Ultrafast Sodium Dodecyl Sulfate Micellar Electrokinetic Chromatography with Very Acidic Running Buffers

• Published in: Analytical chemistry (Washington) Vol. 74; no. 1; pp. 257 - 260
• Main Authors: Rodríguez-Delgado, Miguel A, Garcia-Montelongo, Francisco J, Cifuentes, Alejandro
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.01.2002
• Subjects: Acids; Analytical chemistry; Biological Factors - analysis; Buffers; Chemistry; Chromatographic methods and physical methods associated with chromatography; Chromatography; Electrophoresis, Capillary - methods; Exact sciences and technology; Food Analysis; Hydrogen-Ion Concentration; Micelles; Other chromatographic methods; Sodium; Sodium Dodecyl Sulfate; Sulfur; Time Factors; Performance evaluation; Micellar electrokinetic capillary chromatography; Sodium compound; Optimization; Lauryl sulfate; Operating conditions; Anionic surfactant; Separation method; Polyphenol; Ultraviolet detector; Analysis method; Organic sulfate; Benzenic compound
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac010838k

A new micellar electrokinetic chromatography (MEKC) procedure has been developed that allows the use of the anionic surfactant sodium dodecyl sulfate (SDS) together with separation buffers at pHs as low as 1. The technique is based on the employment of a high molecular weight polyethylenimine (PEI)-coated capillary that provides strong cathodal electroosmotic flows at acidic pHs when SDS is added to the running buffer. The procedure is easy to implement since the capillary coating is done by just flushing a PEI aqueous solution through the capillary and the subsequent steps are the same as those for any MEKC protocol. Moreover, the coating renewal provides reproducible separations between injections (migration time RSD values lower than 1.82 and 3.44% were obtained for the same day and three different days, respectively). The good possibilities of this system are demonstrated by showing the separation of a group of eight polyphenolic compounds within a separation time shorter than 2 min. This procedure allows one to extend the optimization of SDS-MEKC separations to the very acidic pH range too.