Copper-based metal-organic framework nanoparticles for sensitive fluorescence detection of ferric ions

A luminescent amino-functionalized metal-organic framework (Cu-MOFs) was synthesized from 2-aminoterephthalic acid and Cu(ii) ions by a solvothermal method. Cu-MOFs displayed blue fluorescence with a peak at 430 nm under 330 nm excitation. Its structure was characterized by FTIR, TEM, XRD, and XPS. The fluorescence of the Cu-MOFs was quenched by Fe3+ in aqueous solutions. The limit of detection was 0.5 mu M, and the linear working range extended from 2 mu M to 35 mu M. Additionally, a good logarithmic relationship between relative fluorescence intensity (F/F-0) and Fe3+ concentrations ranging from 2 to 180 mu M was obtained with a detection limit of 1.56 mu M (R-2 = 0.9975). No clear interference was observed when challenged with a wide variety of cations and anions. The recoveries from spiked real water samples were in the range of 91.7-107.7%, and the detection results were consistent with inductively coupled plasma mass spectrometry (ICP-MS) results. Therefore, the fluorescent sensor has great potential in environmental monitoring.