Interaction between asymmetric solutes and solvents. Diamides derived from L-valine as stationary phases in gas-liquid partition chromatography.

The resolution of enantiomers of (+/-)-a-amino acid derivatives on optically active diamides derived from L-valine, R1CONHCH[CH(CH3)2]CONHR2, as gas chromatographic stationary phases was studied. The effects of the structure of R1 and R2 in the stationary phases, the structure of the racemic a-amino acid derivatives, temperature, etc., on the separation factors are reported. In the light of these and related results, a more probable mechanism of resolution is presented.