The determination and application of (87) Sr/(86) Sr ratio in verifying geographical origin of wheat.

As 87 Sr/86 Sr ratio plays a significant role in authenticating the geographical origin of foodstuff, it is important to identify where the 87 Sr/86 Sr signature in food comes from, and the methods of 87 Sr/86 Sr ratio analysis in food and environmental samples. Wheat with three genotypes, soil and groundwater samples were collected from three regions of China during harvest time of 2014. The 87 Sr/86 Sr ratios in the samples were determined by thermal ionization mass spectrometer in order to investigate the possible source of 87 Sr/86 Sr in wheat, and the concentrations of Rb and Sr in wheat and soils were also detected by inductively coupled plasma mass spectrometry and combined with 87 Sr/86 Sr ratio in order to trace the geographical origin of wheat. The 87 Sr/86 Sr ratio, the contents Rb and Sr, and Rb/Sr ratio of wheat and soil samples showed significant differences among three regions. The 87 Sr/86 Sr ratios and the concentrations of Rb and Sr in soils were higher than those in corresponding wheat. The 87 Sr/86 Sr ratio in wheat was identical to that corresponding soil NH4 NO3 extracts (labile fraction of soil) and groundwater. Wheat uptake more Rb than Sr. 3D distribution of 87 Sr/86 Sr, Rb and Sr could identify wheat samples from different regions clearly. The 87 Sr/86 Sr ratio of wheat reflects the 87 Sr/86 Sr ratio of the associated environment including soil and groundwater. It is expected that the use the parameters of 87 Sr/86 Sr ratio, the contents of Rb and Sr will allow to trace geographical origin of wheat.