Analytical Sciences

Strontium and Lead Isotope Analyses for Determining the Geographic Origins of Grains

Kaoru ARIYAMA,* Miyuki SHINOZAKI,* Akira KAWASAKI,** and Yoshiki ISHIDA***

*Tokyo Research Laboratory, Japan Grain Inspection Association, 1-2-1 Shiohama, Koto, Tokyo 135-0043, Japan
**National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Ibaraki 300-2611, Japan
***Cereal Science Research Center of Tsukuba, Nisshin Flour Milling Inc., 13 Ohkubo, Tsukuba, Ibaraki 300-2611, Japan

A rapid determination method of ⁸⁷Sr/⁸⁶Sr and Pb isotope (²⁰⁴Pb, ²⁰⁶Pb, ²⁰⁷Pb, and ²⁰⁸Pb) ratios was applied to determining the geographic origin of grain crops. This new method is more economical in terms of both time and cost compared to conventional methods. We used samples of barley (n = 321), rice (n = 111), and wheat (n = 93) grown in various countries. ⁸⁷Sr/⁸⁶Sr versus Sr concentration plots for the barley and wheat showed differences between products from Australia and those from other countries. Graphs of the Pb isotope ratios, comprising 15 two-dimensional plots, gave rise to a particular distribution for each country of production. The presented method showed promise for determining the production countries of grains by using the isotope ratios of Sr and Pb.

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