Facile and Green Synthesis of Zeolite Imidazolate Framework for Preconcentration and Determination of Folic Acid in Various Food Samples

In this work, a nano porous zeolitic imidazolate frameworks-8 (ZIF-8) was successfully fabricated as a selective and green adsorbent for dispersive micro–solid phase extraction (Dμ-SPE) to extraction and preconcentration of folic acid [1,2]. Zeolitic imidazolate frameworks (ZIFs) consist of metal nodes connected to imidazolate linkers, having both the properties of metal-organic frameworks (MOFs) and inorganic zeolites, such as controllable pore sizes, high porosity and surface areas, as well as exceptional thermal and chemical stability, thereby making them a class of attractive materials for diverse analytical applications [3]. The properties of the synthesized ZIF-8 were characterized by Fourier-transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD). The main effective parameters on the Dμ-SPE, including solution pH, dose of adsorbent, adsorption time, and desorption time were investigated, and optimized by using a central composite design (CCD) combined with response surface methodology (RSM) [4]. The linear dynamic rang (LDR) and detection limit (LOD) for determination of FA were 8.0-300.0 ng mL-1 and 2.2 ng mL-1 respectively and the relative standard deviation (RSD %) was 2.91 (n=3). Finally the proposed method was successfully applied to monitoring and quantification of folic acid in various food samples.