Study Of Fluorescent Probe For Heavy Metal Ions Based On Rhodamine

With the rapid development of industry, the heavy metal pollution has become more serious. As the heavy metal ions play a significant role in the fields of life science, medicine and environmental science, putting forth an approach that could monitor the heavy metal ions in real time is important as well as meaningful. The pollution prevention has focused on the issue of mercury pollution because the mercury ion could cause neurotoxicity and nephrotoxicity-based multi-system damage to human’s body when it enters human’s body in various ways. Copper can participate various reactions in human body. However, the excess intake of copper would cause a series of neurological diseases. Also, once the copper bearing water is dumped into the clear water, it will be toxic to aquatic organisms.We chose the fluorescence analysis method to detect the heavy metal ions and selected the rhodamine group as the fluorophore. Based on the Spirolactam ring-opening system of rhodamine group and the characteristics of1,8-naphthyridine, we connected these two together and finally two fluorescence probe molecule Rh6G-Np and RhB-Np are compounded. The Rh6G-Np is a fluorescence enhanced probe for Hg2+, based on Rhodamine6G and RhB-Np is a fluorescence quenching probe for Cu2+, based on Rhodamine B.Rh6G-Np can identify mercury ion selectively, which won’t be interfered by other metal ions. The fluorescence signal of the solution added with the mercury ion enhances up to134times than before, meanwhile, the color of the solution changes from the colorless to the pink. The composition ratio is1:1. This probe possesses well reversibility with Hg2+. Not only the probe but also the complex with Hg2+works steady in the neutral pH range. The detection limit can achieve0.967nM for Hg2+and it can detect the mercury ions immediately and directly in both Changjiang River and seawater, which can show its practical applications to environmental monitoring and assessment.The fluorescence probe RhB-Np can selectively identify Cu2+, but in the presence of Cr3+, it will have certain interference effect. After adding the Cu2+, the fluorescence signal of the probe quenches obviously. Meanwhile the color of the solution changes from the pink to the rose. The composition ratio is1:1. Its detection limit is at4.107μM and it has a good reversibility when the copper ion was being identified.