| Based on the molecular alcohol aqueous two-phase system and the ionic liquid aqueous two-phase system,the new method of using n-propanol and hydrophilic ionic liquid（1-butyl-3-methylimidazolium tetrafluoroborate,［Bmim］BF4 ） with （NH4）2SO4 binary aqueous two phase system for the extraction of doxycycline hydrochloride was developed.The influence factors on partition behaviors of doxycycline hydrochloride were studied,including concentration of （NH4）2SO4,n-propanol consumption,pH value,concentration of ionic liquid and doxycycline hydrochloride.The results showed that when using pH value of 4.0-5.0,（NH4）2SO4 concentration of 34% and doxycycline hydrochloride concentration between 25-95 mg/L,the extraction rate and distribution coefficient of doxycycline hydrochloride will be up to 90.26%-95.71% and 62.452-149.401,respectively. |