87Sr/86Sr ratio in vineyard soils from Portuguese denominations of origin and its potential for origin authentication

Abstract

Aim: The control of geographical origin is one of the most challenging topics regarding wine authenticity. The aim of the present study was to assess the 87Sr/86Sr ratio of vineyard soils from Portuguese Denominations of Origin (DO) and evaluate its suitability as a tool for origin authentication. Methods and results: An analytical protocol was optimized (chromatographic separation of Sr and Rb, followed by inductively coupled plasma-mass spectrometry (ICP-MS) analysis) for 87Sr/86Sr isotopic ratio determination in soilwine system. The 87Sr/86Sr ratios of soils from four vineyards located in three Portuguese DO (Dão, Óbidos and Palmela), established on distinct soil types, were determined. Significant differences were found between soils of different DO regions. The soil in the Dão DO, developed on granites, showed a statistically higher 87Sr/86Sr ratio than the other soils, which were developed on sedimentary formations. Conclusion: The results show clearly that 87Sr/86Sr ratio may represent a suitable fingerprint for these Portuguese DO. Significance and impact of the study: This study highlights the relevance of setting up an international databank of 87Sr/86Sr values for use for geographical identification and authentication.