title: Validated quantification method for five ephedrines in dietary supplements using LC-MS/MS: Application to 503 cases.
abstract: Ephedrines in dietary supplements can arise from herbs or illegal adulteration so a liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for separation and quantification of ephedrine, pseudoephedrine, norephedrine, norepseudoephedrine, and methyl-ephedrine, some of which are isomer pairs of pseudo-structures. This method includes liquid-liquid extraction of ephedrines from three typical dietary supplement matrices-solid, liquid, and oil-as well as liquid chromatographic separation. After liquid chromatographic separation, ephedrines are qualitatively and quantitatively analyzed using triple quadrupole mass spectrometry with positive electrospray ionization in multi-reaction monitoring (MRM) mode. Ephedrine recoveries in a solid matrix ranged from 53.3-91.5%, in a liquid matrix from 56.4-102.3%, and in an oil matrix from 51.7-01.2%. Linearity ranges were 10-1000ng/g in solid and oil matrix and 1-100ng/ml in liquid matrix. Accuracy was -11.5-16.3%. Intra-day and inter-day variation are less than 5.9% and 7.3%, respectively. Expanded uncertainty of quantification is less than 0.123ng/g in a solid matrix, less than 0.139ng/ml in a liquid matrix, and less than 0.158ng/g in an oil matrix. Data collected for more than 500 routine samples are presented and discussed.
authors.affiliation: State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China; China Anti-Doping Agency, Beijing 100029, China. Electronic address: zhangjianli@chinada.cn.
authors.forename: Jianli
authors.initials: J
authors.lastname: Zhang
authors.affiliation: China Anti-Doping Agency, Beijing 100029, China.
authors.forename: Yinong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China. Electronic address: wangyan@imm.ac.cn.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
mesh_terms: D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D019587:Dietary Supplements / Q000032:analysis*; D004809:Ephedrine / Q000031:analogs & derivatives* / Q000032:analysis* / Q000302:isolation & purification; D059625:Liquid-Liquid Extraction / Q000379:methods; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods* / Q000592:standards; D053719:Tandem Mass Spectrometry
chemical_list: D004809:Ephedrine
keywords: Dietary supplements; Doping-control; Ephedrine alkaloids; liquid chromatography tandem mass spectrometry (LC-MS/MS)