•Post-synthetic covalent modification of metal-organic frameworks was used to prepare fluorescent UMCM-4-NH2-ECIT.•UMCM-4-NH2-ECIT increased the specificity of sensing Fe3+ through the introduction of ECIT groups into organic ligands.•UMCM-4-NH2-ECIT displayed fast response, high sensitivity, wide detection range, and excellent selectivity toward Fe3+.A post-synthetic modification method was developed to prepare fluorescent metal organic frameworks by the covalent interaction of ethoxycarbonyl isothiocyanate with amine functionalized UMCM-4. X-ray diffraction spectrometry, X-ray photoelectron spectrometry, elemental analysis, Fourier-transformed infrared spectroscopy, nuclear magnetic resonance spectrometry, thermogravimetric analysis/derivative thermogravimetry analysis, and nitrogen sorption isotherms were employed to characterize the modified metal organic frameworks. With high emission efficiency and excellent fluorescence stability, the sensing properties of Fe3+ were studied. Possible mechanisms of energy and electron transfers between the target and the fluorescent probe were demonstrated. Effects of response time, Fe3+ concentration, and other metal ions on the fluorescence intensity were also studied.Download high-res image (298KB)Download full-size image

A novel hybrid material incorporating porous aromatic frameworks and an ionic liquid, 1-(triethoxy silyl)propyl-3-aminopropyl imidazole hexafluorophosphate, was prepared as solid-phase microextraction coating and employed for the extraction of organochlorine pesticides. Combining the advantages of porous aromatic frameworks and an ionic liquid, the fiber exhibited a high adsorption capacity for organochlorine pesticides. Under optimized experimental conditions, enhancement factors of 247–1696 were obtained with good linearity in the range of 1–500 μg L−1. The detection limits and quantification limits were determined to be in the range of 0.11–0.29 μg L−1 and 0.35–0.93 μg L−1. The relative standard deviations for six replicates of organochlorine pesticides were in the range of 4.4%–7.2% and 5.7%–10.1% for one fiber and fiber-to-fiber, respectively. By coupling with a gas chromatography–electron capture detector, the novel fiber was successfully used for the determination of organochlorine pesticides in juice and milk samples with recoveries of 76.1%–121.3%.