PVC Membrane and Coated Graphite Potentiometric Sensors Based on Et<sub>4</sub>todit for Selective Determination of Samarium(III)
作者:Mojtaba Shamsipur、Morteza Hosseini、Kamal Alizadeh、Zahra Talebpour、Mir Fazlollah Mousavi、Mohammad Reza Ganjali、Massimiliano Arca、Vito Lippolis
DOI:10.1021/ac0205659
日期:2003.11.1
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 with Sm3+ ion. Consequently, Et4todit was used as a suitable neutral ionophore for the preparation of novel polymeric membrane (PME) and coated graphite (CGE) Sm3+-selective electrodes. The electrodes exhibit a Nernstian behavior 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). The proposed potentiometric sensors manifest advantages of relatively fast response, and, most importantly, good selectivities relative to wide variety of other cations, including other lanthanide ions. The selectivity behavior of the proposed Sm3+-selective electrodes revealed a great improvement compared to the best previously reported electrode for samarium(III) ion. The potentiometric responses of the electrodes are independent of the pH of the test solution in the pH range 4.0−6.5. The electrodes were successfully applied to the recovery of Sm3+ ion from tap water samples and also, as an indicator electrode, in potentiometric titration of samarium(III) ions.
对 4,5,6,7-tetrathiocino[1,2-b:3,4-b']diimidazolyl-1,3,8,10-tetraethyl-2,9-dithione(Et4todit)与一些阳离子(包括一些镧系离子)的结合特性进行的溶液研究表明,配体与 Sm3+ 离子发生了 1:1 的选择性络合。因此,Et4todit 被用作制备新型聚合物膜 (PME) 和涂覆石墨 (CGE) Sm3+ 选择性电极的合适中性离子载体。这些电极在较宽的浓度范围(PME 为 1.0 × 10-5-1.0 × 10-1 M,CGE 为 1.0 × 10-7-1.0 × 10-1 M)内对 Sm3+ 离子表现出 Nernstian 行为,而且检出限非常低(PME 为 8.0 × 10-6 M,CGE 为 1.6 × 10-8 M)。所提出的电位传感器具有响应相对较快的优点,最重要的是,相对于包括其他镧系离子在内的多种其他阳离子具有良好的选择性。与之前报道的钐(III)离子最佳电极相比,所提出的 Sm3+ 选择性电极的选择性有了很大提高。在 pH 值为 4.0-6.5 的范围内,电极的电位反应与测试溶液的 pH 值无关。该电极被成功应用于自来水样品中 Sm3+ 离子的回收,并作为指示电极用于钐(III)离子的电位滴定。