Measurement of selected trace elements in Olea europaea L. cv. 'Sigoise'

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.

Determination of Some Major and Trace Elements in Cladodes of Barbary fig (Opuntia ficus-indica Mill.) by X-ray Fluorescence Spectrometry

Barbary fig (Opuntia ficus-indica) has attracted great attention in extensive rural agriculture for its potential agronomic, medicinal, and environmental benefits. However, there is only incomplete information about its chemical profile. Energy-dispersive X-ray fluorescence (EDXRF) spectrometry was applied to determine the concentrations of 11 major and trace elements (Br, Cr, Cu, Fe, K, Mn, P, Rb, Sr, Yb, and Zn) in cladodes of O. ficus-indica and the adjacent soil. For analytical accuracy, the standard reference materials CRM-IAEA 336 (Lichen) and CRM-NIST 1646a (Estuarine Sediment) were used. The relationships between the chemical elements were established by Pearson's correlation coefficient (r) and principal component analysis (PCA). The results show that K, P, Fe, and Mn were the dominant essential elements in O. ficus-indica cladodes; however, Br, Cr, Cu, Rb, Yb, and Zn were present at low concentrations. The cladodes showed high enrichment with K, Sr, and Br (BEF > 1), but the values of this coefficient were below 1 for the remaining elements. The PCA showed that in the O. ficus-indica cladodes, the higher concentrations of Br, K, and Sr were correlated; conversely, the highest contents of Cr, Cu, Fe, Mn, P, Rb, Yb, and Zn were retained in the soil. The present findings enabled us to determine that O. ficus-indica has a high ability to accumulate K, P, Fe, and Mn in its cladodes. Therefore, the data obtained from the analysis of this cactus will be useful for nutritional and medicinal purposes.