This study was investigated for the enantioselective separation of (S)-ibuprofen using the ionic liquid in the microfluidic device. A stable and thin ionic liquid flow (ILF) was made by controlling the flow rate of the ELF in the microfluidic channel. In addition, coupling lipase as a biocatalyst with the ILF based on the microfluidic device showed the facilitative and selective transport of (S)-ibuprofen across the ILF, indicating successful optical resolution of a racemic mixture. Subsequently, the enantioselectivity was evaluated in the transport ratio (q) of (R)- and (S)-ibuprofen, the optical resolution ratio (alpha) and enantiomeric excess of (S)-ibuprofen (ee(S)). (c) 2006 Elsevier B.V. All rights reserved.