Rouhollah Khani - Department of Chemistry, College of Sciences, University of Birjand, Birjand, Iran
Mozhdeh Chahkandi - Department of Chemistry, College of Sciences, University of Birjand, Birjand, Iran
Abdolreza Rezaeifard - Department of Chemistry, College of Sciences, University of Birjand, Birjand, Iran

Due to the chemical stability of polycyclic aromatic hydrocarbons (PAHs), carcinogenic, mutagenic and toxicproperties as well as long-lasting effects on human health and environment, considerable research is devoted to explorethe determination methods of PAHs [1]. Polyoxometalates (POMs) are specific class of molecular metal oxidecompounds of inimitable electronic and structural diversity that influence many fields of science and technology, suchas catalysis, materials science, biology and medicine. The unique properties of POMs including structural order, highcontact of nanostructured surface, mechanical and chemical stability, high adsorption and rapid separation make itappropriate adsorbents for determination methods [2]. A Keplerate polyoxometalates (POMs)-based nanoadsorbentwas synthesized via an efficient chemical method and employed as an adsorbent in the dispersive micro solid phaseextraction (Dμ-SPE) for determination of phenanthrene as one of PAHs [3]. The chemical structure, morphology andthermo stability of the as-synthesized POMs were characterized by Fourier transform infrared spectroscopy (FT-IR),Raman spectroscopy, X-ray diffraction (XRD), transmission electron microscope (TEM), thermogravimetric analysis(TGA) and N2 adsorption-desorption isotherms. A central composite design (CCD) was used for evaluation andoptimization of various parameters affecting the extraction efficiency such as pH, temperature, adsorbent dose, time ofadsorption and desorption [4]. Under the optimal conditions, the linear dynamic rang (LDR) and limit of detection(LOD) for determination of phenanthrene were 15-230 ng mL-1and 4.3 ng mL-1, respectively. Finally, the proposedmethod was successfully applied for the selective determination of trace amounts of phenanthrene in various realsamples.

Keplerate polyoxometalate; Phenanthrene; Dispersive micro- solid phase extraction; Central composite design