| Abstract
| - Solution studies on the binding properties of 4,5,6,7-tetrathiocino[1,2-b:3,4-b‘]diimidazolyl-1,3,8,10-tetraethyl-2,9-dithione (Et4todit) toward a number of cationic species including some lanthanide ions revealed the occurrence of a selective 1:1 complexation of the ligand withSm3+ ion. Consequently, Et4todit was used as a suitableneutral ionophore for the preparation of novel polymericmembrane (PME) and coated graphite (CGE) Sm3+-selective electrodes. The electrodes exhibit a Nernstianbehavior for Sm3+ ions over wide concentration ranges(1.0 × 10-5−1.0 × 10-1 M for PME and 1.0 × 10-7−1.0 × 10-1 M for CGE) and very low limits of detection(8.0 × 10-6 M for PME and 1.6 × 10-8 M for CGE). Theproposed potentiometric sensors manifest advantages ofrelatively fast response, and, most importantly, goodselectivities relative to wide variety of other cations,including other lanthanide ions. The selectivity behaviorof the proposed Sm3+-selective electrodes revealed a greatimprovement compared to the best previously reportedelectrode for samarium(III) ion. The potentiometric responses of the electrodes are independent of the pH ofthe test solution in the pH range 4.0−6.5. The electrodeswere successfully applied to the recovery of Sm3+ ion fromtap water samples and also, as an indicator electrode, inpotentiometric titration of samarium(III) ions.
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