Absorption and emission spectroscopic studies of fluorescein dye in alkanol, micellar and microemulsion media

Fluorescence resonance energy transfer—a spectroscopic probe for organized surfactant media

“…The spectral shift observed for all the three dyes in their absorption and/or emission spectra indicate that the microenvironment around the dyes in micelles and reverse micelles is altered from that in neat water. Previous studies using other surfactants also support this fact [20][21][22]. The λ max abs value indicates that FL exists as the dianion.…”

Compromise between compactness of micelle and overlap integral toward Förster resonance energy transfer from an indoloquinoline derivative to fluorescein: A fluorometric study

“…This dual process increases the overlap integral for the FRET pair. As has been mentioned earlier that FL interacts with the anionic micelles through hydrophobic interaction and thus has lower binding constant than that with the CTAB micelles [32], hence the destabilization will be much lesser compared to that in the case of CTAB micelles. At the same time, considering the donor attachment to the anionic micellar surface through the localized positive charge on the N-atom of the quinonoid ring, it can be presumed that the destabilization of the donor will also be more.…”

“…This is necessary for the FRET process in the experiment as FL is an anionic molecule and interacts with the cationic CTAB micelle in a more facile way compared to that with the anionic micelles [32]. In the latter case, it is the hydrophobic interaction that plays the major role.…”

Quenching of fluorescence of 1-hydroxypyrene-3,6,8-trisulfonate (HPTS) by Cu2+, Co2+, Ni2+, I−, and cetylpyridinium (CP+) ions in water/AOT/heptane microemulsion

“…In the present system, both the fluorophore and the quenchers resided in the interior of the waterpool of the microemulsion, so that the interaction propensity was essentially guided by the fluidity of the core water, which increased with increasing ω, resulting in a concomitant increase in both K SV and k q which maximized at ω = ∞. At low ω, the solvation of interfacially adsorbed AOT molecules in the water pool (to the extent of 1:6 as AOT:water) [34,35] fairly decreased the pool fluidity and hence reduced both K SV and k q . Table 1 The Stern-Volmer constant (K SV ), the collisional quenching rate constant (k q ), the molar transient volume (V ), and the radius of the quenching sphere of action (r) obtained from measurements of fluorescence quenching of HPTS f by different ions at 298 K Quencher a Ionic radius (nm) ω b K SV (dm 3 mol −1 ) c 10 9 k q (mol −1 dm 3 s −1 ) V (dm 3 mol −1 ) r (nm) d The quenching efficiency of the transition metal ions has been observed to follow the order Fe 2+ > Cu 2+ > Co 2+ > Ni 2+ > Mn 2+ in aqueous, water-polyethylene glycol, and aqueous nonionic micellar media [21][22][23].…”