Novel Approach to the Reaction Analysis of Non-UV-Absorbing Crown Ether with Alkali Metal Ions in Aqueous Solution by Capillary Zone Electrophoresis Using Indirect Photometric Detection

A novel analysis method for complex formation reactions of such a non-UV-absorbing crown ether as 1,4,7,10,13,16hexaoxacyclooctadecane (18-crown-6 ether, 18C6) with alkali metal ions was established through the mobility change in capillary zone electrophoresis. Alkali metal ions at their concentrations of 1x10 mol dm were photometrically detected by using l-ethylquinolinium ion as an indirect photometric reagent. The apparent electrophoretic mobility of alkali metal ions decreased along with the increase in the concentrations of 18C6 in migrating solutions. The complex formation constants analyzed and determined by using the mobility change agreed well with the reported values.