Geração fotoquímica de vapor acoplada a espectrometria de absorção atômica para a determinação de selênio em feijão verde

Abstract

One of the essential micronutrients for human health is selenium. It is responsible for acting as the body's defense mechanism, but both a deficiency and an excess of this element in the body can cause damage to health. The biggest source is food, such as nuts, rice and beans. In this work, the determination of selenium in green beans was carried out using the hydride generation coupled to atomic absorption spectrometry and the photochemical vapor generation coupled to atomic absorption spectrometry, with the aim of comparing the two methods, in order to evaluate the efficiency of both. The development of the photochemical vapor generation (PVG) method began by optimizing the method's experimental conditions, such as: carrier gas flow, sample exposure time to UV radiation, type and concentration of the organic precursor used for photoreduction of selenium and the formation of radicals. The formation of volatile species achieved greater efficiency using acetic acid 6,0% as an organic precursor, a carrier gas flow rate of 10 mL min-1, and an exposure time to UV radiation of 20.31 s. The calibration curve used was by addition of standard due to possible matrix effects, all the curves had a correlation coefficient above 0.99. The analyzed samples presented Selenium concentration range from 0.9 to 2.2 mg kg-1 Se in dry matter of green beans, showing that the concentration is within the expected when compared to other types of beans found in the literature.