Separation of o-phthaldialdehyde derivatives of free amino acids from plant tissues by isocratic reverse-phase high-performance liquid chromatography

A reverse-phase high-performance liquid chromatography procedure has been developed for rapid separation and quantitation of free amino acids as o-phthaldialdehyde derivatives. A two step isocratic solvent system was used which enabled an accurate analysis at nanomole level. However, two major disadvantages to this procedure were the lack of reaction of proline and the co-elutions of threonine/glycine and tryptophan/methionine. The free amino acids in Zea mays roots were separated by using the method described.