Study On Interaction Of Substances Of Supramolecular System By Capillary Electrophoresis

A lot of work has been done in the field of interaction analysis by capillary electrophoresis, and a great deal of achievement has been gained. But the objects of interaction analysis by capillary electrophoresis are limited to measurement of the interaction of charged substitutes. The study of interaction between two uncharged neutral substitute molecules hasn't been reported, because interaction analysis by capillary electrophoresis is based on that the mobility of binding compound must be different from that of substitute molecule. For the interaction of the two neutral substitute molecules, whereas, the mobilities of the two molecules and their binding compound are equal to zero in a normal electrolyte.The principle of separation of neutral solutes with micelle of charged surfactant by micellar electrokinetic capillary chromatography was cited in the paper. The micelle of charged surfactant, which was employed as the charged competitive legand in buffer, was introduced to interaction analysis by capillary electrophoresis. So the third charged substitute was added to the interaction system formed by one neutral host molecule and one neutral guest molecule. Therefore, the model of charged competitive ligand was established. The neutral guest molecule interacted with the charged micellar phase primarily because of hydrophobic interaction. That led the mobility of the neutral guest molecule change, so the changed mobility was considered as the mobility of the neutral guest molecule endowed by charged micellar. The mobility changed again along with the neutral host molecule added to the buffer which contained charged micelle. So the intensity of interaction of the neutral guest molecule and the neutral host molecule can be measured by the peak-shift method of capillary electrophoresis interaction analysis.Three kinds of uncharged neutral supramolecular systems were studied in this paper, and micelle of sodium dodecyl sulfate was used as the charged competitive ligand in interaction analysis. There are the system of ?-naphthol and ?-cyclodextrin; the system of phenol and & -cyclodextrin and the system of 2-aminepyridine and 18-crown-6. For the systems of ?- cyclodextrin, the binding constants of the neutral guest molecules with sodium dodecyl sulfate resolvedfirstly, the binding constants of the neutral guest molecules with P -cyclodextrin were gained. The values of the binding constant obtained are consistent with those in published literatures Therefore the validity of the idea and the model was approved. But for the system of 2-aminepyridine and 18-crown-6, the binding constants of 2-aminepyridine with sodium dodecyl sulfate and 18-crown-6 with sodium dodecyl sulfate were firstly resolved, respectively, because there was one more interation of 18-crown-6 and sodium dodecyl sulfate in the system than that in the systems of P -cyclodextrin. The binding constant of 2-aminepyridine with 18-crown-6 was measured.In addition, the peak-shift model for charged substitutes was employed to the practical researches. The intensity of interaction of antibacterial sodium houttuyfonate and b -cyclodextrin was investigated, the stability constant of the inclusion compound formed by them was measured. Further, the different intensity of interaction of chiral reagent of?-cyclodextrin and enantiomers was employed to chiral separateion of the right zomig and its enantiomer. All results are satisfied.The results indicated that through the introduced charged competitive legand, the established experimental models and mathematic equations, the binding constant of the uncharged guest and the uncharged host molecules can simply be resolved. The interaction analysis by capillary electrophoresis has been extended tobetween the uncharged neutral substitute molecules.