ABSTRACT
The separation of amines on a column of cation-exchange resin loaded with copper ions is the archetype of Ligand exchange chromatography (LEC). H. F. Walton and co-workers, as well as other research groups, published a series of papers dealing with practical applications of LEC for the separation of mixtures of aliphatic and aromatic amines and diamines, hydrazines, aziridines, alkanolamines, amino sugars, nucleic bases. Aromatic amines have been separated on several metal-exchanger combinations. Aromatic amines have also been separated in the gas phase. Certain diamines and polyamines occur widely in plant and animal tissue and are of medical interest. Alkanolamines are polar and hydrophilic with low volatility, and hard to analyze by Gas chromatography. LEC gives the best separation of mono- and diethanolamine. The LEC of simple aliphatic amines is of little practical interest, for these compounds can be analysed very effectively by gas chromatography, but the elution orders show clearly the effect of steric hindrance about the nitrogen atom.
