Effective procedures for the determination of As, Cd, Cu, Fe, Hg, Mg, Mn, Ni, Pb, Se, Th, Zn, U and rare earth elements in plants and foodstuffs

There are several international regulations regarding trace elements. The use of ICP-MS for their determination is usually a difficult task, especially when Hg is one of the target elements. This work aimed to provide a fast, simple and low-cost method for routine digestion of different foodstuffs aiming at the determination of As, Cd, Cu, Fe, Hg, Mg, Mn, Ni, Pb, Se, Th, Zn, and U as well as rare earth elements. Four conditions were evaluated for sample heating: a water-bath (WB), a digester block (DB) and a microwave oven (MW) under medium (MWMP) and high-pressure (MWHP). Low-cost homemade PTFE-vessels were used for the WB and DB. The MWHP presented the best recoveries for all elements. The use of the WB and DB allowed the determination of all elements in animal tissues and grains, except Hg. The use of l-CYS 0.2% m/v and a MWHP was crucial for Hg determination. Therefore, this study shows high-frequency methods crucial for industry and labs that focus on food monitoring, especially due to the new regulations in progress worldwide.