title: The in-capillary DPPH-capillary electrophoresis-the diode array detector combined with reversed-electrode polarity stacking mode for screening and quantifying major antioxidants in Cuscuta chinensis Lam.
abstract: An in-capillary 2, 2-diphenyl-1-picrylhydrazyl (DPPH)-CE-the DAD (in-capillary DPPH-CE-DAD) combined with reversed-electrode polarity stacking mode has been developed to screen and quantify the active antioxidant components of Cuscuta chinensis Lam. The operation parameters were optimized with regard to the pH and concentration of buffer solution, SDS, β-CDs, organic modifier, as well as separation voltage and temperature. Six antioxidants including chlorogenic acid, p-coumaric acid, rutin, hyperin, isoquercitrin, and astragalin were screened and the total antioxidant activity of the complex matrix was successfully evaluated based on the decreased peak area of DPPH by the established DPPH-CE-DAD method. Sensitivity was enhanced under reversed-electrode polarity stacking mode and 10- to 31-fold of magnitude improvement in detection sensitivity for each analyte was attained. The results demonstrated that the newly established in-capillary DPPH-CE-DAD method combined with reversed-electrode polarity stacking mode could integrate sample concentration, the oxidizing reaction, separation, and detection into one capillary to fully automate the system. It was considered a suitable technique for the separation, screening, and determination of trace antioxidants in natural products.
authors.affiliation: Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, P. R. China.|Tianjin Key Laboratory of Phytochemistry and Pharmaceutical Analysis, Tianjin University of Traditional Chinese Medicine, Tianjin P. R., China.
authors.forename: Jiao
authors.initials: J
authors.lastname: Liu
authors.affiliation: Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, P. R. China.|Tianjin Key Laboratory of Phytochemistry and Pharmaceutical Analysis, Tianjin University of Traditional Chinese Medicine, Tianjin P. R., China.
authors.forename: Ji
authors.initials: J
authors.lastname: Tian
authors.affiliation: Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, P. R. China.|Tianjin Key Laboratory of Phytochemistry and Pharmaceutical Analysis, Tianjin University of Traditional Chinese Medicine, Tianjin P. R., China.
authors.forename: Jin
authors.initials: J
authors.lastname: Li
authors.affiliation: Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, P. R. China.|Tianjin Key Laboratory of Phytochemistry and Pharmaceutical Analysis, Tianjin University of Traditional Chinese Medicine, Tianjin P. R., China.
authors.forename: John Teye
authors.initials: JT
authors.lastname: Azietaku
authors.affiliation: Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, P. R. China.|Tianjin Key Laboratory of Phytochemistry and Pharmaceutical Analysis, Tianjin University of Traditional Chinese Medicine, Tianjin P. R., China.
authors.forename: Bo-Li
authors.initials: BL
authors.lastname: Zhang
authors.affiliation: Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, P. R. China.|Tianjin Key Laboratory of Phytochemistry and Pharmaceutical Analysis, Tianjin University of Traditional Chinese Medicine, Tianjin P. R., China.
authors.forename: Xiu-Mei
authors.initials: XM
authors.lastname: Gao
authors.affiliation: Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, P. R. China.|Tianjin Key Laboratory of Phytochemistry and Pharmaceutical Analysis, Tianjin University of Traditional Chinese Medicine, Tianjin P. R., China.
authors.forename: Yan-Xu
authors.initials: YX
authors.lastname: Chang
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D001713:Biphenyl Compounds; D002021:Buffers; D034182:Cuscuta / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D006863:Hydrogen-Ion Concentration; D010851:Picrates; D012680:Sensitivity and Specificity
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D002021:Buffers; D010851:Picrates; C004931:1,1-diphenyl-2-picrylhydrazyl
keywords: Antioxidant; Cuscuta chinensis Lam; In-capillary DPPH-CE; Reversed-electrode polarity stacking