Effect of the stationary phase on the retention indices of dimethylformamidines, dimethylacetamidines and primary amines

Abstract

The retention indices of 70 compounds comprising series of N 1,N 1-dimethylformamidines [R x N = CH−N(CH 3) 2], N 1,N 1-dimethylacetamidines [R x N = C(CH 3)−N(CH 3) 2], primary amines (R x NH 2) and substituents R x on the nitrogen atom, were measured on a polar OV-225 column. They were then correlated with those of the same compounds measured under identical conditions on a non-polar GE SE-30 column. The changes in retention indices upon changing the polarity of the column depend on the type of substituent R x ( n-alkyl or substituted phenyl). Good linear correlations were obtained between retention indices measured on the two columns for the compounds of each series, but the slope and the intercept of the correlation line depend not only on the series of compounds, but also on the type of substituent R x at the nitrogen atom.