The Determination of ¹¹B/¹⁰B and ⁸⁷Sr/⁸⁶Sr Isotope Ratios by Quadrupole-Based ICP-MS for the Fingerprinting of South African Wine

Abstract

The ¹¹B/¹⁰B and ⁸⁷Sr/⁸⁶Sr isotope ratios in wines and soils of four major South African wine-producing regions have been determined by quadrupole-based ICP-MSin order to establish a fingerprint for origin verification of the wines. The ¹¹B/¹⁰B isotope ratio was found to be a useful tool to distinguish among the wines of the selected wine regions. In addition, the use of B isotope ratios together with elemental concentrations of selected indicator elements as independent variables in a linear discriminant analysis procedure was shown to be a highly successful method to classify wine according to geographical origin. A good correlation between the B and Sr isotope ratios in wine and its provenance soil was found. Both wine and soil samples were prepared using microwave-assisted digestion followed by the isolation of boron and strontium from the sample matrix through element-specific ion exchange. Isotope ratio measurements with good precision, ~0.1 % RSD, for both boron and strontium have been obtained. The ⁸⁷Sr/⁸⁶Sr ratio showed limited potential as an indicator of provenance in the wine-producing regions included in this study, since the wines of only one region could be distinguished from the others.

Keywords: Boron Isotope Ratio, Strontium Isotope Ratio, ICP-MS, Wine Analysis, Fingerprinting, Provenance Determination