Characterization of volatile fractions in green mate and mate leaves (Ilex paraguariensis A. St. Hil.) by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC/TOFMS)

• First report detailing the differences between fresh mate leaf and green mate using GC × GC.
• 157 and 291 compounds tentatively identified in fresh leaf and green mate, respectively.
• 168 compounds reported for the first time in green mate.
• Hazardous contaminants (hydrocarbons and PAHs) were identified in green mate.
• Most detailed characterization of Ilex paraguariensis volatile profile reported.

Ilex paraguariensis A. St. Hil. is well known due to its great economic and social value. However, investigations detailing the differences between the volatile chemical profiles of fresh mate leaves and their processed product, green mate, remain largely neglected. Taking these considerations into account, this study aimed to obtain a deeper understanding of the constituents of fresh mate leaf and green mate essential oils (EOs). Toward this purpose, GC × GC/TOFMS and retention indices were used to improve the chemical characterization of these EOs. A total of 157 and 291 compounds were tentatively identified in fresh leaf and green mate EOs, respectively (168 of which are reported for the first time in green mate). The major constituents of the fresh leaf EOs were found to be 3-allylguaiacol (28.51%), linalool (17.61%), and methyl salicylate (5.36%), while those of green mate were 2,6-dimethyl-1,7-octadien-3-ol (9.77%), linalool (5.58%), and α-terpineol (4.67%). Furthermore, hazardous contaminants such as hydrocarbon isomers and PAHs (in particular, alkylated PAHs) were tentatively identified in green mate. The results represent the most detailed characterization of these EOs reported to data and suggest the need to use smokeless methods in mate processing.