Optimization of Selenium Determination Based on the HG-ET-AAS Method for its Application to Different Food Matrices
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Optimization of Selenium Determination Based on the HG-ET-AAS Method for its Application to Different Food Matrices J. R. Marval-León & F. Cámara-Martos & F. Pérez-Rodríguez & M. A. Amaro-López & R. Moreno-Rojas
Received: 6 September 2011 / Accepted: 22 November 2011 / Published online: 16 December 2011 # Springer Science+Business Media, LLC 2011
Abstract Selenium is an important micronutrient in humans and animals, but also is considered toxic at relatively high levels, not far from physiological levels. The objective of this work was to optimize the determination of selenium by FIASfurnace technique for its application in different food matrices. For that, the most influencing factors were previously selected: NaBH4 (in percent weight per volume), HCl (in mole per liter), NaOH (in percent weight per volume), and carrier and reductant flow (in milliliters per minute). Based on these factors, a central composite rotatable design was applied with the calibration curves as optimization criterion. Results indicated that NaBH4 presented the most significant effect, followed by the carrier and reductant flow which showed a negative effect (i.e., lower values resulted high sensitivity). Furthermore, all studied certified reference materials representing different food matrices resulted in very high recovery percentage (i.e., >95%), demonstrating the reliability of the analytical method. Keywords HG-ET-AAS . FIAS-furnace technique . Selenium . Foods . Rotatable central composite design . RCCD
Introduction Selenium is an essential micronutrient which is required at small levels by humans and animals. This micronutrient plays an important role in several physiological functions J. R. Marval-León : F. Cámara-Martos (*) : F. Pérez-Rodríguez : M. A. Amaro-López : R. Moreno-Rojas Departamento de Bromatología y Tecnología de Alimentos, University of Cordoba, Campus de Rabanales, Edificio Darwin C-1, 14040 Córdoba, Spain e-mail: [email protected]
such as forming part of the glutathione peroxidase (Burk et al. 1999) and the iodothyronine-5 deiodinases (Merian et al. 2004). However, selenium may also be toxic for many organisms when presented at high concentrations (Sager 1994) being one of the chemical elements in which there is less difference between essential and toxic levels. According to epidemiological studies, the upper safe limit for selenium might be in the range 750–800 μg/day (Reid et al. 2004). However, values exceeding this threshold could cause adverse effect on health. Hence, it is necessary to develop sensible analytical methods to accurately determine its content in foods. Currently, there are very sophisticated analytical methods such as mass detection which enables to identify different selenium species at low levels. However, many of these techniques are not available to most laboratories because of the high price and maintenance costs derived from the analytical equipment. The hyphenation of common techniques such as chromatography and atomic absorption or fluorescence spectrometry are more cost-effective alte
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