Determination of unbiased selectivity coefficients of neutral carrier-based cation-selective electrodes
Determination of unbiased selectivity coefficients of neutral carrier-based cation-selective electrodes
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DOI：
10.1021/ac960891m
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发表时间：
1997-03-15
影响因子：
7.4
通讯作者：
Bakker, E
中科院分区：
文献类型：
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作者：
Bakker, E
建立了一种确定基于中性载体的阳离子选择性电极的选择性系数的新程序，避免在测量辨别离子之前暴露于首选离子。因此，该方法不受膜中首选离子存在的影响，否则可能会掩盖对辨别离子溶液的响应。只要满足一系列考虑因素，它通常是适用的，并且只能对给定的膜应用一次。对一系列钠、银和钙选择性电极的仔细研究表明，现在甚至可以针对高度辨别的阳离子获得能斯特响应斜率。具体来说，Yamamoto 和 Shinkai 引入的 1,3-桥接杯 [4] 芳烃衍生物确实产生了非凡的钠选择性 log K-Na,K(pot) = -4.9，其中钾也显示出能斯特响应，使用两种不同的银载体（双硫醚官能化的杯[4]芳烃和亚甲基双（二异丁基二硫代氨基甲酸酯））以及钙载体 ETH 129 进行类似测量也显示出极高的选择性，这可以令人满意地与之前在离子缓冲溶液中获得的数据相关联。新程序有望成为未来表征高选择性离子载体的有价值的附加工具。
A new procedure for the determination of selectivity coefficients of neutral carrier-based cation-selective electrodes is established that avoids exposure to the preferred ion prior to the measurement of discriminated ions, The method is, therefore, unbiased by the presence of preferred ions in the membrane that otherwise could mask the response to discriminated ion solutions. It is generally applicable as long as a series of considerations are met and can only be applied once for a given membrane, Careful studies with a series of sodium-, silver-, and calcium-selective electrodes reveal that Nernstian response slopes can now be obtained for even highly discriminated cations, Specifically, a 1,3-bridged calix[4]arene derivative as introduced by Yamamoto and Shinkai indeed yields an extraordinary sodium selectivity of log K-Na,K(pot) = -4.9, with potassium showing Nernst response as well, Analogous measurements with two different silver carriers, a bisthioether-functionalized calix[4]arene and methylenebis(diisobutyldithiocarbamate), and the calcium carrier ETH 129 also show extremely high selectivity, which can satisfactorily be correlated to data obtained previously in ion-buffered solutions. The new procedure promises to be a valuable additional tool for future characterizations of highly selective ion carriers.