Abstract
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-chloropheny1) 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
×
10
−7–1.0
×
10
−2
M and 3.5
×
10
−6–1.0
×
10
−2
M with a detection limits of 3.2
×
10
−7
M and 2.3
×
10
−6
M and Nernstian slopes of 20.0
±
0.5, 19.5
±
0.5
mV
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.