Skip to main content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Simultaneous Concentration and Separation of Coumarins Using a Molecular Micelle in Micellar Affinity Gradient Focusing



Mary W. Kamande, David J. Ross, Laurie E. Locascio, Mark Lowry, Isiah M. Warner


We report the use of a molecular micelle for the simultaneous separation and concentration of neutral and hydrophobic analytes using micellar affinity gradient focusing (MAGF). The technique, MAGF, combines the favorable features of micellar electrokinetic chromatography (MEKC) and temperature gradient focusing (TGF). The focusing of neutral coumarin analytes was accomplished by the use the molecular micelle, poly (sodium undecenyl sulfate), poly-SUS. Concentration enhancements of 10-fold to 25-fold per minute were achieved for focusing of the coumarin dyes. The effect of varying the temperature gradient on the resolution of 2 of the coumarins dyes was also investigated, demonstrating that improved resolution could be achieved by reducing the steepness of the temperature gradient. In addition, with scanning-mode MAGF (in which the peaks are sequentially scanned past a fixed detection point by varying the buffer counter-flow velocity), the use of poly-SUS was shown to produce repeatable and quantitative analyte peaks, making quantitative separations possible with the MAGF technique. Finally, it was shown that peak areas could be increased in scanning MAGF by reducing the scan rate so that the sensitivity of the method can be adjusted as needed.
Analytical Chemistry


capillary electrophoresis, micellar electrokinetic chromatography, molecular micelles, temperature gradient focusing
Created March 1, 2007, Updated February 17, 2017