Cation slectivity of poly(vinyl chloride) membranes based on cryptands with thiourea fragments

Supramolecular Based Membrane Sensors

“…The electrode function was linear within the activity range 10 -1 -10 -4 M, with a slope of 48±1 mV per decade. Selectivity coefficients were reported to be 0.005 for Li + , 0.006 for Na + , 0.015 for K + , 0.012 for Cs + , 0.006 for NH 4 + , 0.0027 for Mg 2+ , 0.0032 for Ca 2+ , 0.0040 for Sr 2+ and 0.0081 for Ba 2+ [111]. …”

PVC Membrane and Coated Graphite Potentiometric Sensors Based on Dibenzo‐21‐Crown‐7 for Selective Determination of Rubidium Ions

“…According to this method, a specified activity (concentration) of the primary ion A is added to a reference solution and the potential is measured. In Table 2 are also compared the selectivity coefficients slopes and linear ranges of the proposed sensors with those of the previously reported Rb þ ion-selective electrodes (Convington et al 1988;Lukyanenks et al 1992;Saleh 1994). The selectivity coefficient is then K A,B Pot given by the resulting primary ion to interfering ion activity (concentration) ratio, K A,B Pot ¼ a A /a B .…”

“…Because macrocyclic crown ethers can form selective and stable complexes with metal ions of compatible dimensions (Izatt et al 1985;Izatt et al 1991) and can potentially applied to their separation and determination (Yoshio and Nogachi 1982;Takagi and Nakamura 1986;Janzen 1991;Shih 1992), they have also been used extensively in construction of PVC-based ion-selective electrodes (Shih 1992;Morf et al 1979;Janata et al 1998;Bühlmann et al 1998). However, in comparison with other alkali and alkaline earth cations, a limited number of membrane sensors for Rb þ ion have been demonstrated (Convington et al 1988;Lukyanenks et al 1992;Saleh 1994), probably due to the absence of a known biological role for this cation. However, in comparison with other alkali and alkaline earth cations, a limited number of membrane sensors for Rb þ ion have been demonstrated (Convington et al 1988;Lukyanenks et al 1992;Saleh 1994), probably due to the absence of a known biological role for this cation.…”

Ionophores in Rubidium Ion‐Selective Membrane Electrodes

“…The Rb þ selective electrode based on bis(2' : 3', 9' : 10'-dibenzo-16-crown-5)-6-yl 2,6-pyridine dicarboxylate with dioctyl phthalate as a plasticizer was constructed [12]. The other Rb þ selective electrode based on 1,3,12,14-tetraaza-6,9,17,20,25-pentaoxabicyclo[12.8.5] heptacosane-2,13-dithione was constructed [13].…”