Highly sensitive fluorescent sensor for mercury (II) ion based on layer-by-layer self-assembled films fabricated with water-soluble fluorescent conjugated polymer

In this paper, a simple and sensitive Hg (II) sensor based on the water-soluble fluorescent conjugated polymer multilayer films was developed. The multilayer films were fabricated successfully utilizing layerby-layer self-assembly technology via the electrostatic interaction between polycation electrolyte PDDA and sulfonic group anion surrounded conjugated polymer PPES03. In the presence of Hg (II) ion, the photoluminescence (PL) of PDDAIPPES03 multilayer films quenched effectively without obvious maximum PL emission wavelength shift. The PL intensity ratio loll (lo and I are the fluorescence intensity of PDDAIPPES03 multilayer films in the absence and presence of Hg(II) ion, respectively) was proportional to the concentration of Hg (II) in the concentration ranges of 2.0 x 10(-7) to 3.0 x 10(-5) mol L-1. The detection limit (LOD) for Hg (II) was 1.0 x 10(-7) mol L-1. The proposed film sensor was successfully applied for the determination of Hg (II) in several water samples with satisfactory reproducibility and accuracy. This work may provide a common platform for the further development of various solid-state portable devices. (C) 2013 Elsevier B.V. All rights reserved.