Retention behavior of conjugated and isolated n-alkadienes. Identification of n-nona- and n-decadienes by capillary gas chromatography using structure-retention correlations and mass spectrometry

The isomerization products of n-C8---C10 a,¿-alkadienes were separated on a high-efficiency squalane column (195 m × 0.25 mm I.D.) with 500,000 effective plates. Of the 102 possible n-C8---C10 dienes with isolated and conjugated double bonds, only nine groups of isomers were not separated. All isomers, except those with cumulated double bonds, were identified (23 octadienes, 33 nonadienes and 46 decadienes). The n-octadienes were identified by matching measured and published retention data. Because of the lack of standards, retention data and mass spectra of n-nona- and decadienes, and because the previously reported identification method for n-dienes up to C8 was succesful, the problem of the identification of C9---C10 n-alkadienes was solved similarly by using structure-retention correlations and combined capillary gas chromatography-mass spectrometry. Based on these results, the retention behaviour of the conjugated and isolated n-alkadienes, on squalane stationary phase, is generalized