Comprehensive investigation of lactones and furanones in icewines and dry wines using gas chromatography-triple quadrupole mass spectrometry

A number of lactones and furanones associated with pleasant odorants play a vital role in grape and wine aroma profiles. However, they are usually present at trace levels and are particularly challenging to measure. In this work, an optimized method based on solid-phase extraction (SPE) coupled with gas chromatography-triple quadrupole mass spectrometry (GC-QqQ-MS/MS) was developed for simultaneous determination of 14 lactones and 3 furanones. The validation was carried out using different types of wine as matrices, and satisfactory linearity, sensitivity, trueness and precision were confirmed. Furaneol and sotolon showed significantly lower limits of detection (LODs) in three real wines compared to model wine due to the matrix effect. Furthermore, the method was successfully applied to investigate the concentration range of lactones and furanones in several icewines, dry red and white wines. Icewines contained higher concentrations of most lactones and furanones compared with dry red and white wines. Partial least squares-discriminate analysis (PLS-DA) also indicated that γ-hexa-, γ-octa-, γ-nona-, γ-deca-, δ-hexa-, and δ-decalactone, as well as 5,6-dihydro-6-pentyl-2H-pyran-2-one (C10 massoia lactone), sotolon and homofuraneol contributed greatly to the discrimination between icewines and dry wines. Moreover, the calculation of odor activity value (OAV) suggested that γ-octa-, γ-nona-, and γ-decalactone, as well as furaneol and homofuraneol contributed greatest to the aroma of icewines.