▎ 摘　　要

The separation and pre-concentration of pb(2+) ions from mollusk and fish samples were performed by nanocomposite of magnetic graphene oxide-polyimide, as an efficient solid-phase extraction sorbent. The nanocomposite was characterized by field emission scanning electron microscopy, Fourier transform infrared spectroscopy and energy-dispersive X-ray spectroscopy. The parameters affecting the extraction processes including: amount of adsorbent, adsorption and desorption times, type and volume of the eluent solvent and interfering ions of the sample were investigated and optimized. The calibration curve was linear in the concentration ranges of 0.8-400 mu gL (1) (R-2 = 0.998). The limit of detection and quantification were obtained as 0.25 mu g L (1) and 0.80 mu g L (1), respectively. The relative standard deviation was 7.3% and the pre-concentration factor was 141. A gastropod, Trochus erithreus, and a muscle tissue of fish, Otolithes ruber, were analyzed as real samples and good relative spiked recoveries (95-106%) were obtained. (C) 2017 Elsevier Ltd. All rights reserved.