COMPARISON OF THE PERFORMANCE OF RP C-18 ON SILICA AND POLYMERIC SUPPORTS FOR THE LIQUID-CHROMATOGRAPHIC SEPARATION OF METAL AMINO-ACID COMPLEXES WITH POSTCOLUMN DERIVATIZATION

On the basis of previous studies on the behaviour of metal-amino acid complexes with reversed-phase C18 stationary phases, which can provide useful information on metal speciation, the performances of different silica and polymeric supports were compared. Both the pH stability of the stationary phase and the presence of free OH groups in the suppor t material, with ion-exchange effects, were considered. To determine a mino-acids more rapidly and with higher reproducibility and sensitivit y, a postcolumn derivatization procedure is also described. The result s indicate that the use of a reversed phase on a non-conventional sili ca support, with postcolumn derivatization, seems to be necessary to d etermine metal-amino acid complexes.