title: [Research on determination of chemical purity of andrographolide by coulometric titration method].
abstract: The determination of chemical purity of andrographolide by coulometric titration method is studied in this paper. The coulometric titration was carried out in a mixture composed of 4 mol x L(-1) hydrochloric acid and 1 mol x L(-1) potassium bromide solution and 1 mol x L(-1) potassium nitrate solution (1:1). Bromine is electrogenerated at the anode and reacts with the andrographolide. The number of electrons involved in the eleatrode reaction is 2. Purity of andrographolide is 99.76% compared with 99.77% utilizing area normalization method by HPLC. The RSD are 0.33% and 0.02% respectively. The results from two methods are consistent, so the determination of chemical purity of andrographolide by coulometric titration method is scientific and feasible. The method is rapid, simple, convenient, sensitive and accurate. The reference material is not essential in the method. The method is suitable for determination of chemical purity of andrographolide.
authors.affiliation: Institute of Materia Medica, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing 100050, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Yang
authors.forename: Dezhi
authors.initials: D
authors.lastname: Yang
authors.forename: Lishen
authors.initials: L
authors.lastname: Xu
authors.forename: Yang
authors.initials: Y
authors.lastname: Lv
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004224:Diterpenes / Q000032:analysis* / Q000302:isolation & purification; D004572:Electrolysis; D004573:Electrolytes / Q000737:chemistry; D007202:Indicators and Reagents / Q000737:chemistry; D016014:Linear Models; D015203:Reproducibility of Results
chemical_list: D004224:Diterpenes; D004573:Electrolytes; D007202:Indicators and Reagents; C030419:andrographolide