Preparation and Application of Nanostructure Ion-Imprinted Polymer for Selective Solid-Phase Extraction of Pb Ions in Water, Hair, and Food Samples

In this research, nanostructure Pb(II) ion-imprinted polymer (IIP) was prepared by formation of 1,5-diphenylthiocarbazon (dithizone) complex. Polymerization was performed via bulk polymerization, with methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the cross-linking monomer in the presence of ammonium persulfate as the initiator. To characterize the synthesized IIP, FTIR spectroscopy and field emission scanning electron microscopy were used. This polymer was used for selective preconcentration of ultra-trace amounts of Pb ions through the SPE method. The Pb ion concentration was determined by electrothermal atomic absorption spectrometry. In the optimization process, the effects of various factors, such as pH of the sample solution, type and concentration of eluent, equilibrium sorption and desorption times, and sample volume, were investigated. Under optimized conditions, the maximum sorbent capacity was 38.46 mg/g and the enrichment factor was 200. Linearity was within the range 1.0-320.0 ng/L, with good r(2) values. The LOD was 0.55 ng/L, and the intraday and interday RSD values (n = 7, 20 ng/L Pb ions) were 2.8 and 3.5%, respectively. This selective and sensitive proposed method was applied successfully to the determination of Pb in water, hair, and food samples, with high recoveries.