Enantioseparation of basic chiral drugs on a carbamoylated erythromycin-zirconia hybrid monolith using capillary electrochromatography

• A carbamoylated erythromycin-incorporated zirconia hybrid monolithic (ERY-ZHM) column was prepared.
• The ERY-ZHM column was used for enantioseparation of basic chiral drugs by CEC.
• Optimal conditions for chiral separations on the ERY-ZHM were investigated.

An organic–inorganic hybrid monolithic column was prepared within the confines of a capillary via a single-step in situ sol–gel approach using zirconium tetrabutoxide as a precursor to compose the inorganic backbone and 3-triethoxysilylpropyl carbamoylated derivative of erythromycin (TEOSPC-ERY) as a co-precursor to introduce the organic chiral selector moiety in the zirconia backbone. The resulting carbamoylated ERY-zirconia hybrid monolith (ERY-ZHM) showed homogeneous morphology with well-defined through pores and was tightly connected with the inner wall of the capillary. The column was employed for capillary electrochromatographic enantioseparation of six basic chiral drugs in mobile phases (MPs) consisting of acetonitrile (ACN) and triethylammonium acetate (TEAA) buffer. The effects of composition of MP and applied voltage on chiral separation were investigated by using propranolol as a representative analyte. The highest resolution (Rs = 3.33) was obtained with a MP consisting of 10/90 (v/v) ACN/TEAA buffer (10 mM, pH 7), 10 kV applied voltage and 25 °C capillary temperature. The relative standard deviations for resolution values regarding run to run, day to day, column to column and batch to batch repeatability were 0.41%, 0.89%, 1.80% and 2.26% (for n = 3), respectively, indicating satisfactory stability of columns and reproducibility of column preparation process.