Advanced statistical evaluation of complex formation constant from electrophoretic data

A new method for the estimation of complex formation constants is presented. The method is based on electrophoretically measured effective mobilities and applied to the estimation of the complex formation constant of interaction between nitrogen heterocyclic bases and cyclodextrines. The calculation of constants is based on the linearization of the dependence between effective mobility and the cyclodextrine concentration and the application of an advanced statistical evaluation procedure. Complex formation constants 14.8 and 63.21 mol(-1) were obtained for the interaction of pyridinium and benzylaminopurinium with dimethyl-beta-cyclodextrine (DM-beta-CD), respectively. Constants in the order of magnitude 10(1)-10(2) l mol(-1) were obtained for some other purine derivatives. The proposed procedure, in connection with the mathematical software for matrix operations, is rather simple and gives much more valuable outputs than commonly used concepts. (C) 2000 Elsevier Science B.V. All rights reserved.