电喷雾离子化质谱测定冠醚与碱金属离子的结合常数

Determination of Binding Constants of Crown Ether-Alkali Metal Cation Complexes by Electrospray Ionization Mass Spectrometry

应用电喷雾离子化质谱测定络合物结合常数的新方法,将已知结合常数的18 冠6 与K+ 的1∶1络合物溶液([18 冠6…K]+)作为参考络合物加入到待测络合主体二苯并18 冠6 或络合客体Na+ 中,与参考络合物一起竞争络合.通过质谱信号强度的变化,推导出了待测络合物[18 冠6…Na]+、[二苯并18 冠6…K]+ 和[二苯并18 冠6…Na]+的结合常数的对数值lg K—○——分别为4.5,4.9和4.4.

A new method for the determination of binding constants using electrospray ionization mass spectrometry was presented. A complex (^(+)) with a known binding constant value was used as a reference. Then a second host dibenzao-18-crown-6 or guest Na^(+ )was added to compete with reference host or guest. On the basis of the change in intensity of the reference complex, the logarithm values of binding constants of ^(+) ,^(+ )and ^(+) are derived as 4.5,4.9 and 4.4 using a set of simultaneous equilibrium equations.