M. Gorgenyi et al., PREDICTION OF GAS-CHROMATOGRAPHIC RETENTION INDEXES OF 2,4-DINITROPHENYLHYDRAZONES, Journal of chromatography, 693(1), 1995, pp. 181-185
Kovats retention indices (I) of C-1-C-8 aldehydes and ketones and thei
r 2,4-dinitrophenylhydrazones (DNPHs) were determined. The temperature
gradient of the retention indices of keto hydrazones is higher than t
hat of aldehyde hydrazones, hence the separation of certain co-eluting
hydrazones is possible by changing the elution temperature. The reten
tion index difference between the E- and Z-isomers increases with incr
easing asymmetry in the groups attached to the hydrate carbon atom. Th
e slope a in the equation I-DNPH = aI(oxo), + b is near unity for not
heavily branched aldehyde DNPHs, whereas for keto E-isomers it is less
than unity and changes with the structure.