Modelling the separation of amines by high performance liquid chromatography: I. Linear diamines NH2(CH2)nNH2 (n = 2–10) Original Research Article

This paper describes the results of a study on the HPLC retention behaviour of general formula NH2(CH2)nNH2 (n=2–10), linear diamines using strong cation exchange resin and amperometric detector. A number of eluents were used for this purpose: citric acid–Na2SO4, H2SO4–Na2SO4, HCl–NaCl, HClO4–NaClO4 and HClO4–NaClO4–CH3CN. The last eluent ensures smaller retention times (tR). The influence of the anion on tR values has been discussed. Empirical relationships between tR and capacity factors K′ with Na+ concentrations and with aliphatic chain length, in different experimental conditions, are reported. The influence of amine protonation constants on log K′ values is also discussed. Some examples of separation are reported.