Capillary electrochromatographic separation of aromatic amino acids possessing peptides using porphyrin derivatives as the inner wall modifiers

摘要

Two different porphyrin derivatives (H_2 TPP(m-OPh)_4 and Rh(III)Tpp(m-OPh)_4 were investigated with respect to their capability to help resolution of five model aromatic peptides in capillary electrophoresis/open tubular capillary electrochromatography. Though the main separation mechanism was preferentially based on the ionic properties of the separated analytes, involvement of particularly H_2TPP(m-OPh)_4-peptide interactions at alkaline pH (8.0) was clearly demonstrated. In combination with Tris-phosphate buffer, a speed up of the separation was observed at pH 2.25 (particularly if Rh(III)TPP(m-OPh)_4 was used as capillary coating); in spite of the speed up of the separation the selectivity of the system was sufficient and resulted in a complete separation of the five model peptides. It can be expected that Rh(III)TPP(m-OPh)_4 capillary coating in combination with Tris-phosphate buffer can be generally used for a considerable speeding up of lengthy separations of peptides in acidic media with some decrease in the separation power of the system.