Tracing the Geographical Origin of Tobacco at Two Spatial Scales by Stable Isotope and Element Analyses with Chemometrics

Abstract

Tobacco is one of the most widespread cash crops in the world, as such it is subject to smuggling and illegal sales. There is currently no authentication of the geographical origin of tobacco in China. Here we identified stable isotopes and elements from 136 tobacco samples at two spatial scales. 87/86Sr, Cs, K, and δ13C showed significant differences at provincial-scale, while Sr, Pb, and Se were important parameters at municipal-scale. The heat map we constructed of municipal-scale provides a preliminary assessment of tobacco origins, with cluster classification similar to geographic grouping. Using OPLS-DA modeling, the discriminant accuracy was 99.2% for provincial scale and 97.6% for municipal scale. Moreover, rankings of importance of variables differed depending on the spatial scale of the evaluation. This study establishes the first traceability fingerprints dataset of tobacco and represents a promising tool to identify the geographical origin of tobacco.

Keywords: Geographical origin, Stable isotopes, Elements, OPLS-DA modeling, Tobacco