Fluorescein Hydrazide-Appended Metal–Organic Framework as a Chromogenic and Fluorogenic Chemosensor for Mercury Ions |
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| Authors: | Aasif Helal Muhammed Naeem Mohammed Fettouhi Md Hasan Zahir |
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| Institution: | 1.Center of Research Excellence in Nanotechnology (CENT), King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia;2.Department of Chemistry, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia;3.Interdisciplinary Research Center for Renewable Energy and Power Systems, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia; |
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| Abstract: | In this work, we prepared a fluorescein hydrazide-appended Ni(MOF) (Metal–Organic Framework) Ni3(BTC)2(H2O)3]·(DMF)3(H2O)3 composite, FH@Ni(MOF). This composite was well-characterized by PXRD (powder X-ray diffraction), FT-IR (Fourier transform infrared spectroscopy), N2 adsorption isotherm, TGA (thermogravimetric analysis), XPS (X-ray photoelectron spectroscopy), and FESEM (field emission scanning electron microscopy). This composite was then tested with different heavy metals and was found to act as a highly selective and sensitive optical sensor for the Hg2+ ion. It was found that the aqueous emulsion of this composite produces a new peak in absorption at 583 nm, with a chromogenic change to a pink color visible to the naked eye upon binding with Hg2+ ions. In emission, it enhances fluorescence with a fluorogenic change to green fluorescence upon complexation with the Hg2+ ion. The binding constant was found to be 9.4 × 105 M−1, with a detection limit of 0.02 μM or 5 ppb. This sensor was also found to be reversible and could be used for seven consecutive cycles. It was also tested for Hg2+ ion detection in practical water samples from ground water, tap water, and drinking water. |
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| Keywords: | metal– organic framework composite fluorescein hydrazide chromogenic fluorogenic |
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