Analysis of Free Terpenoids in Vitis vinifera Using Solvent Assisted Flavour Evaporation and Gas Chromatography-Tandem Mass Spectrometry

The free terpenoids in the four varieties of Vitis vinifera grapes were analyzed using solvent assisted flavour evaporation (SAFE) and gas chromatography-tandem mass spectrometry (GC-MS/MS). The compounds in the grapes were macerated and extracted using vibrating extraction at constant temperature, and then the non-volatiles were removed using SAFE. The volatile compounds were concentrated with a stream of nitrogen and analyzed using GC-MS/MS. The temperature of cycle water and the flow rate of sample in the SAFE procedure were optimized. Totally, 30 terpenoids, including 10 monoterpenoids, 18 sesquiterpenoids, 1 diterpenoid, and 1 triterpenoid were identified from four varieties of grapes based on the combination of their mass spectral data from NIST05a and Kovats retention index (RI) values of the standards (RIS) and RI values reported in the literature (RIL). Twenty-eight terpenoids were detected in Cabernet Gernischt, and 16, 17, and 16 terpenoids were detected in Merlot, Cabernet Sauvignon, and Cabernet Fanc, respectively. Moreover, 17 sesquiterpenoids were identified in Cabernet Gernischt, and this was considerably higher than the number of sesquiterpenoids identified in the other three varieties. Based on semi-quantitative analysis, the concentration of monoterpenoid in Cabernet Sauvignon was the highest among the four varieties of grapes, and the concentration of sesquiterpenoid in Cabernet Gernischt was the highest. It was demonstrated that this method can be used for the qualitative and quantitative analysis of free terpenoids in grapes.