Extraction and quantitative analysis of tropane alkaloids in Radix physochlainae by emulsion liquid membrane with tropine-based ionic liquid.

Emulsion liquid membrane (ELM) coupled with tropine-based ionic liquid was prepared and successfully adopted for the extraction and quantitative analysis of tropane alkaloids (TA) in Radix physochlainae. Effects of formation conditions of ELM were explored and then optimized; the ideal oil-water mass ratio was determined to be 1:2.5, chloroform, Span 80 and 0.05 mol L-1N-propyl-tropine hexafluorophosphate ([C3Tr][PF6]) aqueous solution were stirred for 30 min with the speed of 1500 r min-1. In order to extract and enrich TA with ELM efficiently, key factors related with their extraction efficiency such as stirring speed, volume of the extracts (feed solution), migration time and initial concentration of TA were systematically investigated. Under optimal conditions, 1.5 mL extracts containing 1.6 mg mL-1 of TA was stirred with ELM at 250 r min-1 for 5 min, the extraction efficiency of target alkaloid can reach 94.14%. Finally, the method could be used in quantitative analysis of TA in herbal material and patent medicine after demulsification. By comparison, application of ELM for the enrichment and quantitation of TA offers a more straightforward and effective strategy, which is expected to provide a meaningful reference for similar separation processes.