title: Discrimination of methylammonium from organic ammonium ions using ion-selective electrodes based on calix[4]arene-crown-6 conjugates.
abstract: Calix[4]-bis-2,3-naphtho-crown-6 can be used to discriminate between methylammonium and other organic ammonium ions. An electrode based on this ionophore, potassium tetrakis(p-chlorophenyl)borate (20 mol% relative to the ionophore) as an ionic additive and bis(2-ethylhexyl) sebacate as a solvent mediator in a poly(vinyl chloride) membrane matrix, displayed higher selectivity for methylammonium than for various other organic ammonium ions. However, there was considerable interference by inorganic cations, especially Cs+. Similar calix[4]arene-crown-6 conjugates, such as calix[4]-bis-1,2-benzo-crown-6, calix[4]-bis-crown-6, 1,3-dioctyloxy-calix[4]arene-crown-6, 1,3-diisopropoxy-calix[4]arene-crown-6 and 1,3-dimethoxy-calix[4]arene-crown-6 were less effective in discriminating methylammonium.
authors.affiliation: Faculty of Pharmaceutical Sciences, Okayama University, Tsushima, Okayama 700-8530, Japan. katsu@pheasant.pharm.okayama-u.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Katsu
authors.forename: M
authors.initials: M
authors.lastname: Matsumoto