Desenvolvimento de métodos para determinação de analitos inorgânicos em bebidas empregando procedimentos mínimos de preparo de amostras

Abstract

This work seeks to develop methods of inorganic analytes determination in foods, employing techniques that use a minimum sample preparation and that are environmentally friendly. For this, a method was developed using two-phase aqueous system (SAB), studying the following variables: concentration of extractor agent iodide (280 mmol kg-1), polymer type (PEO1500), type of electrolyte (Na2SO4) forming the percentage system in (%) of Cd (II) (99.8% ± 0.4), mooring line length (32.28% (m / m)) and ratio between upper and lowerphase masses (1,0) from bovine milk. The validated method was applied in the Cd(II) in milk samples determination. Another method developed quantified the inorganic constituents of red wine using XRF fluorescence by total reflection (TXRF) after the dilution of the wine samples and adding Ga solution. The evaluated elements were (mg L-1) P: (27.5-202); S (46-177); Cl (3-182); K (575-1229); Ca (39-119); Ti (0.1-0.3); Mn (0.1-0.3); V (<LD-0.07); Fe (1-3.8); Ni (<LD-0.3); Cu (0.03-0.9); Zn (0.18-1.57); As (0.004-0.03); Br (0.14-13.4); Rb (0.49-4.03); Sr (0.52-2.19); Ba (<LD-0.48) and Pb (<LD-0.01). Another direct analysis method for the quantification of 15 analytes in beer and detection by TXRF was also developed. This procedure of direct analysis was compared to acid digestion to evaluate the matrix effect. Accuracy and precision were assessed using certified reference material. It was analyzed thirty beer samples collected in several regions in Brazil. The evaluated elements were (mg L-1): P:(37.40-140.85); S (10.32-50.73); Cl (82.74-281.7); K (183.8-418.5); Ca (9.82-96.0); Mn (0.06 to 1.42); Fe (0.07-1.57); Ni (<LD-1.13); Cu (<LD-0.32); Zn (0.02-1.98); As (<LD-0.10); Br (0.01-2.04); Rb (<LD-0.52); Sr (<LD-0.41) and Pb (<LD-0.18). The methods developed are simple, fast, environmentally friendly and they can be applied to routine analysis.