Comparison of Sr, Pb, and U isotopic compositions of bottled mineral waters produced in Romania and other European countries for authentication

Abstract

Purpose We analyzed the isotopic composition of four elements, Sr, Pb, U, and Mg, in bottled natural mineral waters and medicinal waters. We aimed to develop a robust geochemistry-based analytical operation procedure to authenticate mineral waters. Methods A simplified sample preparation method using ion exchange and corona-ether-based chromatographic workflow was developed together with the optimization of HR-ICP-MS (NU-Attom ES) measurement methods. Findings: We found a large diversity in Pb and Sr isotope ratios and the shift of 234U/235U isotopic composition of samples compared to in laboratory reference material derived from NIST2710 SRM. The resolving power of 26Mg/24Mg was limited. 4 samples out of the 25 differed, barely significantly, from the average of all samples. The three Pb isotopic parameters correlated with each other but not all the variations could be explained by one single parameter. Sr, Mg, and U signatures were independent of each other, and Pb isotopic signatures, PCA could not reduce the dimensionality of the data without a large information loss. Using isotopic identification parameters directly, all the different aquifers could be distinguished. The parameter values did not change in a 4-years interval. Originality: We report the first multi-isotopic, ICP-MS-based method for food authentication, which is readily applicable in a commercial framework.