Microemulsion liquid chromatography

Use of HPLC with oil/water emulsion introduced to the mobile phase (microemulsion liquid chromatography, MELC) for quantification of simvastatin [31] and five impurities of paracetamol [32]... 

However, while using microemulsion as an eluent, it should be remembered that several factors such as concentration of surfactants, co-surfactants and organic phase, pH of the aqueous phase, column temperature can influence the resolution and retention of the compounds. The microemulsions described so far are based on sodium dodecyl sulphate, short-chain alcohols such as butanol and octanol and aqueous phase of different pH values [78, 159-161]. The utility of w/o microemulsions in the normal phase HPLC analysis has also been described [162]. The microemulsion liquid chromatography (MELC) has been used for resolution of several API such as paracetamol, loratidine, simvastatin, niacinamide, fosinoprilat from their impurities or degradants or metabolic products [159-162]. 

McEvoy, E., Donegan, S., Power, J. and Altria, K. 2007, Optimization and validation of a rapid and efficient microemulsion liquid chromatography (melc) method for the determination of paracetamol (Acetominophen) content in a suppository formulation. J. Pharm. Biomed. Anal. 44,137. 

Berthod, A., De Carvalho, M. (1992). Oil in water microemulsion as mobile phase in liquid chromatography. Anal. Chem. 64 2267-2272. 

Wong, K.S. (2003) The application of multiplexed microemulsion electrokinetic chromatography for the rapid determination of log Pow values for neutral and basic compounds. Liquid Chromatography and Gas Chromatography of North America, 21, 1078-1088. 

Alain Berthod received his PhD in 1979 from the University of Lyon. He took an assistant professor s position at the French National Center for Scientific Research (CNRS) working in electrochemistry. In 1983 he was promoted as associate professor and in 1993 as research director. He focused on the developing and the use of micellar solutions and microemulsions in chromatography. His interests lie in the separation of chiral molecules and enantiorecognition mechanisms. He has contributed to the development of the countercurrent chromatography technique that uses a sup-port-free liquid stationary phase. He was member of the editorial board of major analytical chemistry and chromatography journals. He is editor-in-chief of Separation Purification Reviews (Taylor Francis, Philadelphia, Pennsylvania). 

El-Sherbiny, D.T., El-Enany, N., Belal, F. and Hansen, S. (2007) Simultaneous determination of loratadine and desloratadine in pharmaceutical preparations using liquid chromatography with a microemulsion as eluent. /. Pharm. Biomed. Anal., 43, 1236-1242. 

Wilson I.D., Poole C.F., (Eds). Liquid chromatography Microemulsion based HPLC methods. Encyclopedia of Separation Science—Online Update ISBN 978-0-12-226770-3 (Elsevier, 2(X)7). 

The larger realms of microemulsion compositions were obtained with butanol as the cosurfactant. A continuous change between the LI, the bicontinuous, and the L2 structures, was observed as the amoimt of oil was increased in the system composition. With pentanol, the W/0 microemulsion domain, also called LI microemulsions, is separated from the 0/W (or L2) microemulsion domain. With hexanol as the cosurfactant, the W/0 or LI microemulsion is composed of swollen micelles with more than 99% of water, and only the L2 structure is observed with the three oils studied (Figure 2.18) [36]. Many microemulsion compositions have a viscosity higher than 5 cP, whieh is the maximum value for the viscosity of a mobile phase in liquid chromatography [35]. 

A. Berthed, O. Nicolas and M. Porthault, L2 Microemulsions as Mobile Phases in Liquid Chromatography, Anal Chem., 62 1402 (1990). 

A. Betthold, M. De Carvalho, Oil in water microemulsions as mobile phases in liquid chromatography, Arud. Chem., 1992, 64, 2267-2272. 

Microemulsion electrokinetic chromatography Micellar liquid chromatography Morphine Mass spectrometry... 

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