▎ 摘　　要

A sensor made of Fe3O4TiO2@NG@Au@ETBD was developed to specifically detect Pb2+ in a significantly toxic aqueous environment. Nitrogen-doped graphene (NG) was utilized as the substrate material of the sensor by a self-assembly method. The synergistic effect of the Fe3O4@TiO2 as well as the expanded activated surface and good electrical conductivity of the gold nanoparticies enhanced the detection of Pb2+. 2, 2'-((lE)-((4-((2-mercaptoethyl) thio) -1, 2-phenylene) bis (azanylylidene)) bis (methanylylidene)) diphenol (ETBD) was employed as the capture probe for the label-free detection. The electrical characteristics of the Fe3O4@TiO2@NG@Au@ETBD sensor were monitored to measure and investigate the performance of the sensor. Compared with conventional detection technologies and electrodes, this sensor enabled a wide linear range from 4 x 10(-13) mol/L to 2 x 10(-8) mol/L. Lower limits of detection and quantification for Pb2+, 7.5 x 10(-13) and 2.5 x 10-12 mol/L, respectively, were achieved. Furthermore, the Fe3O4@TiO2@NG@Au@ETBD sensor could distinguish Pb2+ from other metal ions despite the interfering metal ions with concentrations 10(3)-fold higher than that of Pb2+. The proposed sensor could potentially be used in heavy-metal detection. (C) 2016 Elsevier B.V. All rights reserved.