Structural and fluorescence quenching characterization of hematite nanoparticles

Al-Kady, Ahmed S.; Gaber, Mohamed; Hussein, Mohamed; Ebeid, El-Zeiny M.

doi:10.1016/j.saa.2011.08.052

Cited by 61 publications

(32 citation statements)

References 70 publications

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“…Moreover, at all temperatures, the plots exhibit good linear relationships, which indicate that static quenching mechanisms dominate at the studied concentrations. The obtained quenching constants are similar to the results obtained for the fluorescence quenching of bovine serum albumin by Al 2 O 3 NPs and ZnO NPs , but smaller than the result reported for the interaction of iron oxide NPs with coumarin .…”

Section: Resultssupporting

confidence: 85%

Probing the interaction of caffeic acid with ZnO nanoparticles

2015

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The binding of ZnO nanoparticles (NPs) and caffeic acid (CFA) was investigated using fluorescence quenching, UV/vis absorption spectrscopy, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and dynamic light scattering (DLS) at different temperatures. The study results indicated fluorescence quenching between ZnO NPs and CFA rationalized in terms of a static quenching mechanism or the formation of non-fluorescent CFA-ZnO. From fluorescence quenching spectral analysis, the binding constant (K(a)), number of binding sites (n) and thermodynamic properties were determined. Values of the quenching (K(SV)) and binding (K(a)) constants decrease with increasing temperature and the number of binding sites n = 2. The thermodynamic parameters determined using Van't Hoff equation indicated that binding occurs spontaneously involving the hydrogen bond, and van der Waal's forces played a major role in the reaction of ZnO NPs with CFA. The FTIR, TEM and DLS measurements also indicated differences in the structure, morphology and size of CFA, ZnO NPs and their corresponding CFA-ZnO.

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Section: Resultssupporting

confidence: 85%

Probing the interaction of caffeic acid with ZnO nanoparticles

2015

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“…The recorded absorption bands at 446 and 545 cm −1 assigned to the Fe―O vibrational mode in α‐ Fe 2 O 3 powder that confirms the formation of α‐ Fe 2 O 3 .Whereas, the absorption bands at 900, 1100, 1628, and 2265 cm −1 are due to carbon dioxide, which generally absorbed to nanomaterials from the environment . The other absorption bands at 3428 cm −1 are assigned to the presence of hydrogen‐bonded OH groups . Figure shows FE‐SEM micrographs of the synthesized Fe 2 O 3 nanopowder.…”

Section: Resultsmentioning

confidence: 73%

Dielectric spectroscopic analysis of polyvinyl chloride nanocomposites loaded with Fe₂O₃ nanocrystals

Mansour

Elsad

Izzularab

2018

Polymers for Advanced Techs

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Iron oxide (α‐Fe2O3) nanocrystals powder was successfully synthesized via the sol‐gel method. The microstructural examination of the synthesized nanocrystals confirmed the formation of α‐Fe2O3 (hematite) structure using X‐ray diffraction and Fourier transform infrared. The synthesized nano‐hematite powder with different weight percentage up to 5 wt% was introduced to polyvinyl chloride (PVC) to fabricate PVC/Fe2O3 nanocomposites using the solution‐cast technique. The dielectric spectroscopic analysis for the investigated samples has been studied at room temperature and at different temperatures up to 120°C. The real part of the permittivity (ε′) exhibited a significant dependence on filler concentrations throughout whole temperature range. However, the dependency of both of the loss tangent (tanδ) and AC conductivity (σac) on filler concentrations is more pronounced at temperatures higher than room temperature. The obtained values of tan δ for the investigated nancomposites referred to the α‐relaxation around 70°C, which is close to glass transition temperature of the investigated PVC. The dependency of the dielectric strength on Fe2O3 nanofiller concentration was observed with enhancement in the dielectric strength reach to 20.5% for PVC/0.7 wt% Fe2O3 nanocomposite higher than the recorded value for the pristine PVC.

