Highly fluorinated polymers are promising materials in separation methods due to their combination of high chemical and thermally stability, hydro- and oleophobicity, and weak intermolecular forces. However, application of these polymers in chromatography is limited because of their low solubility in aqueous-organic solvents. In our research, the highly fluorinated water soluble polymers with -SO3- N(Et)4+ , -SO2 NH2 , and -N(Et)2 terminal groups were synthesized and applied as additives to the background electrolyte for the separation of steroid hormones and proteins by capillary electromigration methods. It is shown that highly fluorinated polymers can be used both as pseudo-stationary phases in electrokinetic chromatography for high separation efficiency (N ∼ 200 × 103 ) and selectivity (α ∼ 1.1) of uncharged analytes (e.g., steroid hormones), and as dynamic modifiers of fused silica capillary walls. The highest separation efficiency (N ∼ 1 × 106 ) and selectivity (α ∼ 1.3) of steroid hormones was achieved by combination of sodium dodecyl sulfate and fluoropolymer with sulfonate groups in background electrolyte with pH 2. Dynamic wall coatings based on fluoropolymer with -SO2 NH2 (which are easier and faster to create and wash off) exhibit significantly higher separation efficiency and selectivity compared to capillary electrochromatography on capillary columns based on polymethacrylate polymers.
Keywords: capillary electrophoresis; highly fluorinated polymers; micellar electrokinetic chromatography; proteins; steroids.
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