in the Abruzzo and Marche regions has grown exponentially: the global area cultivated with _Pecorino_ grapes in Abruzzo, for instance, has increased from 22 to 1080 ha in the years between 2000 and 2015, which is reputed as the fastest growth worldwide in the cultivation of a grape variety. _Passerina_ white grape is also an ancient variety belonging to the wider _Trebbiano_ family. Traditionally cultivated in the border area between the Abruzzo and Marche regions, _Passerina_, like the _Pecorino_ variety, was replaced by the more-productive _Trebbiano Abruzzese_ and _Trebbiano Toscano_ varieties since 1960-1970 and was only recently rediscovered. The global surface of _Passerina_ vineyards in Abruzzo increased, in fact, from 85 ha in 2005 to 369 ha in 2015. Wine is often the subject of commercial fraud [2; 3; 4]; for instance, water, sugars, alcohol, sweeteners, and flavoring agents can be added illegally. Misrepresentation of the cultivar and the geographical origin is another form of fraud more difficult to uncover compared to chemical adulteration, and several cases have been documented in the last decades. In Europe, most of the wines of high quality and high commercial value are strictly linked to the production area and specific method of production, and, according to the EU regulations, are certified by Protected Designation of Origin (PDO), Protected Geographical Indication (PGI), or Traditional Speciality Guaranteed (TSG) marks. Several PDO wines are also produced with a single grape variety (mono-varietal wines). In this scenario, reliable analytical methods able to determine wine authenticity and compliance with the origin/variety denomination are essential tools for the safeguarding of consumers from fraud and for ensuring honest market competitiveness. For this purpose, specific analytical techniques based on categories of chemical species (volatiles, polyphenols [2; 5], organic acids [6], trace elements [7; 8], and isotopes [9], for instance) or spectroscopic methods [10; 11; 12] have been proposed. In this context, metabolomics plays an important role. Organic acids, phenolic compounds, and volatile components, in particular--whose content in wines is influenced by different factors, such as grape variety, geographical origin, vintage, and winemaking process--are not only powerful geographical/varietal markers but also affect the wine's taste and aroma. Regardless of the analytical technique applied to characterize the samples, chemical information provided by both targeted or untargeted responses needs to be handled by suitable chemometric tools to differentiate or authenticate wines [4; 13; 14], for instance: Principal Component Analysis, Linear Discriminant Analysis (LDA), Partial Least Squares Discriminant Analysis (PLS-DA), or Soft Independent Modelling of Class Analogy (SIMCA). Because of the complexity of wine composition, application of a single analytical technique may be inadequate, especially in the discrimination of varieties produced with grapes of the same family and/or cultivated  
Figure 1: Location of the cultivation sites of the investigated wines within the four provinces, L’Aquila (AQ), Teramo (TE), Pescara (PE) and Chieti (CH), of the Abruzzo region. in close territories. On the other hand, data-fusion approaches, which can combine information arising from data of different natures in a single classification model, are expected to perform better than individual-block analyses [15]. Nevertheless, it is less common to find papers where data from different analytical platforms are jointly processed to classify wines according to their geographical or botanical origin [16; 17; 18; 19; 20; 21]. In the present work, we analyzed certified mono-varietal wines produced with _Trebbiano d'Abruzzo, Pecorino_ or _Passerina_ grapes in specific territories with well-established reputations for their winemaking tradition, covering as much as possible the four provinces of Abruzzo region (Figure 1), and attempted a classification of the wines on a varietal basis.