Chemical characterization of minerals from a commercial vitamin supplement using X-ray fluorescence and a portable equipment

Vitamins and mineral supplements are largely consumed by adult population; nevertheless, research has indicated that an inadequate ingestion of supplements may be more harmful than beneficial to the human body. This way, it is important to know the elemental chemical composition of such products. The technique employed in this work was energy dispersive X-ray fluorescence (EDXRF), using a portable equipment. The validation of the method was carried out by analysing two certified reference materials: SRM-1832 e 1833. Three samples of coated compressed tablets were selected, ground and then reconstructed in the form of pastile. The concentrations found, and their respective experimental errors, in μg g-1, were: Cl (22.4 ± 4.40), K (26.0 ± 1.15), Ca (148.7 ± 3.25), Mn (2.9 ± 0.54), Fe (6.3 ± 0.36), Cu(4.0 ± 0.14), Zn (70.9 ± 1.88), Se (0.1 ± 0.01), Br (0.2 ± 0.02), Sr (0.2 ± 0.01) and Mo (0.1 ± 0.01). It was possible to determine the detection limit for the elements Ca (0.29), Fe (0.09), Cu(0.05) e Zn(0.22), in μg g-1. From the eleven elements found in the analysed supplement sample, three (Cl, Br e Sr) were not mentioned in the product printed instructions (bull) and other three mentioned elements (V, Cr, Ni) have not been detected.