As a wine ages altered sensory properties lead to changes in perceived quality and value. One major chemical component observed to change significantly during this aging process is the tannin composition, and in particular the pigmented tannin composition. Using normal-phase nano-scale liquid chromatography with quadrupole time of flight (QToF) tandem mass spectroscopy, two vintages of Cabernet Sauvignon wine from the same winery have been investigated as to the compositional differences in their pigmented tannin fractions. The aged wine demonstrates much greater structural diversity and a range of compounds eluting later under normal phase conditions, while the younger wine contains fewer observed ion peaks and much different chromatography. Several hundred molecular features are observable and, as expected, chromatographic progression to higher molecular weights at longer retention times has been observed. Many signals could be tentatively assigned to known and anticipated pigmented tannin and phenolic compounds, though sufficient fragmentation for isomeric discrimination will require further investigation. Chromatography displays a high degree of resolution in aged wines separating many of the known compound classes as well as resolving a great number of unknown compounds.

Pigmented tannin by polar chromatography tandem MS for identification of candidate molecular features

255th National Meeting (2018)

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