Facile gas chromatography-tandem mass spectrometry stable isotope dilution method for the quantification of sesquiterpenes in grape.

Sesquiterpenes are a widespread class of compounds of increasing interest found in grapes and wines, amongst many other natural sources. Due to a lack of standards and the complexity of the mass spectra fragmentation, accurate quantification of these low concentration compounds had not previously been accomplished. The current paper presents a new method for the concurrent quantification of several sesquiterpenes. The multivariate method optimisation is presented. Synthesised isotopic standards were utilised in conjunction with solid phase microextraction (SPME) and gas chromatography-tandem mass spectrometry (GC-MS/MS) to perform a standard isotope dilution assay (SIDA). The method was successfully applied to several grape must samples of four different cultivar. To the best of our knowledge this was the first time some of these sesquiterpenes were quantified in grape.