Highly Sensitive Fluorescence Detection of Hg2+ Based on a Water-soluble Conjugated Polymer with Carboxylate Groups

A label-free, highly selective, and highly sensitive fluorescent sensor to detect Hg2+ was developed using a water-soluble conjugated polymer with carboxylate groups (poly(2,5-bis(sodium 4-oxybutyrate)-1,4-phenylethynylene-alt-1,4- phenyleneethynylene, PPE-OBS) in this work. The fluorescence of PPE-OBS would be quenched because of the effect among the unique coordination-induced aggregation and electron transfers of PPE-OBS toward Hg2+. The linear relationship between the fluorescence intensity and concentration of Hg2+ was observed within the range from 6 × 10−8 to 8 × 10−5 mol L−1 (R2 = 0.9985), and the limit of detection was 2.10 × 10−9 mol L−1. The proposed method was applied to detect Hg2+ in environmental water samples, and satisfactory results were obtained.