Abstract: Because neutral molecules have no absolute mobilities, the capillary electrophoresis utilizing peak-shifting experiment can not be used to analyze the interaction of them.In this paper, the neutral molecules have been imparted apparent mobilities by sodium dodecyl sulfate(SDS) micelle, which has negative charge and negative apparent mobilities.The 18-crown-6 and p-nitroaniline without charge under a controlled condition were used as the samples of neutral molecules, and they were able to forMA neutral supramolecule by interaction.Through the research, an interaction analytical method by using capillary electrophoresiSIs set up.The logarithm of binding constant of 18-crown-6 with p-nitroaniline was obtained to be 4.14.In addition, comparative differences of hydrophobicity between 18-crown-6 and p-nitroaniline to SDS was found, respectively.Further more, for multiple interactions, the interaction analytical method of supramolecules has also been set up, which has more accuracy and availability.The logarithms of binding constant of 18-crown-6 to 2-aminopyridine and SDS, and 2-aminopyridine to SDS were obtained to be 3.65, 3.13 and 1.15, respectively.After the development of the peak-shifting was applied to the neutral molecules, the principles, available experimental conditions, and assumptionSIn the measurement have been discussed.This approach in this paper could be developed as an interaction analysis method of multiple componentSIn a complex system.

Key words: Interaction, Supramolecule, Capillary electrophoresis, 18-Crown-6, Neutral molecule