Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10Prague 6, Czech Republic.
Electrophoresis. 2010 Jan;31(4):702-8. doi: 10.1002/elps.200900581.
ACE was applied to the quantitative evaluation of noncovalent binding interactions between benzo-18-crown-6-ether (B18C6) and several alkali metal ions, Li(+), Na(+), K(+), Rb(+) and Cs(+), in a mixed binary solvent system, methanol-water (50/50 v/v). The apparent binding (stability) constants (K(b)) of B18C6-alkali metal ion complexes in the hydro-organic medium above were determined from the dependence of the effective electrophoretic mobility of B18C6 on the concentration of alkali metal ions in the BGE using a nonlinear regression analysis. Before regression analysis, the mobilities measured by ACE at ambient temperature and variable ionic strength of the BGE were corrected by a new procedure to the reference temperature, 25 degrees C, and the constant ionic strength, 10 mM. In the 50% v/v methanol-water solvent system, like in pure methanol, B18C6 formed the strongest complex with potassium ion (log K(b)=2.89+/-0.17), the weakest complex with cesium ion (log K(b)=2.04+/-0.20), and no complexation was observed between B18C6 and the lithium ion. In the mixed methanol-water solvent system, the binding constants of the complexes above were found to be about two orders lower than in methanol and about one order higher than in water.
ACE 被应用于定量评估苯并-18-冠-6-醚 (B18C6) 与几种碱金属离子（Li(+)、Na(+)、K(+)、Rb(+) 和 Cs(+)）在甲醇-水混合二元溶剂体系（50/50v/v）中非共价键相互作用。通过非线性回归分析，从 BGE 中碱金属离子浓度对 B18C6 有效电泳迁移率的依赖性，确定了上述水-有机介质中 B18C6-碱金属离子络合物的表观结合（稳定性）常数（K(b)）。在回归分析之前，通过 ACE 在环境温度和 BGE 可变离子强度下测量的迁移率通过一种新程序进行了修正，以参考温度 25 摄氏度和恒定离子强度 10 mM。在 50%v/v 甲醇-水溶剂体系中，与纯甲醇一样，B18C6 与钾离子形成最强的络合物（log K(b)=2.89+/-0.17），与铯离子形成最弱的络合物（log K(b)=2.04+/-0.20），并且 B18C6 与锂离子之间没有络合作用。在混合甲醇-水溶剂体系中，上述络合物的结合常数发现比甲醇低约两个数量级，比水高约一个数量级。
