Effects of static quenching and light pulse intensity on the time-dependent fluorescence quenching kinetics

1994 ◽  
Vol 179 (1) ◽  
pp. 23-37 ◽  
Author(s):  
Jaeyoung Sung ◽  
Kook Joe Shin ◽  
Sangyoub Lee
Keyword(s):  
Fluorescence Quenching ◽  
Light Pulse ◽  
Time Dependent ◽  
Static Quenching ◽  
Pulse Intensity

A Fluorescence Quenching Analysis of the Binding of Fluoroquinolones to Humic Acid

2017 ◽  
Vol 71 (11) ◽  
pp. 2512-2518 ◽  
Author(s):  
Ryan P. Ferrie ◽  
Gregory E. Hewitt ◽  
Bruce D. Anderson
Keyword(s):  
Humic Acid ◽  
Fluorescence Quenching ◽  
Water Solubility ◽  
Binding Constants ◽  
High Water ◽  
Static Quenching ◽  
Temperature Range ◽  
Equilibrium Binding ◽  
Quenching Analysis ◽  
High Water Solubility

Fluorescence quenching was used to investigate the interaction of six fluoroquinolones with humic acid. Static quenching was observed for the binding of ciprofloxacin, enoxacin, fleroxacin, levofloxacin, norfloxacin, and ofloxacin to humic acid. The equilibrium binding constants were found from Stern–Volmer plots of the data. The quenching experiments were repeated over a temperature range of 25–45 ℃ and van’t Hoff plots were generated. From these linear plots, thermodynamic values were calculated for Δ H, Δ G, and Δ S for each of the fluoroquinolones. The equilibrium binding constants were found to be <1 for all the antibiotics studied. The calculated ΔH values were all negative and ranged from −9.5 to −27.6 kJ/mol. The high water solubility of the antibiotics and low ΔH of binding suggests that the antibiotics will be transported easily through the environment. Finally, whether the fluoroquinolones are in a protonated, deprotonated, or partially protonated state is found to correlate to the strength of binding to humic acid.

A study on fluorescence quenching of a laser dye by aromatic amines in alcohols

2015 ◽  
Vol 93 (4) ◽  
pp. 469-474 ◽  
Author(s):  
H.R. Deepa ◽  
J. Thipperudrappa ◽  
H.M. Suresh Kumar
Keyword(s):  
Fluorescence Quenching ◽  
Aromatic Amines ◽  
Room Temperature ◽  
Static Quenching ◽  
Laser Dye ◽  
Approximation Model ◽  
Positive Deviation ◽  
Quenching Rate ◽  
Time Resolved ◽  
Bimolecular Quenching

The fluorescence quenching of 1,2,3,8-tetrahydro-1,2,3,3,8-pentamethyl-5-(trifluoromethyl)-7H-pyrrolo[3,2-g]quinolin-7-one (LD-473) by aromatic amines, namely, aniline, dimethyl aniline, and diethyl aniline, in methanol, ethanol, propanol, and butanol has been studied at room temperature using steady-state and time-resolved methods. A positive deviation from linearity has been observed in Stern–Volmer (S–V) plots. Various quenching rate parameters have been determined using the extended S–V equation and are found to be dependent on the dielectric constant of alcohols. The quenching ability of amines increases with increasing their ionization energies. Further, with the use of the sphere of action, static quenching model, and finite sink approximation model, it is concluded that the bimolecular quenching reactions are due to the combined effect of both dynamic and static quenching processes.

scholarly journals Fluorescence Quenching of DMB by Aniline in Benzene-Acetonitrile Mixture

2016 ◽  
Vol 65 ◽  
pp. 32-36 ◽  
Author(s):  
Ashok H. Sidarai ◽  
Vani R. Desai ◽  
Shirajahammad M. Hunagund ◽  
Mahantesha Basanagouda ◽  
Jagadish S. Kadadevarmath
Keyword(s):  
Fluorescence Quenching ◽  
Room Temperature ◽  
Solvent Mixture ◽  
Static Quenching ◽  
Solvent Mixtures ◽  
Dynamic Quenching ◽  
Approximation Model ◽  
Positive Deviation ◽  
Coumarin Dye ◽  
Static And Dynamic Quenching

The fluorescence quenching of coumarin dye namely 4-(2,6-dibromo-4-methyl-phenoxymethyl)-benzo[h]chromen-2-one [DMB] has been studied by aniline, in a different solvent mixture of benzene (BN) and acetonitrile (AN) at room temperature. The quenching is found to be appreciable and shows positive deviation from linearity in the Stern-Volmer (S-V) plots for all the solvent mixtures. The various rate parameters responsible for fluorescence quenching have been determined using a sphere of action static quenching model and finite sink approximation model. The magnitudes of these rate parameters indicate that positive deviation in the S-V plot is due to both static and dynamic quenching processes.

