Authenticity assessment of Citrus essential oils

Multidimensional Gas Chromatography (MDGC) with a chiral column in the second dimension, and Gas Chromatography Combustion Isotope Ratio Mass Spectrometry (GC-C-IRMS) represent powerful analytical tools for the quality assessment of the genuineness of Citrus essential oils. In fact, in addition to the conventional analytical methods (GC, GC-MS, HPLC, etc.) these techniques can be applied to different botanical sources. Enantio MDGC is the most powerful tool to determine with high accuracy the enantiomeric excess (EE) and the isotopic ratio (delta 13C) of selected volatile components (monoterpene and sesquiterpene hydrocarbons, aldehydes and alcohols) in numerous samples of authentic cold-pressed and distilled Citrus oils, of different geographic origin and commercial oils. The results of the two analytical approaches are compared. The genuineness assessment was accomplished based on the range of authenticity determined by the EE and delta 13C from genuine samples of secure origin. The results attained are often complementary, thus providing additional information for the evaluation of natural, natural-identical or synthetic mixtures. Useful information on the natural occurrence of chiral compounds and on the naturally occurring delta 13C values in authentic oils are provided.