Development of flow injection analysis-solid phase extraction based on ion imprinted polymeric nanoparticles as an efficient and selective technique for preconcentration of zinc ions from aqueous solution

Here, a new flow injection analysis-solid phase extraction (FIA-SPE) technique was developed by using zinc ion imprinted polymeric nanoparticles (Zn-IIP NPs) for the separation and preconcentration of Zn2+ ions from aqueous solutions. For the synthesis of a nano-sized Zn-IIP, a stable chelate of Zn2+ ions with 3,5,7,2′,4′-pentahydroxyflavone was formed and then it was copolymerized with methacrylic acid, in the presence of ethyleneglycoldimethacrylate, through a precipitation polymerization technique. From the scanning electron microscopic images, the prepared Zn-IIP NPs were observed to be spherical in shape with an average particle size of 63 nm. Based on the Brunauer–Emmett–Teller adsorption isotherm studies, the surface area, pore volume and average pore diameter of the Zn-IIP NPs were found to be 211.9 m2 g−1, 10 484 cm3 g−1 and 19.8 nm, respectively. After characterization, a FIA-SPE setup was designed based on the prepared Zn-IIP NPs, as a potential selective solid phase extractor toward Zn2+ ions. In the determination step, a standard spectrophotometric method was performed based on the formation of a colored complex between the eluted Zn2+ ions and an ethanolic solution of dithizone (λmax = 538 nm). The optimum experimental conditions for quantitative preconcentration and determination of Zn2+ ions were achieved at pH 6.0 and 5.0 of the initial sample and complex solution, at the loading and leaching flow rates of 0.5 and 5 mL min−1, respectively. The present FIA-SPE procedure offers a reasonable detection limit (3.93 × 10−7 mol L−1) and preconcentration factor (116.7) with acceptable repeatability (1.91%).