Multifunction covalent coatings for separation of amino acids, biogenic amines, steroid hormones, and ketoprofen enantiomers by capillary electrophoresis and capillary electrochromatography

In this study, the preparation process of multifunctional coating based on imidazole and beta-cyclodextrin has been developed. The synthesis includes several steps: activation of fused silica capillary walls via alkali, then process of silylation and finally functionalization with imidazole and beta-cyclodextrin derivative. The latter step was carried over 22 h at 100 degrees C at 750 mg/mL concentration of p-toluenesulfonyl-beta-cyclodextrin. It was established that the coatings thus obtained are stable within pH 2-7 range but decompose in alkaline medium. The stationary phase developed in this study allows simultaneous separation of hydrophobic and hydrophilic analytes. Chiral separation of ketoprofen enantiomers was also achieved with the newly developed covalent coating. It was found that covalent coating based on imidazole and beta-cyclodextrin exceeded the dynamic coatings of similar structure in terms of repeatability, analysis time and the limits of detection.