Micelle exclusion chromatography

This technique has found limitations in the determination of bromide mixed halides, iodide, iodate, nitrite, nitrate, sulphide, sulphite, thiocyanate, thiosulphate and isobutyrate in non saline waters. 

The method is based on the partitions of the anions to a cationic micelle phase and shows different selectivity from ion exchange chromatography. In a kinetic method [13] for the determination of thiocyanate, sulphite and sulphide the anions are reacted with 5,5 dithiobis (2-nitrobenzoic acid) in aqueous cetyltrimethyl/ammonium bromide micelles. 

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Dietrich et al. [7] applied micelle exclusion chromatography to the determination of iodate, nitrite, nitrate, bromide and iodide in non saline waters. 

T. Okada, Micelle Exclusion Chromatography of Inorganic Anions, Anal Chem., 60 1511 (1988). 

A. Piccolo, S. Nardi, and G. Concheri, Micelle-like conformation of humic substances as revealed by size exclusion chromatography. Chemosphere 33 595 (1996). 

Size-exclusion chromatography (SEC) has been used to characterize the unimer-micelle distribution. However, SEC is not an absolute method and thus requires calibration. Since it is practically impossible to calibrate a SEC apparatus for the unimers and micelles formed by a block copolymer, only indicative MW values can be obtained. Moreover, several authors have noted a strong perturbation of the unimer-micelle equilibrium during SEC experiments even when interaction of the material with the SEC column was minimized [4,61,62],... 

Polysorbate 80 is widely used as a nonionic surfactant in liquid pharmaceutical products such as inhalation, suspension, and nasal suspension products, due to its properties of solubilization, reduction of surface and interfacial tension, and wetting. Direct analysis of Polysorbate 80 is quite time consuming. Size-exclusion chromatography (SEC) has been reported [5] in which a mobile phase contained the surfactant at concentrations above the critical micelle concentration. Polysorbate 80 appeared as a very broad peak and coeluted with other peaks, which makes quantification in Nasonex impossible. 

Varga, B., Kiss, G., Galambos, I., Gelencser, A., Hlavay, J., and Krivacsy, Z. (2000). Secondary structure of humic acids. Can micelle-like conformation be proved by aqueous size exclusion chromatography Environ. Sci. Technol. 34,3303-3306. 

Desjardins A, Eisenberg A. Colloidal properties of block iono-mers. 1.4 Characterization of reverse micelles of styrene-b-metal methacrylate diblocks by size-exclusion chromatography. Macromolecules 1991 24 5779-5790. 

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