Potentiometric estimation of the stability constants of ion-ionophore complexes in ion-selective membranes by the sandwich membrane method: Theory, advantages, and limitations
Potentiometric estimation of the stability constants of ion-ionophore complexes in ion-selective membranes by the sandwich membrane method: Theory, advantages, and limitations
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DOI：
10.1021/ac015564f
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发表时间：
2002-02-01
影响因子：
7.4
通讯作者：
Mikhelson, KN
中科院分区：
文献类型：
--
作者：
Shultz, MM;Stefanova, OK;Mikhelson, KN
本文详细介绍了研究离子选择性膜中离子-离子载体复合物的化学计量和稳定常数的分段夹心膜法。实验数据（报告早些时候在俄罗斯）有关的各种离子与缬氨霉素，与H+-选择性中性离子载体hexabutyltriamido-phosphate，和阴离子结合中性离子载体p-己基三氟乙酰苯甲酸酯的复合物是在一个紧凑的形式。在夹层膜法（存在的内部标准的可靠性，和复杂的化学计量系数的直接测定的可能性）的滴定技术的优点是特别解决。通过计算机模拟，分析了由真实的膜中离子对形成和扩散势引起的常数估计的偏差。讨论了揭示两种不同组成的共存配合物的可能性。
Segmented sandwich membrane method of studying stoichiometry and stability constants of ion-ionophore complexes in ion-selective membranes is considered in detail. The experimental data (reported earlier in Russian) concerning complexes of various ions with valinomycin, with H+-selective neutral ionophore hexabutyltriamido-phosphate, and with anion-binding neutral ionophore p-hexyl trifluoroacetylbenzoate is presented in a compact form. Advantages of titration technique in the sandwich membrane method (the presence of an internal criterion of reliability, and the possibility of direct determination of complex stoichiometry coefficients) are specially addressed. Biases of the estimates of the constants caused by ion-pair formation in real membranes and by diffusion potential are analyzed by means of computer simulations. The possibility of revealing two coexisting complexes with different compositions is also discussed.