Cu-Based Metal-Organic Framework Nanoparticles for Sensing Cr(VI) Ions

A nanoscale MOF-199 was synthesized in a simple and fast way by mixing btc triethylammonium and copper nitrate solution at room temperature and characterized by scanning electron microscopy, transmission electron microscopy, Fouriertransform infrared spectroscopy, and X-ray diffraction. The mimicking enzyme activity and the steady-state kinetics of the nanozyme were investigated. The prepared MOF-199 was a uniformly nanosized octahedron, and it exhibited excellent Cr(VI)-activated oxidoreductase catalytic properties. MOF-199 was employed as a catalyst; in 5 min, 3,3',5,5'-tetramethylbenzidine (TMB) was oxidized by Cr(VI) into a bluish and oxidized TMB, which was recorded by UV-vis spectroscopy, and the mechanism was discussed. It facilitated the sensing of COO, and a linear range of 0.1-30 mu M was obtained with a limit of detection of 20 nM. The selectivity of the present method for Cr(VI) was excellent, and its application to environmental water samples was accomplished.

Automated summary

The research demonstrated that the synthesized nanoscale MOF-199 exhibited excellent Cr(VI)-activated oxidoreductase catalytic properties for spectroscopy recording and COO detection. The study also showed that the method had good selectivity for Cr(VI) and could be applied to environmental water samples.