Trace determination of quinoline in various water samples based on Keplerate polyoxometalate nanoadsorbent

Due to the carcinogenic potential of quinolines for humans and toxic properties for the aquatic environment and their widespread use for the manufacture of dyes, considerable research has been devoted to explore the determination methods of quinolines [1]. The unique properties of polyoxometalates (POMs) including structural order, high contact of nanostructured surface, mechanical and chemical stability, high adsorption and rapid separation make them appropriate adsorbents for determination methods. In this research, a Keplerate polyoxometalate-based nanoadsorbent [2] is employed as an adsorbent in the dispersive micro solid phase extraction (Dμ- SPE) for preconcenration and determination of quinoline [3]. The chemical structure, morphology and physical properties of Keplerate were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), scanning and transmission electron microscope (SEM,TEM), thermogravimetric analysis (TGA), N2 adsorption-desorption isotherms and surfacecharge analysis. Different parameters affecting the extraction recovery, including pH, temperature, adsorbent dose, time of adsorption and desorption, were investigated and optimized using a central composite design (CCD) [4]. Under the optimal conditions, the linear dynamic rang (LDR) and limit of detection (LOD) for determination of quinoline were 45-650 ng mL-1 and 13.65 ng mL-1, respectively. Finally, the proposed method was successfully applied for the selective determination of trace amountsof quinoline in various water samples.

Keywords:

Keplerate polyoxometalate , Quinoline , Central composite design , Water samples