A Zn based anionic metal-organic framework for trace Hg2+ ion detection

As one of the most toxic heavy metal ions, Hg2+ exists widely in the living surroundings of human beings and excessive Hg2+ possesses a great threat to human health. The maximum allowable concentration of Hg2+ in drinking water is only 10 nM (2 ppb) by U.S. EPA standard. Ionic metal-organic framework (iMOF) is considered in view of high sensitive, anti-interferential material for Hg2+ detection still remain a challenge. Herein we designed and synthesized a novel Zn based anionic MOF Zn-TPTC, which was characterized by single crystal diffraction and other method. Its performance on Hg2+ (10-6-10-4 M) detection were studied and the detection limit (LOD) is calculated as low as 3.67 nM. Interference experiments showed that Zn-TPTC could exclude the interference of other ions, which could be attributed to the effective pore size, anionic framework and multiple N sites in ligand, providing us new ideas for the selection and design of MOF for detection application.