title: Fabrication of an "ion-imprinting" dual-emission quantum dot nanohybrid for selective fluorescence turn-on and ratiometric detection of cadmium ions.
abstract: In this work, we have fabricated a new dual-emission quantum dot (QD) nanohybrid for fluorescence ratiometric determination of cadmium ions (Cd2+) in water samples, where the "turn-on" model and "ion-imprinting" technique were incorporated simultaneously. The nanohybrid probe was composed of green-emitting CdSe QDs covalently linked onto the surface of silica nanoparticles embedded with red-emitting CdTe QDs. The chemical etching of ethylene diamine tetraacetic acid (EDTA) at the surface produced specific Cd2+recognition sites and quenched the green fluorescence of outer CdSe QDs. Upon exposure to different amounts of Cd2+, the green fluorescence was gradually restored, whereas the inner red fluorescence remained constant. As a consequence, an obviously distinguishable fluorescence color variation (from red to green) of the probe solution was observed. Under the optimized conditions, the developed ratiometric sensor displayed a linear response range from 0.1 to 9 μM with a detection limit of 25 nM (S/N = 3) for Cd2+, which could offer an alternative sensing approach for the highly sensitive and selective detection of heavy metal ions.
authors.affiliation: College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, 310014, P.R. China. Jingw1986@zjut.edu.cn.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Chenxing
authors.initials: C
authors.lastname: Jiang
authors.forename: Xiaoqi
authors.initials: X
authors.lastname: Wang
authors.forename: Ligeng
authors.initials: L
authors.lastname: Wang
authors.forename: Aimin
authors.initials: A
authors.lastname: Chen
authors.forename: Jun
authors.initials: J
authors.lastname: Hu
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Luo