Multidimensional gas chromatography in essential oil analysis. Part 2: Application to characterisation and identification

Multidimensional gas chromatography (MDGC) has already been established as a method which enables the separation and identification of compounds which co-elute in conventional gas chromatography, as well as obtaining more accurate qualitative and quantitative characterisation of compounds of low abundance. In the first part of this review mini-series, we discussed advances in technical aspects of the MDGC systems for essential oil (EO) analysis (Lebanov et al. in Chromatographia, 2018). This second part critically discusses the application of MDGC to the process of characterisation and authentication of EOs, illustrating the benefits of the increased separation power to achieve the resolution of the full chemical profile of EOs, as well as the identification of chiral compounds and aroma analysis. Papers focused on MDGC in essential oil analysis are reviewed from the perspective of the influence of different variables, such as species, chemotype, plant organ, environmental conditions, plant age, and distillation processes, on the chemical profile of the essential oil. Special attention is placed on qualitative and quantitative aspects of EO analysis by MDGC. One section of this review is dedicated to data analysis and the application of multivariate statistical analysis in the process of essential oil authentication.