PHOTOMETRIC DETECTION OF AMINO-CONTAINING COMPOUNDS IN CAPILLARY ISOTACHOPHORESIS BASED ON REACTION WITH COPPER(II) IONS

Some basic aspects of the photometric detection of amines, amino acids and peptides via their complexes (chelates) formed with Cu2+ ions in capillary isotachophoresis (ITP) were studied. Experiments performed i n this feasibility study were focused on the complexes of separands fo rmed on the addition of Cu'' ions to the sample solution and the catio nic mode of migration. The results suggest that only the compounds tha t form chelates with more than one ring are detectable photometrically as probably only this type of chelate did not bleed during the separa tion (migration). Detection limits for these ITP separands were in the range 10(-7)-10(-6) mol/l (30-mul sample volumes) when detection was carried out at 580 nm. ITP runs with various sample matrices indicate a high analytical selectivity of this mode of detection.