Sensitive chemosensing of nitro group containing organophosphate pesticides with MOF-5

A luminescent metal-organic framework, MOF-5 [Zn4O (BDC)(3) (BDC = 1,4-benzenedicarboxylate)] has been synthesized by the reaction of zinc nitrate and terephthalic acid in diethylformamide (DEF) medium. The obtained fluorescent porous material has been characterized by X-ray diffraction, transmission electron microscopy, confocal microscopy, UV-vis spectroscopy, photoluminescence spectroscopy and surface area analysis. The synthesized MOF exhibits reasonably good fluorescence characteristics (excitation wavelength = 330 nm, emission wavelength = 493 nm). The potential of above Zn based MOF for the sensing of nitro group containing organophosphate pesticides (OPs), namely parathion, methyl parathion, paraoxon and fenitrothion, is demonstrated. It has been possible to detect the above four OPs separately in the concentration range of 5-600 ppb. The detection limit of the proposed method for all the said OPs is 5 ppb. Interestingly, their mixture also shows the above characteristic data. The proposed method for the sensing of nitro OPs is selective towards other OPs e.g., malathion, dichlorvos and monocrotophos. (C) 2014 Elsevier Inc. All rights reserved.