New silver selective electrode fabricated from benzothiazole calix[4]arene: Speciation analysis of silver nanoparticles

A new calix[4]arene containing benzothiazolyl pendants was synthesized and used as an ionophore to fabricate macro- and micro-Ag+ selective membrane electrodes. PVC membranes plasticized with NPOE provided better selectivity coefficient towards Ag+ than those plasticized with DOS. The selectivity coefficients (logK(Ag.j)(pot)) for macro- and microelectrode were, respectively, -2.8 and -2.5 for Hg(II) and lower than -4.0 and -3.5 for other cations tested. The fabricated electrodes can be used in a wide pH range (pH 2-8) with a response time less than 5s. The electrodes exhibit near theoretical Nernstian slope (59.7 +/- 0.8 mV decade(-1) for macroelectrode and 59.8 +/- 1.0 mV decade(-1) for microelectrode) with low detection limits (ca. 5.0 x 10(-7) M) and wide linear working range (10(-6) to 10(-2) M). The electrodes were used as an indicator electrode for the argentometric titration of the mixture of Cl- and Br-. The fabricated electrodes were also used for the first time in speciation analysis of Ag nanoparticles with good accuracy and precision. This Ag-ISE should be beneficial to researches regarding Ag nanoparticles. (C) 2008 Elsevier B.V. All rights reserved.