Trace Elements Analysis of Tunisian and European Extra Virgin Olive Oils by ICP-MS and Chemometrics for Geographical Discrimination

The aim of this study was to investigate the levels of trace elements in olive oils from different locations and their use for geographical authentication. Concentrations of seventeen elements were determined in a total of 42 olive oils from Tunisia, Spain (Basque country), and southern France, and in nine soil samples from Tunisia by quadrupole inductively plasma mass spectrometry. The compilation of appropriate techniques integrated into the analytical procedure achieved a precision (RSD) between 2% and 15% and low limits of detection (between 0.0002 and 0.313 µg kg−1). The accuracy of the analytical method applied for olive oil analysis was evaluated using SRM NIST 2387 Peanut butter. The recoveries obtained after microwave-assisted digestion for the certified elements ranged between 86% and 102%. Concentrations of non-certified elements (V, Cr, Co, Ni, Ba, Rb, Sr, Cd, Pb, and As) were presented. The use of Pearson correlation applied on paired Tunisian oil/soil samples has shown that several elements (Mg, Mn, Ni, and Sr) were significantly correlated. The multivariate statistics using principal component analysis have successfully discriminated against three studied origins. The most significant variables were the elemental concentrations of Cu, Cr, Fe, Mn, Sr, V, and Zn. This study shows the potential of applying trace elements profiles for olive oil geographical discrimination.This research was funded by European Project TunTwin from the Horizon 2020 Framework program of the European Union under grant No. 952306. It was also funded by the French ANR EquiPex MARSS project with a contribution of the METROFOOD ESFRI project. This work was partially supported by the Euskadi/Nouvelle Aquitaine/Navarra Eurorregion through the research project ISOTOPO (with agreement no. 2020/3). The financial support of a Ph.D. grant for Emna G. Nasr has been provided by the “Excellence Eiffel” scholarship of Campus France, the European project “TunTwin” and the scholarship “bourse d’alternance” of University Tunis El Manar, Ministry of Higher Education and Scientific Research in Tunisia

Determination of 87Sr/86Sr isotopic ratio in olive oil and pomace using multicollector-ICPMS; analysis of pomace residues as a simpler approach for determination of 87Sr/86Sr ratio in olive oil with low Sr content

This study presents an analytical procedure for measuring the 87Sr/86Sr isotopic ratio in olive oil and pomace using multicollector-inductively coupled mass spectrometry (MC-ICPMS). The developed method combines liquid-liquid extraction with an acid solution and degradation of organic residues in the extract by dry ashing and oxidation by H2O2 and HNO3. The method enabled 87Sr/86Sr ratios to be obtained in olive oil with Sr content as low as 0.2 ng/g, with a precision of 54 ppm. The method’s validity was confirmed by an interlaboratory comparison using NIST SRM 2387, providing the first data on its elemental Sr (2380 ± 230 ng/g ; n = 10), and 87Sr/86Sr isotopic composition (0.70908 ± 0.00004 ; n = 14). The procedure was applied to olive oil and pomace samples, showing that they have an identical 87Sr/86Sr ratio, which was consistent with that determined in soils from the same orchards. The results thus revealed that Sr isotopic ratios of olive oil and pomace can both be used in geographical traceability studies of olive oil, which means that, instead of processing large volume of oil, characteristic 87Sr/86Sr signatures of olive oil can be more easily obtained by analyzing small quantities of pomace obtained by centrifuging the oil

Multi-element and multi-isotopic profiles of Port and Douro wines as tracers for authenticity

Port and Douro wines are produced in the Douro Demarcated Region using different wine making processes. This works aims at evaluating the influence of the geographical origin and the wine making process in their multielement (Li, Be, B, Al, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sn, Tl, Pb, Fe, Mg, P, Ca, Na, K) and isotopic compositions (87Sr/86Sr, δ11B, xPb/yPb, δ18O). Fifteen samples of each were analysed. ANOVA identified significant differences for Ca, Na, Rb, Zn, Cu, Cr, Se, 206Pb/204Pb, 207Pb/204Pb, 206Pb/207Pb and δ11B. PCA revealed that Cr, Se and Cu are the main contributors for discrimination by type of wine. 87Sr/86Sr and δ18O are region specific and not influenced by the winemaking process or storage. Thus, make good natural tracers for geographical origin of this region. HCA suggested a common profile in Port and Douro in white wines, for Sr and K, which should be further investigated.Highlights: Inorganic analysis was used to study the geographical authenticity of wines; Port and Douro wines have different inorganic signatures; The wine making process influences the multielement fingerprint; Cr, Se and Cu are the main contributors for discrimination by type of wine; 87Sr/86Sr and δ18O are specific to the region.The scientific work was funded by project METROFOOD-PP from the European Union’s Horizon 2020 research and innovation program under Grant Agreement No 871083 and project MASSTWIN from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 692241, and the MARSS EquiPex Project The authors acknowledge Fundação para a Ciência e a Tecnologia (FCT - MCTES) for its financial support via the project UIDB/00667/2020info:eu-repo/semantics/publishedVersio