| Abstract: | Potential possibilities of long‐chain ionic liquids based on imidazole (1‐dodecyl‐3‐methylimidazolium chloride and 1‐cetyl‐3‐methylimidazolium chloride) for online sample concentration techniques (field‐amplified sample stacking, head‐column field‐amplified sample stacking, and sweeping) of catecholamines were studied in both capillary zone electrophoresis and micellar electrokinetic chromatography. The use of a high‐conductivity sample matrix in sweeping was found to significantly increase the separation efficiency of analyte up to 2 × 106 theoretical plates per meter and remarkably reduce limits of detection for catecholamines up to 50 ng/mL. This approach was shown to be suitable for the determination of trace amounts of catecholamines in biological fluids. |
