Open-tubular capillary electrochromatography using capillary columns chemically bonded with the new host molecules calix[6]crown, calix[6]arene.

Two host molecules, p-tert-butylcalix[6]-1,4-crown-4 and p-tert-butylcalix[6]arene were prepared and attached onto the inner surfaces of capillaries for open-tubular electrochromatography with the aid of gamma-glycidoxypropyl-trimethoxysilane (KH-560) as bridging agent. The successful bonding was confirmed by infrared (IR) results and greatly decreased electroosmotic flow (EOF). Parameters affecting separation, such as buffer pH and organic modifier were studied. The two novel stationary phases were evaluated by the separation of isomeric toluidines, a mixture of pyridine and isomeric picolines, and isomeric dihydroxybenzenes; comparisons between capillaries coated with the two stationary phases and bare capillary were investigated. The special selectivity of these two novel stationary phases showed a certain extent of supramolecular interactions between stationary phases and solutes.