Validación de la metodología analítica para cuantificación de Selenio en alimentos de la canasta básica del costarricense

objective: the purpose of this research is to validate the analytical methodology for the determination of selenium in foods of costa rican basic consumption by atomic absorption spectroscopy with hydride generation. materials and methods: the foods were processed according to the pattern of consumption in costa rica. once cooked, samples were taken for moisture determination and for microwave digestion. the quantification was performed on digested samples by atomic absorption spectroscopy with hydride generation using sodium borohydride 0,6 % as a reducing agent in sodium hydroxide 0,5 % and hydrochloric acid 10 mol / l. the samples and standard solutions for calibration curve were acidified with concentrated hydrochloric acid to ph 1, heated to (70-90) ° c for 15 minutes to ensure the +4 oxidation state. validation of the methodology was carried out with selenium standard solutions traceable to nist ？ and certified reference materials traceable. discussion: the quantification was realized in the concentration range between (1.3 to 50) μg / l, with a correlation coefficient of 0.9984, the detection and quantification limits were (1.3 ± 0.2) mg / l and (2.2 ± 0.2) mg / l. the precision was evaluated in terms of repeatability and reproducibility, the results were 0.7 μg / l and 0.9 μg / l calculated as standard deviation, respectively. the veracity was determined using a nist standard ？ certificate, srm 1846 infant formula the bias was of -2.5 %. the foods containing selenium detectable and measurable were: white rice, rice earlier maturity, rolled oats, sweet chile mature peas, beef liver, egg yolk, lentils, tripe, bread, pasta, cream cheese, mozzarella cheese, tilapia fillet, peeled carrot