title: [Determination of main free amino acids in Banlangen Keli by UPLC].
abstract: OBJECTIVE
  To establish a quantitative method with precolumn derivatization for determining the contents of six common amino acids in Banlangen Keli by UPLC.
  
  
  METHODS
  Using 6-acetamido-4-hydroxy-2-methyl quinoline as the derivating agent, we determined the contents of arginine, threonine , alanine, gamma aminobutyric acid, proline, and valine. The UPLC analysis was performed on a Waters AccQ Tag TM Ultra C18 column (2.1 mm x 100 mm, 5 microm) with mobile phase AccQ Tag Ultra Eluent A and AccQ Tag Ultra Eluent B gradient elution at a flow rate of 0.7 mL x min(-1). The column temperature was 55 degrees C and detection wavelength was 260 nm.
  
  
  RESULTS
  The linear ranges of arginine, thremine, alanine, gamma aminobutyric acid, proline, and valine were 4. 15549.86 microg (r = 0.999 9), 0.595-5.95 microg (r = 0.999 8), 0.445-4.45 microg (r = 0. 999 9), 0.515-5. 15 pg (r = 0.999 9), 8.858-106.3 microg (r = 0.999 9) , 0.585-5. 85 microg (r = 0.999 8). Their average recoveries were 100.6%, 98.35%, 100.2%, 98.44%, 98.34%, 98.18% with RSD 1.8%,1.9%, 2.0%, 2.4%, 1.5% and 2.0%, respectively (n = 6). The contents of amino acids were different in samples from five productive enterprises.
  
  
  CONCLUSIONS
  The method is efficient, good reproducible, sensitive, and accurate.
authors.affiliation: Beijing Insititute for Drug Control, Beijing 100035, China.
authors.forename: Mintong
authors.initials: M
authors.lastname: Xin
authors.forename: Xintong
authors.initials: X
authors.lastname: Fu
authors.forename: Yougen
authors.initials: Y
authors.lastname: Chen
authors.forename: Hongzhu
authors.initials: H
authors.lastname: Guo
mesh_terms: D000596:Amino Acids / Q000032:analysis*; D002853:Chromatography, Liquid; D004365:Drugs, Chinese Herbal / Q000737:chemistry*; D015203:Reproducibility of Results
chemical_list: D000596:Amino Acids; D004365:Drugs, Chinese Herbal; C540579:banlangen