life time of the sensor electrode was found to be one month under optimized storage conditions. The potentiometric sensor as developed was employed in the determination of Eu3+ in the synthetic mixture of uranyl nitrate and europium nitrate, after the removal of major matrix using 30% TBP-n-dodecane. The analytical results, compared with those obtained from inductively coupled plasma - atomic emission spectroscopy (ICP-AES), showed good agreement between the two methods.