Use of a new magnetic ion-imprinted nanocomposite adsorbent for selective and rapid preconcentration and determination of trace nickel by flame atomic absorption spectrometry

A novel method for selective and rapid preconcentration and determination of trace nickel (Ni(II)) in aqueous solution was developed by using a magnetic Ni(II)-imprinted chitosan nanocomposite as a new adsorbent for solid-phase extraction (SPE) coupled with flame atomic absorption spectrometry determination. The prepared adsorbent was characterized using Fourier transform-infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and vibrating sample magnetometry (VSM). The parameters that affect the extraction efficiency of Ni(II) were investigated. The optimum conditions, including sample pH, eluent type and volume, and also adsorption and desorption time were obtained. The results indicated that the adsorbent had excellent adsorption selectivity for Ni(II). The analytical performance of the proposed method was evaluated. The enrichment factor for Ni(II) was 92 by using 50 mg of the adsorbent and 200 mL solution. The limit of detection (LOD) and limit of quantification (LOQ) were 0.06 and 0.2 mu g L-1, respectively. The intra-day and inter-day relative standard deviations (RSDs, n = 6) were 1.5% and 1.8%, respectively. The developed method was successfully applied to the analysis of trace Ni(II) in environmental water, and the recovery of the spiked samples was in the range of 96-112%.