## 5 Conclusions  
The use of GC-IT-MS and UPLC-DAD proved to be a powerful combination for studying the inter-varietal diversity of typical volatile and phenolic profiles of Croatian EVOOs, respectively. Each of the investigated monovarietal EVOO displayed unique volatile aroma and phenol composition. The qualitative and quantitative chromatographic data was useful for tentative elucidation of some of the perceived sensory attributes including the variety-typical ones, which though has to be taken with caution due to the extreme complexity of the established chemical profiles with the majority of volatiles with still unknown sensory relevance. Many potential varietal markers were extracted by uni- and multivariate statistical analysis despite high intra-varietal heterogeneity. It was demonstrated that volatiles and phenols from all the investigated chemical classes can be useful for this purpose. Many of the volatile compounds which turned out to have a notable discrimination power were (tentatively) identified for the first time in EVOO, or were generally neglected in previous studies, especially from sensorial point of view. In fact, only in a few cases were the major LOX compounds, studied most extensively among the volatiles up to date, sufficient for a robust varietal differentiation in this work. This indicates a large potential of the untargeted fingerprinting approach for EVOO characterization, differentiation, and authentication studies. The number of the extracted robust varietal markers among the investigated chemical compounds largely exceeded the number of typical sensory attributes useful to differentiate monovarietal EVOOs. It is reasonable to conclude that the approach which comprises GC-IT-MS and UPLC-DAD analytical techniques may provide additional objective information about varietal origin which successfully complement those obtained by sensory analysis. Probably the best example for this is the case of Rosinjola EVOO which was relatively similar and hardly distinguishable from that of Buza variety based solely on the sensory analysis, but was characterized by many exclusive chemical markers among benzenoid and furanoid volatiles which discriminated this EVOO rather successfully. The results obtained in this study could certainly be useful for improving the quality management and control in the production of Croatian monovarietal/PDO EVOO. These findings could contribute to strengthening their PDO identities and position on the market, and could be especially useful for discriminating EVOOs of Croatian native varieties from the world famous Leccino variety. The following are available online at [[http://www.mdpi.com/2304-8158/8/11/565/s1](http://www.mdpi.com/2304-8158/8/11/565/s1)]([http://www.mdpi.com/2304-8158/8/11/565/s1](http://www.mdpi.com/2304-8158/8/11/565/s1)), Table S1: Climate parameters in the Istria and Dalmatia regions of Croatia in 2015, Table S2: Standardized coefficients of the variables selected for the differentiation of monovarietal Buza, Istarska jbeliac, Rosinjola, Oblica, Lastovka, and Leccino extra virgin olive oils on the first three discriminant functions obtained by stepwise linear discriminant analysis, and the percentage of correct classification at each step, Table S3: The intensities and scores of the sensory attributes perceived in monovarietal extra virgin olive oils produced from Buza, Istarska bejelica, Rosinjola, Oblica, Lastovka, and Leccino varieties in Croatia. Conceptualization, I.L. ; Methodology, I.L. ; Formal analysis, I.L., M.L., M.Z., M.K., S.G., K.B.B. ; Resources, I.L., M.L., K.B.B. ; Data curation, I.L., M.L., K.B.B. ; Writing--original draft preparation, I.L. ; Writing--review and editing, I.L., M.L., K.B.B. ; Supervision, I.L. ; Project administration, I.L. ; Funding acquisition, I.L. This research was funded by Croatian Science Foundation grant number UIP-2014-09-1194. The authors would like to thank olive oil producers from Istria and Dalmatia (Croatia, EU) for donating the samples of extra virgin olive oils, and [PERSON] M.Sc.