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 aliphatic model substances, respectively, were detected in capillary electrophoresis with all-solid-state ion-selective electrodes. The sensitivity for these compounds is a function of their lipophilicity. The signal detected is generally greater for molecules with a larger organic part. The utility of the method is further demonstrated by the detection of a group of aromatic compounds in the form of the anionic analgesics (S)-(+)-2-(4-isobutylphenyl)propionic acid, 2-[(2, 6-dichlorophenyl)amino]benzeneacetic acid, and o-acetylsalicylic acid. Further determined were the artificial sweeteners cyclamate, acesulfame-K, and saccharin. Detection limits for the different substances were between 2.5 x 10(-6) and 1 x 10(-5) M.