A novel ion selective sensor for promethium determination

This is a first promethium(145) ion-selective sensor based on the comparative study of two Schiff base ligands (X-1 and X-2) as neutral ionophores. Effect of various plasticizers: 2-nitrophenyloctylether (o-NPOE), dibutyl phosphonate (DBP), dioctylphthalate (DOP), tri-(2-ethylhexyl) phosphate (TEHP), dibutyl butylphosphonate (DBBP), chloronaphthalene (CN) and anion excluders: potassium tetrakis (p-chlorophenyl) borate (KTpClPB), sodiumtetraphenylborate (NaTPB) and oleic acid (OA) have been studied. The membrane with a composition of ionophore (X-1/X-2):KTpClPB:PVC:o-NPOE (w/w, %) in the ratio of 5:5:30:60 exhibited best performance. The best responsive membrane sensors (8 and 21) exhibited working concentration range of 4.5 x 10(-7)-1.0 x 10(-2) M and 3.5 x 10(-6)-1.0 x 10(-2) M with a detection limits of 3.2 x 10(-7) M and 2.3 x 10(-6) M and Nernstian slopes of 20.0 +/- 0.5,19.5 +/- 0.5 my decade(-1) of activity, respectively. The sensor no. 8 works satisfactorily in partially non-aqueous media up to 10% (v/v) content of methanol, ethanol and acetonitrile. Analytical application of the proposed sensor has been demonstrated in determination of promethium (III) ions in spiked water samples. (C) 2010 Elsevier B.V. All rights reserved.