CORRELATION FREE-SOLUTION CAPILLARY ELECTROPHORESIS MIGRATION TIMES OF SMALL PEPTIDES WITH PHYSICOCHEMICAL PROPERTIES

A series of small peptides containing varying degree of charge and size was used to study the effects of physicochemical properties on migration in free-solution capillary electrophoresis (FSCE). A semiempirical relationship between migration time under acidic conditions and the square root of molecular weight divided by the quantity of the number of the positively ionizable groups has been established. The ionization of the carboxyl terminal group in the polypeptides is negligible under acidic conditions. The relationship developed from this work has been used for the prediction of migration parameters in free solution capillary electrophoresis.