Spectroscopic determination of Critical Micelle Concentration in aqueous and non-aqueous media using a non-invasive method

• Published in: Journal of colloid and interface science 2011-12, Vol.364 (2), p.400-406
• Main Authors: Anand, Uttam, Jash, Chandrima, Mukherjee, Saptarshi
• Format: Article
• Language: English
• Subjects: Chemistry; Colloidal state and disperse state; Critical Micelle Concentration; Distortion; Exact sciences and technology; fluorescent dyes; General and physical chemistry; Media; Methodology; Micelles; Micelles. Thin films; Non-invasive techniques; octoxynol; Perturbation methods; Phenyls; Spectroscopy; Steady-state and time-resolved spectroscopy; surfactants; Triton
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2011.08.047

The figure and the inset represent the change of fluorescence peak intensity with increasing [TX-100] in water and cyclohexane, respectively measured by non-invasive method. The CMC of TX-100 can be estimated from the break point of the graphs. [Display omitted] ► CMC of TX-100 determined by non-invasive methodology. ► Micellar and Reverse Micellar systems characterized. ► Structural perturbations induced by external fluorophores avoided. ► Steady-state and time-resolved measurements are highly correlated. ► Three external probes used also support the non-invasive technique. In this present study, we report on new methodology for determining the Critical Micelle Concentration (CMC) of a neutral surfactant Triton X-100 (TX-100) both in aqueous and non-aqueous media based on a non-invasive approach. The presence of the phenyl moiety of TX-100 was made use of as an intrinsic fluorophore and steady-state and time-resolved spectroscopy has been used to characterize the micellar systems. There are reports that external fluorophores may bring about some structural changes in the systems and the perturbations caused by these fluorophores in micellar systems may affect the shape and size of the micelles. We have also used three probes namely ANS, Rh6G and C-480 to determine the CMC of TX-100 both in aqueous and non-aqueous media and the values obtained agree very well with those estimated by the non-invasive techniques. Interestingly, for our system, we have conclusively proved that the external probes have almost no effect on the process of micellization. Although, both the invasive and non-invasive technologies report almost the same values of CMC, yet the latter methodology is free from any external perturbations and this makes the micellar/reverse micellar system, which may interact with other biological systems less prone to any physical distortions.