A simple and rapid method of quantitative analysis of phosphoamino acids by high-performance liquid chromatography.

A high-performance liquid chromatographic system for the separation of nonradiolabeled phosphoamino acids and orthophosphate by ion-pair reverse-phase chromatography has been developed. By the use of low-ionic-strength phthalate buffers at pH 6.3, the phosphoamino acids can be visualized by virtue of this uv-active eluant. The technique is sensitive to 200 pmol of phosphoamino acid and has been shown to be directly applicable to the analysis of isolated phosphoproteins.