Comparative studies of neodymium (III)-selective PVC membrane sensors.

A PVC membrane sensor for cerium(III) ions based on 1,3,5-trithiane as membrane carrier was prepared. The sensor has a linear dynamic range of 1.0 × 10-1−5.0 × 10-5 M, with a Nernstian slope of 19.4 ± 0.4 mV decade-1, and a detection limit 3.0 × 10-5 M. It has a fast response time of <15 s and can be used for at least 5 months without any considerable divergence in potentials. The proposed sensor revealed comparatively good selectivities with respect to alkali, alkaline earth, and some transition and heavy metal ions and could be used in a pH range of 5.0−8.0. It was used as an indicator electrode in potentiometric titration of oxalate and fluoride ions and in determination of F- ion in some mouth wash preparations.

PVC-Based 1,3,5-Trithiane Sensor for Cerium(III) Ions

A PVC-based membrane of dibenzodiazathia-18-crown-6-dione reveals a Nernstian potentiometric response for Hg2+over a wide concentration range (8.0×10−6 to 1.0×10−2mol dm−3). It has a response time of about 10s and can be used for at least 3 months without any divergence. The proposed electrode revealed very good selectivities for Hg2+ over a wide variety of alkali, alkaline earth, transition and heavy metal ions and could be used in a pH range of 0.5–2.5. It was successfully used as an indicator electrode in potentiometric titration of mercury ions.

Mercury(ii) ion-selective electrode based on dibenzodiazathia-18-crown-6-dione

Mercury(II) Ion‐Selective Electrode Based on Dibenzo‐diazathia‐18‐crown‐6‐dione

The chemistry of the ion-selective optode has recently been recognized as a highly selective ion-sensing methodology which involves a highly selective complexation between an ionophore and a primary ion. This simple methodology allowed the construction of several kinds of ion-sensing devices which enabled highly selective ion determination for analytical purposes. In this review, sensing devices are divided into the following four types with different analytical uses: (1) flow analytical devices (flow-through optode); (2) waveguide devices (waveguide optode); (3) sensing plate devices (sensing plate optode, film optode); (4) fiber-optic devices (fiber optode). The characteristics of each device are explained and discussed with experimental data, and the future prospects for ion-selective optode methodology are described.

Ion-selective optodes : current developments and future prospects

Several 14-membered thia crown ether ionophores having a bulky block subunit were synthesized, and their chemical structures and ion selectivities were examined in detail when these compounds were used as an ion-sensing component of an ion-selective electrode. The ionophores of both cyclic and noncyclic thia ethers exhibited a high selectivity for silver ion (Ag+), in which the sulfur atom in the ionophore molecule plays a role as the effective coordination donor site for the silver ion. The best Ag+-selective electrode was prepared with the 14-membered thia crown ether having one sulfur atom, three oxygen atoms, and a bulky pinan subunit. The ion selectivity of this electrode for Ag+ was over 104 times that for other metal cations. In the case where the sulfide in the thia ether ionophore was changed to sulfoxide by oxidation, ion selectivity for mercury ion became higher; therefore, the sulfoxide was found to be an effective coordination site for the mercury ion. The ion selectivity features of noncycli...

Structural Ion Selectivity of Thia Crown Ether Compounds with a Bulky Block Subunit and Their Application as an Ion-Sensing Component for an Ion-Selective Electrode

Kazuaki Toshima

Papers

Structural Ion Selectivity of Thia Crown Ether Compounds with a Bulky Block Subunit and Their Application as an Ion-Sensing Component for an Ion-Selective Electrode