Resolution and identification of O-phosphoserine, O-phosphothreonine, O-phosphotyrosine, and gamma-carboxyglutamic acid as their fluorescent o-phthalaldehyde derivatives by high performance liquid chromatography.

High performance liquid chromatography was used to resolve O-phosphoserine, O-phosphothreonine, and O-phosphotyrosine as their fluorescent o-phthalaldehyde derivatives. By adjusting the buffer system, very small amounts of O-phosphothreonine could be detected and quantitated in the presence of very large amounts of O-phosphoserine. In addition, gamma-carboxyglutamic acid and glutamic acid were also separated and quantitated. Depending on the buffer used, various combinations of these amino acids could be resolved in a single run.