Development of an efficient sample preparation method for the speciation of Se(IV)/Se(VI) and total inorganic selenium in blood of children with acute leukemia

In this study, a new solidified deep eutectic solvent microextraction (SDES-ME) method was applied for the speciation of Se(IV), Se(VI) and total inorganic selenium in the blood of children with leukemia from Kermanshah, Iran, prior to analysis by iridium-modified tube graphite furnace atomic absorption spectrometry (GFAAS). Choline chloride-decanoic acid in the molar ratio of 1 : 2 was used as a green hydrophobic deep eutectic-based floating organic droplet microextraction solvent for the extraction of the Se(IV)-DDTP complex from real blood samples. In the SDES-ME, 60 mu l of DES as the extraction solvent containing 15.0 mu l chelating agent was rapidly injected into the sample solution. Under the optimum conditions, the enrichment factor and enhancement factor were 112 and 99, respectively. The calibration graph was linear in the range of 0.05-5.0 mu g l(-1) with the detection limit of 0.015 mu g l(-1). The repeatability (intra-day) and reproducibility (inter-day) of the method based on seven replicate measurements of 2.0 mu g l(-1) of selenium were 2.2% and 3.5%, respectively. The results showed that there was no significant difference between the levels of selenium in girls and boys, and with increasing age, the selenium blood levels increased in both girls and boys. Moreover, the results showed no significant difference in the selenium levels in cancerous and non-cancerous children. However, in a number of samples, the selenium levels in cancerous children were lower than those in the non-cancerous children probably due to the administration of drugs used in chemotherapy.