Micellar electrokinetic chromatography: A practical overview of current methodological and instrumental advances

This review highlights recent methodological and instrumental advances in MEKC focused on the improvement of this CE technique in routine analyses. As in the previous reviews, the present one deals with the last 2 years' most relevant methodological contributions for improving sensitivity and resolution in MEKC as well as instrumental research related to MS and LIF detection. The most widespread approaches are discussed in detail, including enhancements in sensitivity arising from the use of on-line sample concentration (stacking, sweeping, and a combination of both of these protocols) and improvements in resolution, obtained by changing the composition of the BGE (e.g. with additives to the aqueous phase or employing alternative micellar phases to classical SDS) and using 2-D separation systems. The advantages and restrictions in MS and LIF detection as applied to MEKC analysis are also examined, especially in the direct coupling of MEKC and MS detection. Finally, some thoughts on potential future directions are also considered.