title: Online concentration by field-amplified sample injection in acidic buffer for analysis of fangchinoline and tetrandrine in herbal medicine by flow injection-micellar electrokinetic capillary chromatography.
abstract: A novel, rapid, and continuous online concentration approach based on field-amplified sample injection for the analysis of fangchinoline and tetrandrine was developed in this paper by combination of flow injection-MEKC. The BGE used was a solution composed of 75 mM H3PO4-triethylamine-2.5% v/v polyoxyethylene sorbitan monolaurate-20% v/v methanol buffer (pH* 5.0). The analytes prepared in 50% v/v aqueous ethanol were used as the test analytes. Sample was injected electrokinetically between plugs of water. When the cations reached the boundary between the water plug and BGE, they slowed down and became concentrated. Thereafter, MEKC was initiated for the separation. This results in 6.8-8.9-fold improvement in concentration sensitivity relative to conventional CE methods. The separation could be achieved within 10 min and sample throughput rate can reach up to 50/h. The repeatability (defined as RSD) was 4.8, 4.4% with peak height evaluation and 3.6, 0.94% with peak area evaluation for TET and FAN, respectively.
authors.affiliation: Department of Chemistry, Lanzhou University, Lanzhou, PR China.
authors.forename: Lihong
authors.initials: L
authors.lastname: Liu
authors.forename: Xingguo
authors.initials: X
authors.lastname: Chen
authors.forename: Zhide
authors.initials: Z
authors.lastname: Hu
mesh_terms: D000470:Alkaloids / Q000032:analysis*; D044182:Benzylisoquinolines / Q000032:analysis*; D002021:Buffers; D020374:Chromatography, Micellar Electrokinetic Capillary; D017022:Flow Injection Analysis; D044367:Phase Transition; D012680:Sensitivity and Specificity
chemical_list: D000470:Alkaloids; D044182:Benzylisoquinolines; D002021:Buffers; C009438:tetrandrine; C060802:fangchinoline