Highly sensitive and selective fluorescence detection of Hg(ii) ions based on R-phycoerythrin from Porphyra yezoensis

R-Phycoerythrin (R-PE) is a kind of natural fluorescent protein from marine Porphyra yezoensis. A highly sensitive and selective fluorimetric method has been developed to detect Hg²⁺ ions utilizing R-PE as a fluorescent probe. R-PE could respond selectively to Hg²⁺ ions among a series of metal ions. The reaction mechanism was investigated through UV-vis, fluorescence microscope imaging and fluorescence measurements. It was demonstrated that the interaction between the R-PE fluorescent probe and Hg²⁺ ions would cause fluorescence quenching. Besides, there was a linear relationship between R-PE fluorescence intensities and Hg²⁺ concentrations. A novel method was thus explored to detect Hg²⁺ ions with high sensitivity, selectivity, and a broad linear range of 0.0010-25.0 μM, which could allow for Hg²⁺ ions down to 0.0130 μM with a relative standard deviation of about 1.60%. Additionally, the method was successfully applied to detect Hg²⁺ ions in diverse water samples, showing the appropriate rates of recovery between 92.0% and 108.0%. This highly sensitive and selective natural green fluorescent probe of R-PE should have huge potential applications for detecting Hg²⁺ ions in diverse environments.