Separation of amino acids on reversed-phase columns as their copper(II) complexes

Abstract

We report the separation of amino acids on reversed-phase columns using aqueous mobile phases containing copper ions. Cu(II) forms complexes with the amino acids and therefore influences their retention times. More importantly the Cu—amino acid complex absorbs UV radiation with λ max around 230 nm. Thus the solutes can be detected at relatively long wavelengths. The linearity of the detector signal and the detection limits were studied. Ssamples as small as 10 ng per 10 μI can be detected and the useful range of detection is oer four orders of magnitude. The effects of the pH of the mobile phase were also studied: retention increases with pH, at least over the range investigated.