STRUCTURE-RETENTION RELATIONSHIP IN THE G AS-CHROMATOGRAPHY OF HYDRAZONES

Several 2,4-dinitrophenylhydrazones (DNPHs), N,N-dialkylhydrazones (DA H) and N,N-dimethylhydrazones (DMH) were synthesized and their Kovats retention indices (I) determined. DAHs are one of the rare examples wh ere electronic structures of structural isomers differ. This is reflec ted in ?he retention relations. Retention indices for all DAHs can be estimated from the boiling points. Homomorphic factors and van der Waa ls surface area and volume (S-W, V-W) can also be used to predict rete ntion indices for both ketone and aldehyde DMHs, DAHs separately. The I-oxo values of analogous oxo compounds and molecular parameters (S-W, C=N-W bond angle, Theta, and electron density, d(C)) describe the ret ention behaviour of both classes of DMHs in a single correlation equat ion. The oxo homomorphic factors can be used for the prediction of the retention indices of DNPHs.