Direct electrothermal atomisation atomic absorption spectrometric determination of selenium in whole blood and serum with continuum-source background correction

Abstract

In the determination of selenium, the well documented spectral interferences originating from phosphates and iron present in the biological fluids are eliminated by the addition of platinum. Pre-atomisation losses of selenium are avoided in the presence of nickel (15 µg) and platinum (60–120 µg). Using a pyrolytically coated tube together with off the wall atomisation, the sensitivity in terms of characteristic mass is 60 pg (0.0044 A s), while the detection limit (twice the base-line noise) is 3 ng ml^–1. Within-run precision is better than 8% while between-run relative standard deviation is less than 10%. Validation of the developed method has been made by using a certified reference material and by comparing the results with hydride generation and neutron activation analysis. The proposed method is rapid, accurate and precise and can be used for analysing up to 50 serum samples per day.