title: [Separation and determination of ephedrine alkaloids and 2,3,5,6-tetramethyl pyrazine in Ephedra herba by HPLC].
abstract: A sensitive and reliable high performance liquid chromatographic method(HPLC) has been developed for the first time for the simultaneous determination of the active ingredients of ephedrine alkaloids and 2,3,5,6-tetramethyl pyrazine (TMP) in Ephedra herba crude drug and two Chinese traditional medicines (Xiao-er qingfeiwan and Lu-si kewan). The HPLC assay was performed on a reversed phase C18 column (Nova-Pak C18, 3.9 mm i.d. x 150 mm) by using methanol-0.02 mol/L KH2PO4-acetic acid-triethyl amine (4:96:0.2:0.01, V/V) as mobile phase for the ephedrine alkaloids analysis and methanol-H2O-acetic acid (35:65:0.5, V/V) as mobile phase for TMP analysis. Regression equations revealed the linear relationships (correlation coefficients: 0.991-0.998) between the peak area of each constituent (E, PE, NE, NPE, TMP) and its concentration. The detection limits for E, PE, NE, NPE and TMP were 0.4 mg/L, 0.1 mg/L, 0.03 mg/L, 0.02 mg/L and 0.03 mg/L, respectively, and the recoveries ranged between 92%-103%. The contents of E, PE, NE, NPE, TMP in Ephedra herba, traditional medicine Xiao-er qingfeiwan and Lu-si kewan were determined respectively. The relative standard deviations (RSD) of the contents ranged between 1.1%-3%.
authors.affiliation: Department of Chemistry, Tsinghua University, Beijing 100084, China.
authors.forename: H X
authors.initials: HX
authors.lastname: Li
authors.forename: M Y
authors.initials: MY
authors.lastname: Ding
authors.forename: K
authors.initials: K
authors.lastname: Lü
authors.forename: J Y
authors.initials: JY
authors.lastname: Yu
mesh_terms: D000470:Alkaloids / Q000032:analysis / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid; D029790:Ephedra sinica / Q000737:chemistry*; D004809:Ephedrine / Q000032:analysis* / Q000302:isolation & purification; D010665:Phenylpropanolamine / Q000032:analysis* / Q000302:isolation & purification; D011719:Pyrazines / Q000032:analysis* / Q000302:isolation & purification
chemical_list: D000470:Alkaloids; D011719:Pyrazines; D010665:Phenylpropanolamine; D004809:Ephedrine; C017953:tetramethylpyrazine