Direct Atomic Absorption Spectrometric Determination of Selenium in Biological Fluids by a Graphite Filter Furnace Atomizer with Carbon Thread

A rapid and simple method was developed for the determination of selenium in biological fluids by direct electrothermal atomic absorption spectroscopy. The operation parameters of a commercial longitude heating furnace combined with a graphite filter furnace, graphite thread (tube-in-tube atomization system), and a Pd–Mg chemical modifier were proposed, and the corresponding analytical characteristics for the determination of Se at concentrations greater than or equal to 0.0025?mg/kg in blood, urine, saliva, and breast milk samples were established. Recovery values of Se with the proposed method varied within 93 to 107% for these matrices. Relative standard deviations for the analysis of certified material were also compatible; values of 5 and 7% were achieved for blood serum and urine, respectively. The relative standard deviation obtained by the proposed method did not exceed 8%, and the total time for Se determination was 5 to 7?min. The novelty of this technique is that it offers an effective tool for removing the interferences from 10 to 20?g/L organic and 1.0 to 1.5?g/L mineral components in the materials and for significantly reducing the background absorption of light caused by their presence.