Spectrophotometric Determination of Azithromycin by Aqueous Two-phase System Extraction from Mixture Containing ［Bmim］Cl, Propanol and K2HPO4

Azithromycin (AZMC) was separated from its solution by aqueous two-phase system extraction, using 1.0 mL of n-propanol and 0.5 mL of 1-butyl-3-methylimidazol hydrochloride as extraction solvent, and K2HPO4 (6.375 g) as phase-separating salt. The acidity of the upper phase was adjusted to pH 9.0, and the extraction was carried out at a temperature of 303.15 K. An aliquot of 1.0 mL each was taken from the upper and lower phase and phaced into 5 mL volumetric flasks separately, and to each of the flasks, 1.5 mL of 0.1 mol·L-1 HCl and 2.5 mL of H2SO4 (3+1) were added. Amounts of AZMC in both the solutions were determined spectrophotometrically at the wavelength of 481.5 nm (vs. reagent blank), by the HCl-H2SO4 method. Content of AZMC was found from the working curve. Rate of extraction was found attained to 89.71%.