CAPILLARY ELECTROPHORETIC DETERMINATION OF DIFFERENT CLASSES OF ORGANIC IONS BY POTENTIOMETRIC DETECTION WITH COATED-WIRE ION-SELECTIVE ELECTRODES

Singly charged amines and sulfonic acids as cationic and anionic aliph atic model substances, respectively, were detected in capillary electr ophoresis with all-solid-state ion-selective electrodes. The sensitivi ty for these compounds is a function of their lipophilicity. The signa l detected is generally greater for molecules with a larger organic pa rt. The utility of the method is further demonstrated by the detection of a group of aromatic compounds in the form of the anionic analgesic s (S)-(+)-2-(4-isobutylphenyl)propionic acid, 2-[(2, 6-dichlorophenyl) amino]benzeneacetic acid, and o-acetylsalicylic acid. Further determin ed were the artificial sweeteners cyclamate, acesulfame-K, and sacchar in. Detection limits for the different substances were between 2.5 x 1 0(-6) and 1 x 10(-5) M.