Effect of fluorescence quenching on 6BAAC in different solvents

2014 ◽  
Vol 92 (1) ◽  
pp. 41-45 ◽  
Author(s):  
N.R. Patil ◽  
R.M. Melavanki
Keyword(s):  
Fluorescence Quenching ◽  
Empirical Relation ◽  
Static Quenching ◽  
Einstein Relation ◽  
Positive Deviation ◽  
Quenching Rate ◽  
R And D ◽  
Diffusion Limited ◽  
Quenching Mechanisms ◽  
Static And Dynamic Quenching

The fluorescence quenching studies of 6-bromo-3-azidoacetyl coumarin (6BAAC) by aniline in four different solvents, namely acetonitrile, benzene, dioxane, and toluene, were carried out at room temperature to understand quenching mechanisms. The Stern–Volmer plots have been found to be nonlinear with a positive deviation for all the solvents studied. To interpret these results we have invoked the ground state complex formation and sphere of action static quenching models. Using these models various quenching rate parameters have been determined. The magnitudes of these parameters suggest that the sphere of action static quenching model agrees well with the experimental results. Hence the positive deviation is attributed to the static and dynamic quenching. Further, with the use of the finite sink approximation model, it was possible to check these bimolecular reactions as diffusion-limited and to estimate independently distance parameter R′ and mutual diffusion coefficient D. Finally an effort has been made to correlate the values of R′ and D with the values of the encounter distance R and the mutual coefficient D determined using Edward’s empirical relation and the Stokes–Einstein relation.

scholarly journals Light-Evoked and Spontaneous Discrete Waves in the Ventral Nerve Photoreceptor of Limulus

1973 ◽  
Vol 61 (5) ◽  
pp. 552-571 ◽  
Author(s):  
Stephen Yeandle ◽  
Joel B. Spiegler
Keyword(s):  
Light Pulse ◽  
Visual Pigment ◽  
Time Dependent ◽  
Photon Absorption ◽  
Short Pulses ◽  
Short Light Pulse ◽  
Pigment Molecule ◽  
The Waves ◽  
Ventral Nerve Photoreceptor

Discrete waves, recorded from the ventral nerve photoreceptor, occur in the light and in the dark. Spontaneous waves, on the average, are smaller than light-evoked waves. This suggests that not all spontaneous waves can arise from spontaneous changes in the visual pigment molecule identical to changes induced by photon absorption. Spontaneous and light-evoked waves are statistically independent of each other. This is shown by determination of frequency of response as a function of pulse energy for short pulses and determination of the distribution of intervals between waves evoked by steady lights. The available data can be explained by two models. In the first each photon produces a time-dependent excitation that goes to zero the instant the wave occurs so that the number of effective absorptions from a short light pulse equals the number of waves produced by the light pulse. In the second the excitation produced by photon absorption is unaffected by the occurrence of the waves so that the number of waves produced from a short light pulse may be different from the number of effective absorptions. Present results do not allow a choice between the two models.

scholarly journals Solvent Effect on Fluorescence Quenching of 7, 8 Benzo‑4‑azido Methyl Coumarin by Aniline

2013 ◽  
Vol 12 (1) ◽  
pp. 69-85 ◽  
Author(s):  
R M Melavanki ◽  
N R Patil ◽  
D Nagaraja ◽  
H D Patil ◽  
J S Kadadevarmath ◽  
...  
Keyword(s):  
Fluorescence Quenching ◽  
Empirical Relation ◽  
Biologically Active ◽  
Static Quenching ◽  
Einstein Relation ◽  
Positive Deviation ◽  
Quenching Rate ◽  
R And D ◽  
Diffusion Limited ◽  
Static And Dynamic Quenching

Fluorescence quenching of biologically active studies of 7, 8 benzo-4-azidomethyl coumarin (7BAMC) by aniline in four different organic solvents namely benzene, dioxane, tetrahydrofuran and acetonitrile has been carried out at room temperature with a view to understand the quenching mechanisms. The Stern–Volmer (S-V) plot has been found to be non-linear with a positive deviation for all the solvents studied. In order to interpret these results we have invoked the ground state complex formation and sphere of action static quenching models. Using these models various quenching rate parameters have been determined. The magnitudes of these parameters suggest that sphere of action static quenching model agrees well with the experimental results. Hence the positive deviation is attributed to the static and dynamic quenching. Further, with the use of Finite Sink approximation model, it was possible to check these bimolecular reactions as diffusion-limited and to estimate independently distance parameter R’ and mutual diffusion coefficient D. Finally an effort has been made to correlate the values of R’ and D with the values of the encounter distance R and the mutual coefficient D determined using the Edward’s empirical relation and Stokes – Einstein relation.

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