Ultrasonic extraction combined with fast furnace analysis as an improved methodology for total selenium determination in seafood by electrothermal-atomic absorption spectrometry

Abstract

Based on the analytical minimalism concept outlined by Halls [J. Anal. Atomic Spectromet. 10 (1995) 169], a fast methodology for determination of Se in seafood by electrothermal-atomic absorption spectrometry (ETAAS) is proposed. The following features are considered in order to meet with such a concept: (i) rapid sample preparation based on accelerated extraction of Se by means of ultrasound; (ii) shortening of the thermal program by omission of the pyrolysis stage; (iii) use of simple aqueous standards for calibration. Addition of a Pd matrix modifier was seen to be needed for quantitative recovery of Se. The method was validated against two certified reference materials and subsequently applied to determination of Se in six seafood samples. Contents ranged from 1 to 3 μg g −1. The limit of detection was 0.16 μg g −1 and the precision, expressed as relative standard deviation, was in the range 3–12%. Re-adsorption of Se was seen to be a source of error which could be overcome by working with low-acidity media.