Performance of 2-Amino Tetraphenyl Porphyrin as Stationary Phase in RP-HPLC of Amino Acids

The search for new stationary phases has been one of the predominant concerns in high performance liquid chromatography (HPLC) in order to achieve better resolutions, longer column lives, and reduce the time of analysis. A chromatographic packing for separation of underivatized amino acids (AAs) were prepared by dynamically coating 2-amino tetraphenyl prophyrin (atpp) on a C-18 reversed-phase packing and its properties were examined. The retention characteristics of 20 AAs forming the building blocks of proteins were investigated on the atpp coated C-18 column at pH 7. Results obtained seem to confirm a mixed mechanism of retention involving the hydrophobic interaction between the aromatic porphyrin macrocycle and some of the AAs, p-p interaction between the p-electrons of the porphyrin macrocycle and the p-electrons of analyte, and the hydrogen bonding interactions between Ass and the porphyrin nitrogens.