Abstract
This paper proposes a method for the determination of total selenium in eggs employing hydride generation atomic fluorescent spectrometry (HG AFS). The optimization step of the experimental conditions for quantification of selenium was performed using factorial design and Doehlert matrix involving the factors: pre-reduction time, pre-reducing volume, hydrochloric acid concentration and sodium tetrahydroborate concentration. The procedure of sample preparation was established using a digester block and a reflux system “cold finger” using nitric and hydrochloric acids and oxygen peroxide.
Using the optimized conditions, this method allows the determination of selenium using external calibration technique with limits of detection and quantification of 0.04 and 0.13 ng g-1, for a sample mass of 0.2 g. The precision expressed as relative standard deviation is lower than 4.7%, and the accuracy was confirmed by analysis of a certified reference material of oyster tissue furnished by the National Institute of Standards and Technology, and also by development of addition/ recovery tests. The method was applied for determination of total selenium in egg samples of chicken, quail and paw, being that the total selenium content found varied from 0.35 to 0.88 g g-1. The results achieved by proposed method were compared with those found employing inductively coupled plasma mass spectrometry (ICP-MS). A statistical method demonstrated that there is no significant difference between the results found by two methods.
Keywords: Birds, eggs, HG AFS, multivariate optimization, total selenium.
Graphical Abstract
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