The difference in composition of inorganic elements between black-seeded soybeans "Tanbaguro" produced in Japan and China

Seed samples of 15 black-seeded soybean "Tanbaguro", 10 collected in Japan and 5 in China including a mutant of "Shin-tanbaguro", were digested with nitric acid using a microwave digestor. The digested residues were dissolved in a 1% HNO3 solution, and inorganic elements (Al, Mn, Ni, Cu, Zn, Sr, Ba, Rb and Cs) were quantitatively analyzed by ICP-MS using In as internal standard. By statistical analysis (cluster analysis and PCA) of the concentrations of 7 elements (Al, Ni, Cu, Sr, Ba, Rb and Cs), a significant difference was detected between Japanese and Chinese samples. The possibility of verifying the producing distinct of "Tanbaguro", Japan or China the difference in composition of inorganic elements was discussed.