RESUMEN
In this work, a "turn off-on" fluorescent sensor was developed for highly sensitive determination of tert-butylhydroquinone (TBHQ) based on an Fe(III)-based metal-organic framework (Fe-MOF). An Fe-MOF with an octahedral structure was synthesized via a simple hydrothermal method using ferric chloride hexahydrate and 2-aminoterephthalic acid (NH2-BDC) as raw materials. The fluorescence of Fe-MOF is extremely weak owing to ligand-to-metal charge transfer (LMCT) and internal filtration effect (IFE). When the system contained TBHQ, the binding of TBHQ to Fe(III) inhibited the LMCT of the fluorescent ligand NH2-BDC to Fe(III), releasing the fluorescence of NH2-BDC and thus restoring the fluorescence. With this as the basis, a rapid, sensitive, and selective fluorescence sensor is developed for the detection of TBHQ. Under the optimal conditions, TBHQ showed good linearity with fluorescence intensity in the range of 0-1.5 × 102 µmol L-1 and a detection limit of 0.0030 µmol L-1 (S/N = 3). The selectivity, reproducibility, and stability of the developed Fe-MOF-based sensors are comprehensively studied. Finally, the practicality of the method is verified by examining the detection of TBHQ in soybean oil; the results are consistent with those obtained using conventional high-performance liquid chromatography.
Asunto(s)
Colorantes , Compuestos Férricos , Ligandos , Reproducibilidad de los Resultados , AceitesRESUMEN
This study reports the development of a Tb-metal-organic framework (Tb-MOF)-based fluorescent platform for the detection of propyl gallate (PG). The Tb-MOF using 5-boronoisophthalic acid (5-bop) as the ligand exhibited multiple emissions at 490, 543, 585, and 622 nm under an excitation wavelength of 256 nm. The fluorescence of Tb-MOF was selectively and significantly weakened in the presence of PG due to the special nucleophilic reaction between the boric acid of Tb-MOF and o-diphenol hydroxyl of PG, and the combined effect of static quenching and internal filtering. Furthermore, this sensor enabled the determination of PG within seconds in a wide linear range of 1-150 µg/mL, and with a low detection limit of 0.098 µg/mL, and high specificity against other phenolic antioxidants. This work provided a new route for the sensitive and selective determination of PG in soybean oil, thus was perspective to monitor and reduce the risk of PG overuse.
Asunto(s)
Estructuras Metalorgánicas , Galato de Propilo , Límite de Detección , Colorantes Fluorescentes , AceitesRESUMEN
The peroxide value (PV) is an important indicator to assess quality of edible oils. However, traditional methods for determining PV are complicated for operating and lack sensitivity. In this paper, we report a fast, reusable, selective and sensitive room-temperature phosphorescence (RTP)-based sensor to determine the PV of edible oils. The sensor comprises a lead-based metal-organic framework (Pb-MOF, Pb4O(TPA)3, TPA: (terephthalic acid). Luminescence studies reveal that bright RTP of Pb-MOF quenched significantly by iodide ions (I-), a classic reductant for peroxides in edible oils, thus the determination of the PV is possible. Crucially, the proposed method yields responses within 10 min and has a wide linear range of 0.35-25.62 mmol/kg, a low detection limit of 30 µmol/kg, and high selectivity for PV detection. The sensing system was successfully applied to determine the PVs of edible oils and monitor the PV of rapeseed oil during storage.