Macromolecular surfactant as a pseudo-stationary phase in micellar electrokinetic capillary chromatography

We examined polymers of sodium 11-acrylamidoundecanoate [poly(Na 11-AAU)] w ith a very high molecular mass (>10(6)) for their potential use as a pseudo -stationary phase in micellar electrokinetic capillary chromatography (MEKC ). Size-exclusion chromatography and capillary electrophoresis studies reve al that the polymers are highly charged, and have a densely packed chain st ructure. For aromatic compounds, the polymeric surfactant showed significan tly different selectivity than sodium dodecyl sulfate (SDS). It was suggest ed that one molecule of poly(Na 11-AAU) forms one micelle. The structural s tability of this pseudo-stationary phase permitted its use with relatively high percentages of organic modifiers in the buffer medium, allowing the se paration of highly hydrophobic compounds which are difficult to analyze by conventional MEKC with SDS. (C) 2000 Elsevier Science B.V. All rights reser ved.