Biphasic recognition enantioseparation of ofloxacin enantiomers by an aqueous two‐phase system

BACKGROUND Our previous study indicated that monophasic recognition enantioseparation based on an aqueous two‐phase system ( ATPS ) is restricted because of its relatively low enantioselectivity. To improve the enantioselectivity, biphasic chiral selectors could be introduced into the ATPS . This work has focused on ATPS technology utilizing cooperation of L ‐tartaric acid ( L ‐ TA ) with hydroxypropyl‐ β ‐cyclodextrin ( HP ‐ β ‐ CD ), for the biphasic recognition enantioseparation of ofloxacin ( OFLX ) enantiomers. RESULTS Under the optimum conditions, namely PEG2000 mass fraction of 40% (w/w), ammonium sulfate mass fraction 25% (w/w), pH value 4, HP ‐β‐ CD concentration 0.02 mol L −1 , L ‐ TA concentration 0.05 mol L −1 , separation factor ( α ) reached 1.32 after just one‐step extraction. Furthermore, for the purpose of explaining the extraction behavior, a reasonable enantioselective extraction mechanism was also proposed. CONCLUSION The novel biphasic recognition extraction based on ATPS presented in this work has the ability for good enantioseparation of OFLX enantiomers. © 2014 Society of Chemical Industry