Elemental content of Vietnamese rice. Part 1. Sampling, analysis and comparison with previous studies

Various rice samples were collected in Vietnam from the Red River region, and some other parts of the country as well as from Yanco, NSW, Australia. The rice samples were analysed for 14 elements (P, K, Mg, Ca, Mn, Zn, Fe, Cu, Al, Na, Ni, As, Mo, and Cd) by ICP-AES, ICP-MS and FAAS. The analytical procedures were carefully controlled and validated using the rice flour certified material (NIES No 10). In general, the results showed that Vietnamese rice has elemental concentration ranges similar to those of the Australian and other overseas rice. However, analyses for some elements are characteristic of some Vietnamese and Australian rice samples. Thus, Vietnamese rice shows somewhat higher levels of P, K and Mg than rice samples from other countries; Mn could be a marker for the Australian rice grown in the Yanco region, and the analysed Australian samples were also very low in Cd (< 0.003 mg kg-1). An unusual distribution of Ni, present in higher concentrations in the white rice samples than in the brown ones, was observed for some Vietnamese rice samples.