Discrimination between the oils from animals and vegetables by stable carbon isotope analysis

This paper aims to present a case study of chicken and lard oils to illustrate a novel method for discriminating between the oils from animals and vegetables by stable carbon isotope ratios. Firstly,lard and chicken oils were prepared in the laboratory. Then,their fatty acids compositions were determined by chromatography mass spectrometry( GC-MS); and the ratios of stable carbon isotopes( δ13C) of bulk oil samples and their individual fatty acids were determined by elemental analysis-isotope ratio mass spectrometry( EA-IRMS) and gas chromatography-isotope ratio mass spectrometry( GC-IRMS). The results have demonstrated that theδ13C ratios of the chicken oil are at the interval of-21. 58‰ to-18. 30‰( Fatty acids,-21. 58‰ ~-18. 30‰; and bulk oil,-19. 82‰ ~-19. 30‰),and those of the lard oil range from- 22. 16‰ to- 16. 15‰( Fatty acids,- 22. 16‰ ~- 16. 15‰; and bulk oil,-18. 70‰ ~- 16. 83‰),displaying a significant difference in theirδ13C ratios between the chicken and lard oils and vegetable oil. Therefore,we may establish a high-resolution detection method to discriminate the minor oils from animals and vegetables on the basis of the evident difference in theirδ13C ratios of oils.