Spectrofluorimetric Determination of Second Critical Micellar Concentration of SDS and SDS/Brij 30 Systems

• Published in: Journal of fluorescence Vol. 19; no. 2; pp. 327 - 332
• Main Authors: Romani, Ana Paula, da Hora Machado, Antonio Eduardo, Hioka, Noboru, Severino, Divinomar, Baptista, Mauricio S., Codognoto, Lúcia, Rodrigues, Maira R., de Oliveira, Hueder Paulo Moisés
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-03-2009
• Subjects: Acridine Orange; Analytical Chemistry; Biochemistry; Biological and Medical Physics; Biomedical and Life Sciences; Biomedicine; Biophysics; Biotechnology; Equivalence; Fluorescence; Fluorometry - methods; Media; Micelles; Oranges; Original Paper; Polyethylene Glycols - chemistry; Sodium Dodecyl Sulfate - chemistry; Surface-Active Agents - chemistry; CMC; Fluorescence; SDS; Dyes; Brij-30
• ISSN: 1053-0509; 1573-4994
• DOI: 10.1007/s10895-008-0420-4

Potentially useful stead-state fluorimetric technique was used to determine the critical micellar concentrations (CMC
1
and CMC
2
) for two micellar media, one formed by SDS and the other by SDS/Brij 30. A comparative study based on conductimetric and surfacial tension measurements suggests that the CMC
1
estimated by the fluorimetric method is lower than the value estimated by these other techniques. Equivalent values were observed for SDS micelles without Brij 30 neutral co-surfactant. The use of acridine orange as fluorescent probe permitted to determine both CMC
1
and CMC
2
. Based on it an explanation on aspects of micelle formation mechanism is presented, particularly based on a spherical and a rod like structures.