Separation of Cobalt (III) Bis(ethylenediamine) Amino Acid Complexes by Reversed Phase HPLC

Abstract

Methods for the rapid analysis of amino acid cobalt (III) bis(ethylenediamine) complexes by reversed phase high performance liquid chromatography (HPLC) are described with mobile phases containing the pairing ions, p-toluenesulphonate and hexanesulphonate. Under these conditions, the amino acid cobalt (III) bis(ethylenediamine) complexes elute in order of the relative hydrophobicities of the parent amino acids which suggests that the amino acid side chain makes a significant contribution to the retention mechanism. At high sample loadings, these complexes shows a concentration dependent peak splitting effect divergent to that normally experienced with inadequate buffering capacity of the pairing ion reagent.