Objective In this paper, we studied three different types of ordinary sports supplements containing whey protein: whey protein-based ones, hypercaloric ones, and protein bars. Methods A sample preparation procedure was studied employing microwave-assisted wet digestion in order to determine the Chromium and Manganese levels by graphite furnace atomic absorption spectrometry. Results The developed methods have presented good accuracy (recoveries in the range of 90% to 109%) and precision (Relative standard deviation <8%). Although an adequate detectability was obtained (50ng g-1 for Manganese and 65ng g-1 for Chromium), the sample preparation method was also adequate to inductively coupled plasma mass spectrometry analysis. The method was applied to 26 commercial samples, in which the Chromium concentrations were in the range between 0.22 and 1.0μg g-1 and the Manganese concentrations varied from 2.0 to 37μg g-1. Conclusion The results obtained by atomic absorption for both analytes were in agreement with those obtained by mass spectrometry. In addition, some samples presented concentrations of Chromium above the recommended daily intake and, as a result, we used the X-ray powder diffraction technique as an analytical tool to evaluate the oxidation state of Chromium in such samples.

In order to build a metal-organic framework with mixed ligands (acid-acid), a 3D coordination network based on manganese metal center was obtained [Mn3(BTC)2(DMSO)4]n; where BTC = Benzene-1,3,5-tricarboxylic acid and DMSO = Dimethylsulfoxide. The crystal structure was determined by single crystal X-ray diffraction, showing the assembly of a tridimensional 3,6-connected non-entangled polymeric network, with RTL topology. The secondary building unit (SBU) acts as a node of the 3-periodic expansion and involves carboxylate- and oxo-bridged metals. The DMSO employed in the synthesis is chemically involved in the coordination as a µ2-O bridge between distinct manganese metal centers. The structural characterization of the material was supported by spectroscopic (infrared absorption and Raman scattering), thermal (TG, DTG, and DTA) and elemental analysis.