Reversed-phase high performance liquid chromatographic (RPHPLC)
determination of amino-acids with on-line pre-column
ortho-phthalaldehyde (OPA) derivatization and fluorescence
detection is rapid and sensitive. However, high-performance ionexchange
chromatography (HP-IEC) with post-column ninhydrine
reaction is the most widely used amino-acid (AA) assay for
biological samples. These two methods have been compared for the
determination of individual plasma AA concentrations