composition and concentration of n-alkanes in retail samples of edible oils

A range of edible oils were purchased from a variety of retail outlets and analysed for their n-alkane content. The concentrations ranged from 7 to 166 mg kg-1, the lowest being walnut oil and the highest sunflower oil. n-Alkanes with chain lengths of C27, C29 and C31 predominated in all of the plant oils except olive oil where C23, C25 and C27 were the most significant. The results of this pilot survey suggest that the n-alkanes are indigenous and that their composition may be useful in characterising a specific plant seed oil. Two of the 42 samples analysed showed markedly different alkane patterns in which profiles similar to petroleum-based sources dominated the contribution from odd carbon n-alkanes typical of seed oils.