NONAQUEOUS CAPILLARY-ZONE-ELECTROPHORESIS USING POLYETHYLENE-GLYCOL AS A MATRIX AGENT

Non-aqueous capillary zone electrophoresis in acetonitrile containing polyethylene glycol as a matrix agent was investigated. Separation of benzoate anions as model samples were optimized by a control of the co ncentration and the selection of the chain length of polyethylene glyc ol. Base Line resolution was attained in the presence of 15% (w/v) pol yethylene glycol 4000 for the benzoates used. In acetonitrile, polyeth ylene glycol works as a hydrogen-bonding donor and acceptor; the termi nal hydroxyl groups serve as a donor toward the dissociated carboxyl g roups of the benzoates, while the ether oxygen atoms serve as an accep tor toward the hydrogen-donating substituents of the benzoates. This p roperty of polyethylene glycol is in marked contrast with that observe d in aqueous phase, where polyethylene glycol works predominantly as j ust a hydrogen acceptor. Quantitative analysis of the interaction is p resented. (C) 1998 Elsevier Science B.V. All rights reserved.