Comparison of the relationships between the retention of dansyl derivatives of aliphatic amines and eluent composition for normal-and reversed-phase liquid-solid TLC systems

Abstract

Dansyl derivatives of four long-chain primary aliphatic amines and five secondary aliphatic amines were chromatographed in two adsorption systems: heptane+diisopropyl ether — silica and water+methanol — octadecyl cilica. In the normal-phase system RM (log k′) values were approximately linearly dependent on the log concentration of diisopropyl ether in the eluent; the separation selectivity of dansyl C8−C12 primary amines was poor. For the reversed-phase system the derivatives of both primary and secondary amines were well separated, the log k′ values being linearly dependent on per cent concentration of methanol in the eluent.