Insights from selected ion flow tube mass spectrometry (SIFT-MS) and chemometrics applied to the quick discrimination of grapevine varieties

Abstract

Selected Ion Flow Tube Mass Spectrometry (SIFT-MS) is an innovative analytical method based on soft chemical ionization to analyze thecomposition in volatile compounds of a gas phase. In this research, we propose a quick way to access the aromatic potential of grape varieties through a scan of their volatilome by SIFT-MS and chemometrics approaches. During 3 sampling campaigns carried out in September 2020, we collected berries from 21 grapes varieties planted in a germplasm collection. For each variety, three replicate samples of 50g were gently crushed and put in 1L Schott bottles that were directly connected to a SIFT-MS equipment to analyse the headspace. Analytes injected in the SIFT-MS were ionized with 3 different reagent ions (H3O+, O2+. and NO+) to generate increased molecular fragmentation data (2). M/z data/ratios were first analysed with XlStats software (Addinsoft, Paris, France) using a one-way ANOVA treatment to determine the ions that enabled to discriminate the grape varieties. Then based on these discriminating ions, Principal Component Analysis (PCAs) were constructed and Hierarchical Clustering Analysis (HCA) ensued to create similarity groups. Finally, an ANOVA treatment was conducted to determine significant differencies in ions abondances between groups (1). For each homogenous group, a cultivar was selected to perform Headspace-Solid Phase Microextraction (HS-SPME) followed by Gas Chromatography-Mass Spectrometry (GC-MS) analyzes to connect SIFT-MS data to the composition in volatile compounds (3). Grape varieties were easily distinguishable based only on their SIFT-MS volatilome scan. The technique was able to distinguish high and low aroma compounds producers, and to organise grape varieties by similarity. We proved that SIFT-MS is a really quick and interesting tool with potential application in various fieds of viticulture such as phenotyping of grape varieties based on their volatile composition or studying of the impact of viticultural practices on the grape aroma composition using an easy to implement untargeted approach.