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 ( log   K 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 5 s. 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 × 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.