R-Phycoerythrin Proteins@ZIF-8 Composite Thin Film for Mercury Ions Detection
Mercury, as one of the most prevalent toxic metals released by various natural and anthropogenic processes, causes severe pollution of soil and groundwater. In this work, R-Phycoerythrin (R-PE) proteins encapsulated in ZIF-8 composite thin films were prepared via a solid-confinement conversion process and applied as fluorescent sensor for mercury ions detection. The R-PE proteins encapsulated in ZIF-8 exhibit dual colors emission including green (518 nm) and red (602, 650 nm) fluorescence, while the original orange emission (578 nm) of pure R-PE is significantly suppressed. R-PE@ZIF-8 presents excellent selectivity and sensitivity for mercury detection in a large pH range without buffer solution. Under the optimal conditions, there is a good linear relationship for mercury ions in the range of 0.001-50 µM with the detection limit (LOD) of 6.7 nM much lower than the guideline value given by the World Health Organization. Furthermore, multi-peak detection of R-PE@ZIF-8 improves the detecting accuracy of Hg2+ concentration.