Evaluation of Chromium and Manganese levels in sports supplements using graphite furnace atomic absorption spectrometry

Abstract

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.

Modified Proline Metabolism and Prolidase Enzyme in COVID-19

“…Serum prolidase enzyme concentrations were determined with Chinard reagent according to the spectrophotometric assay defined by Myara et al 12 Measurements were made using a Siemens Advia 1800 chemistry analyzer (Siemens Healthcare, Erlangen, Germany). Serum manganese levels were determined in a graphite furnace containing an atomic absorption spectrometer (AAS; Thermo Fisher Scientific ICE 3000 series, Waltham, MA) using the method proposed by Lisboa et al 13 Serum Zn levels were measured using a Zn hollow cathode lamp (HCL) at a wavelength of 213.9 nm in an AAS-flame unit (Thermo Fisher Scientific ICE 3000 series). 14 Serum Cu levels were measured using a Cu HCL at a wavelength of 324.8 nm in an AAS-flame unit (Thermo Fisher Scientific ICE 3000 series).…”