Interaction of sodium dodecyl sulfate with the hydrophobic fluorescent probe, 2-p-toluidinylnaphthalene-6-sulfonate

Abstract

The critical concentration (cmc) of sodium dodecyl sulfate at various NaCl concentrations can be followed by the increasing fluorescent intensity of 2-p-toluidinylnaphthalene-6-sulfonate (TNS). The thermodynamic parameters of the interaction of TNS and the SDS micelle have been obtained. Binding is exothermic and involves a positive entropy change. The negative value of enthalpy predominately contributes to the negative free energy of binding between TNS and the SDS micelle. The salt (NaCl) increases the association constant between TNS and micelle of SDS by increasing the positive entropy change. The results suggest that the binding force between TNS and the micelle of SDS is hydrophobic. The nature of hydrophobic fluorescent probe binding with proteins is discussed.

Spectrophotometric and Thermodynamic Studies of Micellar Interaction of Surfactants withp-Nitrophenol

“…A slight perturbation in the spectral behavior can be due to lipophilicity. [38][39][40] The finding is in concordance with those of Hartley. [41] Similar observations were reported by Rohatgi-Mukherjee et al [20] and Moulik et al [42] in their spectroscopic investigations of dye-surfactant interactions.…”

Dye exchange in micellar solutions. Quantitative analysis of bulk and single molecule fluorescence titrations

“…The high sensitivity of this type of dyes to the solvent polarity and their moderate hydrophobicity make them a good choice for the determination of the cmc of micellar solutions. [44][45][46][47][48][49][50][51][52] Fig. 3 shows the emission spectra obtained from titrations of ANS with TX100 (thin grey curves).…”

Modulating properties of aqueous sodium dodecyl sulfate by adding hydrophobic ionic liquid

“…As a result, TNS has been routinely used to study aggregation processes in aqueous solutions [28,[117][118][119][120]. TNS λ max (panel A) and fluorescence intensity (panel B) as a function of [SDS] in the presence of six different additions of bmimPF 6 are recorded (Fig.…”