title: Efficient combination of circulating ultrasound-assisted extraction and centrifugal partition chromatography for extraction and on-line separation of chemical constituents from Stellera chamaejasme L.
abstract: BACKGROUND
  Sample preparation is a crucial step in medicinal herb analysis because the desired chemical components need to be extracted from the herbal materials for further separation and characterisation. Thus, the development of " modern" sample preparation techniques with significant advantages over conventional methods is very important.
  
  
  OBJECTIVE
  The aim of this study was the development of a new preparation method using circulating ultrasonic-assisted extraction (CUAE) coupled with centrifugal partition chromatography (CPC) for continuous extraction and on-line isolation of chemical constituents from Stellera chamaejasme L.
  
  
  METHODS
  The stationary or mobile phase was used as the extraction solvent. Extraction parameters, including the ultrasound power, extraction time, temperature, and liquid:solid ratio, were optimised using a response surface methodology.
  
  
  RESULTS
  The extraction time, temperature, and power considerably affected the extraction yield. The optimised extraction parameters were an ultrasound power of 800 W, extraction time of 30 min, extraction temperature of 70 °C, and liquid:solid ratio of 8 mL/g. The solvent system for CUAE and CPC was optimised using mathematical equations, and the two-phase solvent system of n-hexane:ethyl acetate:methanol:water at a volume ratio of 3:5:4:6 was calculated. Four target compounds (daphnoretin, chamaechromone, neochamaejasmin A, and isochamaejasmin) with purities above 96% were successfully extracted and isolated on-line via CUAE/CPC.
  
  
  CONCLUSIONS
  Compared with the reference extraction methods, the instrumental setup achieved a scientific and systematic extraction and isolation of natural products and has great potential for industrial application.
authors.affiliation: Central Laboratory, Changchun Normal University, No. 677 North Changji Road, Erdao District, Changchun, 130032, China.
authors.forename: Yuchi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Central Laboratory, Changchun Normal University, No. 677 North Changji Road, Erdao District, Changchun, 130032, China.
authors.forename: Chunming
authors.initials: C
authors.lastname: Liu
authors.affiliation: Central Laboratory, Changchun Normal University, No. 677 North Changji Road, Erdao District, Changchun, 130032, China.
authors.forename: Yanjuan
authors.initials: Y
authors.lastname: Qi
authors.affiliation: Traditional Chinese Medicine Academy of Science of Jilin Province, No. 1745 Gongnong Road, Chaoyang District, Changchun, 130021, China.
authors.forename: Yuchun
authors.initials: Y
authors.lastname: Li
authors.affiliation: Central Laboratory, Changchun Normal University, No. 677 North Changji Road, Erdao District, Changchun, 130032, China.
authors.forename: Sainan
authors.initials: S
authors.lastname: Li
authors.affiliation: Central Laboratory, Changchun Normal University, No. 677 North Changji Road, Erdao District, Changchun, 130032, China.
authors.forename: Yuqi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Central Laboratory, Changchun Normal University, No. 677 North Changji Road, Erdao District, Changchun, 130032, China.
authors.forename: Junqi
authors.initials: J
authors.lastname: Ren
authors.affiliation: Central Laboratory, Changchun Normal University, No. 677 North Changji Road, Erdao District, Changchun, 130032, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Tang
mesh_terms: D000465:Algorithms; D002138:Calibration; D002498:Centrifugation / Q000379:methods; D005591:Chemical Fractionation / Q000295:instrumentation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D010936:Plant Extracts / Q000302:isolation & purification*; D015203:Reproducibility of Results; D012997:Solvents / Q000737:chemistry; D013010:Sonication / Q000379:methods*; D013696:Temperature; D029645:Thymelaeaceae / Q000737:chemistry*; D013997:Time Factors
chemical_list: D010936:Plant Extracts; D012997:Solvents
keywords: Circulating ultrasonic assisted dynamic extraction; Stellera chamaejasme L; centrifugal partition chromatography; mathematical equations; response surface methodology