Highly sensitive fluorescence detection of Hg ²⁺ based on a water-soluble conjugated polymer with carboxylate groups

A label-free, highly selective, and highly sensitive fluorescent sensor to detect Hg ²⁺ 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 Hg ²⁺ . The linear relationship between the fluorescence intensity and concentration of Hg ²⁺ 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 Hg ²⁺ in environmental water samples, and satisfactory results were obtained.