			Home About us Contact

Micelle Systems (micelle + system)

Distribution by Scientific Domains

Chemistry	50%

Selected Abstracts

Determination of nucleic acid by [tetra-(3-methoxy-4-hydroxyphenyl)],Tb3+ porphyrin as the fluorescence spectral probe in bis(2-ethylhexyl)sulfosuccinate sodium salt micelle system

LUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 4 2009
Xin Chen
Abstract A new system for the determination of nucleic acid by rare earth metallic porphyrin of [tetra-(3-methoxy-4-hydroxyphenyl)],Tb3+ [T(3-MO-4HP),Tb3+] porphyrin as fluorescence spectral probe has been developed in this paper. Nucleic acid can enhance the fluorescence intensity of the T(3-MO-4HP),Tb3+ porphyrin in the presence of bis(2-ethylhexyl)sulfosuccinate sodium salt(AOT) micelle. In pH 8.00 Tris,HCl buffer solution, under optimum conditions, the enhanced fluorescence intensity is in proportion to the concentration of nucleic acids in the range of 0.05,3.00 µg mL,1 for calf thymus DNA (ct DNA) and 0.03,4.80 µg mL,1 for fish sperm DNA(fs DNA). Their detection limits are 0.03 and 0.01 µg mL,1, respectively. In addition, the binding interaction mechanism between T(3-MO-4HP),Tb3+ porphyrin and ct DNA is also investigated by resonance scattering and fluorescence spectra. The maximum binding number is calculated by molar ratio method. The new system can be used for the determination of nucleic acid in pig liver, yielding satisfactory results. Copyright © 2009 John Wiley & Sons, Ltd. [source]

The effect of co-surfactant-modified micelles on chiral separations in EKC

ELECTROPHORESIS, Issue 16 2009
Adeline B. Kojtari
Abstract The use of chiral pseudostationary phases in EKC provides high efficiencies and excellent resolution for enantiomeric separations. The chiral pseudostationary phases of interest in this study are alcohol-modified ("swollen") micelles, in which a co-surfactant (medium chain-length alcohol) is added with the surfactant. In this study, the chiral surfactant, dodecoxycarbonylvaline (DDCV), along with the co-surfactant, 2-hexanol, has been prepared as swollen micelle in order to investigate the chiral separation of enantiomeric pairs. Three sets of experiments were investigated in which swollen micelle systems contained: chiral surfactant and racemic co-surfactant; chiral surfactant and chiral co-surfactant; and phase ratio increases, in which both chiral surfactant and chiral co-surfactant were employed. In the first two sets of experiments, co-surfactant concentration was held constant and the surfactant concentration was increased. In the third set of experiments, both surfactant and chiral surfactant concentrations were increased proportionally. The chromatographic figures of merit for each enantiomeric pair were investigated and compared with various chiral aggregate systems. In swollen micelle compositions using constant racemic 2-hexanol concentration, when DDCV concentration increased, enantioselectivity and resolution increased; whereas, efficiency remained constant for most of the test compounds. Compositions using constant S -2-hexanol concentration reached a maximum in all chromatographic figures of merit when DDCV concentration was increased from 2 to 3%. An increase in both surfactant and co-surfactant concentrations led to noisy baselines and chiral aggregates that were generally unstable in solution. [source]

Non-aqueous reverse micelles media for the SNAr reaction between 1-fluoro-2,4-dinitrobenzene and piperidine,

JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 12 2006
N. Mariano Correa
Abstract The kinetics of the nucleophilic aromatic substitution (SNAr) reaction between 1-fluoro-2,4- dinitrobenzene (FDNB) and piperidine (PIP) in ethylene glycol (EG)/ sodium bis (2-ethyl-1-hexyl) sulfosuccinate (AOT)/n -heptane and dimethylformamide (DMF)/AOT/n -heptane non-aqueous reverse micelle systems is reported. EG and DMF were used as models for hydrogen bond donor (HBD) and non-hydrogen bond donor (non-HBD) polar solvents, respectively. The reaction was found not to be base catalyzed in these media. A mechanism to rationalize the kinetic results is proposed in which both reactants may be distributed between the two environments. The distribution constants of FDNB between the organic and each micellar pseudophases were determined by an independent fluorescence method. These results were used to evaluate the amine distribution constant and the intrinsic second-order rate coefficient of the SNAr reaction in the interface. The reaction was also studied in the pure solvents EG and DMF for comparison. The results in EG/AOT/n -heptane at Ws,=,2 give similar kinetic profiles than in water/AOT/n -hexane at W,=,10. With these HBD solvents, the interface saturation by the substrate is reached at around the same value of [AOT] and the intrinsic second-order rate coefficient in the interface, k,b, has comparable values. On the other hand, when DMF is used as a polar non-HBD solvent, the intrinsic second-order rate constant increases by a factor of about 200 as compared to the values obtained using HBD solvents as a polar core. It is concluded that higher catalytic power is obtained when non-HBD solvents are used as polar solvent in the micelle interior. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Fluorescence saturation of dye molecules in water pools of reversed micelles

LASER PHYSICS LETTERS, Issue 10 2005
A. V. Potapov
Abstract Rhodamine 6G has been used as a fluorescence probe in AOT reversed micelles systems with the different amounts of solubilized water (hydratation power ,). The saturation of fluorescence and the lifetime of dye molecules were measured. The absorption cross section values were calculated from the saturation curves. We showed the differences in values of the absorption cross section, lifetime and velocity of fluorescence saturation in micellar phase with different , and in comparison to bulk phase. Additionally, the structure of hydrated reversed micelles has been studied by the method of correlation spectroscopy. The influence of , on size and shape of micelles was detected. (© 2005 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]