Design and characterization of sodium-selective optode membranes based on the lipophilic tetraester of calix[4]arene

Abstract

Four types of lipophilic calixarene ionophores have been used in the design of sodium-selective optode membranes. Plasticized poly(viny1 chloride) (PVC) membranes incorporating the tetraester of calix[4]arene and a neutral H+-selective chromo-ionophore (ETH 5294) have proved to be excellent reversible sensing devices for the optical determination of the sodium cation in pH-buffered solutions. At pH 9.0, the absorbance response of the optode shows a good correlation with the theoretically derived formula in the range from 1 X 10-6 to 10-2 moll-' sodium ion. Dynamic range, reproducibility, response time and the selectivity of the new optode membranes are discussed.

A fast response cadmium-selective polymeric membrane electrode based on N,N′-(4-methyl-1,2-phenylene)diquinoline-2-carboxamide as a new neutral carrier

“…Since less than three decades ago the solid-state ISE based on a mixed CdS/Ag 2 S membrane has been commercially available [16]. Polymeric carrier-based ion-selective electrodes (ISEs) for determining the alkali metal cations such as sodium [17,18], potassium and lithium [19] have been studied numerously. The efforts are needed to make ion-selective electrodes for heavy metal ions in very low concentration [20,21], so we were interested in preparation of a new solvent polymeric membrane electrode for selective and fast monitoring of cadmium ion in solutions.…”

Ionic optodes: role in fiber optic chemical sensor technology

“…65,67,85 Exposure over periods between 2 and 72 h in analyte-free buffers results in decreased signal intensity. In one case, covalent attachment of the reporter dye to the PVC matrix was shown to substantially reduce this signal loss, but with a commensurate ®ve-fold increase in response time; from about 3 min to 15 min.…”

Ion sensing film optodes based on chromogenic calix[4]arene: application to the detection of Hg2+, Ni2+ and Eu3+ ions

“…Optical sensing of many cations has been reported such as sodium [11,12], potassium [13,14], lithium [15,16], ammonium [17], calcium [18,19], mercury [20,21] and lead [22,23]. In optical sensors the concentration dependence of the signal is a direct result of the interaction of the carrier/ receptor molecule (ligand, ionophore) with the metal ions to be analyzed.…”