Reversed-phase HPLC of peptides with tetraphenylporphyrin-based stationary phase and potentiometric detection with a copper electrode

The retention of selected amino acids and simple peptides has been investigated using columns with stationary phases with immobilized [5-(p-carboxyphenyl)-10,15,20-tri-phenyl]porphyrin and zinc(II) ion as coordination center. The use of potentiometry with a metallic copper electrode provides an especially sensitive detection of peptides containing histidine. The retention mechanism includes both interactions between the aromatic moieties of the solute molecule and immobilized metalloporphyrin and a complexation interaction between solutes and the metallic center of the metalloporphyrin.