title: [High-performance liquid chromatography-electrospray ionization/tandem mass spectrometry of isofraxidin in Sarcandra glabra].
abstract: OBJECTIVE
  To establish a method for determining isofraxidin concentrations in Sarcandra glabra and Qingrexiaoyanning capsules with high-performance liquid chromatographic-mass spectrometry.
  
  
  METHODS
  Isofraxidin was extracted from Sarcandra glabra and Qingrexiaoyanning capsules with acetic ether and chloroform, respectively, and separated by isocratic reversed-phase chromatography. The mass spectrometric system was operated in multiple reaction monitoring mode. A pair of ions: precursor ion m/z 223 with product ion m/z 162 were chosen for the quantification of the analyte.
  
  
  RESULTS
  The retention time of isofraxidin was 6.60 min, and the calibration curve was linear over a concentration range from 484 to 9 680 ng/ml. The average recovery was 96.7% and RSD 4.49%, with detection limit of 1 ng/ml.
  
  
  CONCLUSIONS
  The method is rapid, selective and sensitive for determining isofraxidin in Sarcandra glabra and Qingrexiaoyanning capsules.
authors.affiliation: Central Laboratory, Southern Medical University, Guangzhou 510515, China. luoqizhi@fimmu.com
authors.forename: Qi-zhi
authors.initials: QZ
authors.lastname: Luo
authors.forename: Kai-jin
authors.initials: KJ
authors.lastname: Dai
authors.forename: An-de
authors.initials: AD
authors.lastname: Ma
mesh_terms: D002214:Capsules; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003374:Coumarins / Q000032:analysis*; D004365:Drugs, Chinese Herbal / Q000737:chemistry; D019684:Magnoliopsida / Q000737:chemistry*; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D002214:Capsules; D003374:Coumarins; D004365:Drugs, Chinese Herbal; C008182:isofraxidin