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“…4, which demonstrated that the quenching of 4-t-OP may be due to the simultaneous presence of dynamic and static quenching. The positive deviation phenomenon for S-V plots has been observed by many researchers [28, 29]. On the contrary, Naik and coworkers found that the S-V plot might show a negative deviation due to different conformations of anthrylyinyl acetate in the ground state [30].…”

Section: Resultsmentioning

confidence: 97%

“…Dynamic quenching refers to formation of an excited state fluorophore-quencher complex [27]. The dynamic process in which quenching mechanism is mainly due to collision is governed by the linear Stern-Volmer (S-V) equation as follows [28]:where I 0 and I are steady state fluorescence intensities in the absence and presence of quencher, respectively. Ksv and Kq are the S-V quenching constant and the bimolecular quenching constant, respectively.…”

Section: Resultsmentioning

confidence: 99%

Fluorescence Quenching of 4-tert-Octylphenol by Room Temperature Ionic Liquids and its Application

et al. 2012

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The interactions between room temperature ionic liquids (RTILs) and weak fluorescent chemicals still remain unclear, which hinders the complete and efficient utilization of these “green” solvents in fluorescent analyses of organic chemicals. Herein, we reported the effects of four RTILs, [C8MIM]BF4, [C14MIM]BF4, [C8MIM]PF6 and [C14MIM]PF6, on fluorescence behavior of 4-tert-octylphenol (4-t-OP). In the fortified concentration range of 0.2–1.0 mM, the quenching effects were increased with increasing concentrations of RTILs. However, no obvious variation of peak shape of 4-t-OP was observed in the quenching process, suggesting no formation of ground-state complex between fluorophores in 4-t-OP and quencher (ionic liquids). As for anion effect, the fluorescence quenching efficiency of 4-t-OP by BF4- was greater than PF6-, but the carbon chain length on the imidazolium ring had no significant relationship with fluorescence intensity of 4-t-OP. Both Ksv values (>1.0 × 103 L/mol.s) and the different temperature effects demonstrated that the quenching of 4-t-OP by four RTILs was the presence of dynamic and static quenching mechanism. The FI of dansyl chloride within [C8MIM]BF4 increased nearly 5-fold as compared to the control, showing a sensitizing effect on the strong fluorescent chemicals, while a quenching effect on 4-t-OP belonging to weak fluorescent chemicals. The fluorescence-enhanced amplitude of dansyl chloride in [C8MIM]PF6 was greater than [C8MIM]BF4. The fluorescence quenching of 4-t-OP by [C8MIM]PF6 did not belong to FRET phenomenon because of no overlap of emission spectrum of 4-t-OP and absorption spectrum of [C8MIM]PF6. When 0.6 mM [C8MIM]PF6 in acetonitrile was used as the solvent, the detection limit of 4-t-OP was 3.7 μg/L, and the linearity range was 0.01–0.8 mg/L (R2 = 0.9990). In summary, these results provide a theoretical foundation for the application of RTILs in weak fluorescent chemicals.

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Structural and fluorescence quenching characterization of hematite nanoparticles

Cited by 61 publications

References 70 publications

Probing the interaction of caffeic acid with ZnO nanoparticles

Probing the interaction of caffeic acid with ZnO nanoparticles

Dielectric spectroscopic analysis of polyvinyl chloride nanocomposites loaded with Fe₂O₃ nanocrystals

Fluorescence Quenching of 4-tert-Octylphenol by Room Temperature Ionic Liquids and its Application

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Structural and fluorescence quenching characterization of hematite nanoparticles

Cited by 61 publications

References 70 publications

Probing the interaction of caffeic acid with ZnO nanoparticles

Probing the interaction of caffeic acid with ZnO nanoparticles

Dielectric spectroscopic analysis of polyvinyl chloride nanocomposites loaded with Fe2O3 nanocrystals

Fluorescence Quenching of 4-tert-Octylphenol by Room Temperature Ionic Liquids and its Application

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Dielectric spectroscopic analysis of polyvinyl chloride nanocomposites loaded with Fe₂O₃ nanocrystals