Similarity of binary mixed aqueous-organic solvents for capillary zone electrophoresis based on the ionic mobility of substituted benzoates evaluatedby cluster analysis and information theory

The similarity of solvents used for buffering background electrolytes in ca pillary zone electrophoresis is evaluated by two chemometric techniques: cl uster analysis and information theory. The solvents are water and binary aq ueous-organic mixtures of methanol, ethanol, l-propanol, and acetonitrile, respectively, with concentrations up to 80% v/v of the organic constituent. The electrophoretic properties of the solvents are described by the actual mobilities of 26 aromatic anions, hydroxy-, methyl-, nitro-, and chloro-su bstituted benzoates. Cluster analysis results in two main clusters, the one consisting of the alcoholic systems, the other of water and the mixtures w ith acetonitrile. The information content of the single solvent systems ran ges up to 4 bit for the acetonitrilic solvent. The similarity of the system s is evaluated by information theory from the loss of information content d ue to the correlation between the mobility data in the particular solvents. (C) 1999 John Wiley & Sons, Inc.