E mosafayian - Master of nano Technology, Medical Islamic azad University, Tehran, Iran
H. Shirkhanloo - Research Institute of Petroleum Industry, West Entrance Blvd., Olympic Village, P.O. Box: ۱۴۸۵۷-۳۳۱۱۱, Tehran, Iran

A simple in-vitro speciation of inorganic selenium (SeIV and SeVI) and organic selenium (Se-Cys, Se-T, Se-Alb Se-M) in blood and urine of hyperthyroidism and hypothyroidism patients based on isopropyl 2-[(isopropoxycarbothiolyl) disulfanyl] ethane thioate (IICDET) as a complexing agent were studied by ultrasound-assisted dispersive liquid-liquid bio-microextraction (USA-DLLMBE). In first stage, 100 μL (≈0.1 g) of hydrophobic ionic liquid of [C8MIM][PF6] were only added to organic selenium (Se-Cys, Se-M, and Se-ALB) in 10 mL of standard solution and human serum, urine and plasma samples that were thermally extracted into IL phase at human biological pH in 10 min and after dilution with 100 μL of acetone, directly determined by electro thermal atomic absorption spectrometry (ET-AAS). In second stage, after separation IL from sample, inorganic selenium (Se IV) in remained samples was complexed by IICDET and extracted to IL at pH=4 (R-S2Se-R). After reduction Se (VI) to Se (IV) by HCl with temperature 130OC, inorganic Se speciation was obtained based on total Se determination. After optimized conditions, the enrichment factor (EF), Linear range and limit of detection (LOD) for inorganic selenium were obtained 25.2, 0.02- 1.35 μg L-1 and 5 ng L-1 in human biological samples respectively. The results showed us, the concentration of selenium was decreased in thyroid patients as compared to healthy peoples. Based on results, the mean concentration of total selenium in urine and serum of hypothyroidism patients was obtained 11.8 μg g-1 creatinine and 52.6 μg L-1 which was less than 25 μg g-1 creatinine and 150 μg L-1 as TLVs in standard references. The validation of methodology was achieved by certified reference material (CRM) and ICP-MS.

Selenium, Speciation, Inorganic and Organic selenium compound, Isopropyl [(IsopropoxyCarbothiolyl) Disulfanyl] Ethane Thioate, Ultrasound-assisted dispersive liquidliquidbio-microextraction, Human samples.