Abstract:

A method for the separation and determination of optical isomers of phenylephrine was developed based on the promoting effect of non-chiral ionic liquid on chiral ligand-exchange capillary electrophoresis after the electrophoretic parameters were optimized systematically. R-phenylephrine and S-phenylephrine can be separated and determined effectively in 20 mmol/L Tris-H₃PO₄ buffer solution (pH 5.4) composed of 4.0 mmol/L Cu(Ⅱ), 8.0 mmol/L L-proline (L-Pro) and 15 mmol/L 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) with the applied voltage of 20 kV, capillary temperature of 25 ℃, detection wavelength of 254 nm, and injection of 5 s at 3447 Pa. The resolution of R- and S-phenylephrines was 1.42. The linear ranges for the determination of R-phenylephrine and S-phenylephrine were 12.5-150 mg/L and 15.0-150 mg/L, respectively. The method has been satisfactorily used for the determination of R-phenylephrine and S-phenylephrine in the spiked blood and urine samples. The spiked recoveries in the urine sample were in the range of 93.7%-108.2% with the RSDs lower than 3.18%(n=3), and the spiked recoveries in the blood sample were in the range of 91.4% and 113.1% with the RSDs lower than 4.82%(n=3).

Key words: capillary electrophoresis, chiral ligand exchange, chiral separation, ionic liquid, optical isomers, phenylephrine