title: Comparison of field-enhanced and pressure-assisted field-enhanced sample injection techniques for the analysis of water-soluble vitamins using CZE.
abstract: A new online concentration method, namely pressure-assisted field-enhanced sample injection (PA-FESI), was developed and compared with FESI for the analysis of water-soluble vitamins by CZE with UV detection. In PA-FESI, negative voltage and positive pressure were simultaneously applied to initialize PA-FESI. PA-FESI uses the hydrodynamic flow generated by the positive pressure to counterbalance the reverse EOF in the capillary column during electrokinetic sample injection, which allowed a longer injection time than usual FESI mode without compromising the separation efficiency. Using the PA-FESI method, the LODs of the vitamins were at ng/mL level based on the S/N of 3 and the RSDs of migration time and peak area for each vitamin (1 microg/mL) were less than 5.1%. The developed method was applied to the analysis of water-soluble vitamins in corns.
authors.affiliation: Ministry of Education, Key Laboratory of Laser Life Science & Institute of Laser Life Science, South China Normal University, Guangzhou, China.
authors.forename: Qingqing
authors.initials: Q
authors.lastname: Liu
authors.forename: Yaling
authors.initials: Y
authors.lastname: Liu
authors.forename: Yu
authors.initials: Y
authors.lastname: Guan
authors.forename: Li
authors.initials: L
authors.lastname: Jia
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D011312:Pressure; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012995:Solubility; D014815:Vitamins / Q000737:chemistry* / Q000302:isolation & purification*; D014867:Water / Q000737:chemistry*; D003313:Zea mays / Q000737:chemistry
chemical_list: D014815:Vitamins; D014867:Water