title: Online preconcentration and two-dimensional separation of cationic compounds via hyphenation of capillary zone electrophoresis with cyclodextrin-modified micellar electrokinetic capillary chromatography.
abstract: A novel preconcentration/separation approach, which online combined CZE with CD-modified MEKC, was developed for simultaneous enhancing resolving power and detection sensitivity. CZE with cation-selective exhaustive injection and transient ITP preconcentration was used as the first dimension, from which the effluent fractions were further analyzed by CD-modified MEKC acting as the second dimension. As the key to successful integration of CZE with MEKC, a new interface was designed and electroaccumulation focusing strategy was employed to avoid analyte band diffusion at the interface. The comprehensive 2-D system was successfully established with only one high voltage and four electrodes. The grouping of two orthogonal separation techniques, together with analytes preconcentration techniques, significantly enhanced resolution and sensitivity for 2-D separation of cationic compounds. The resulting electrophoregram was quite different from that of either single CZE or MEKC. Up to 14,000- to 35,000-fold improvement in sensitivity was obtained relative to conventional electrokinetic injection method. The limits of detection (S/N=3) were in the range of 0.03-0.1 microg/L. The number of theoretical plates was in the range of 103,000-184,000. This method was successfully applied to the analysis of trace cationic cardiovascular drugs in wastewater.
authors.affiliation: Key Laboratory of Eco-chemical Engineering, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, P. R. China.
authors.forename: Zhao-Xiang
authors.initials: ZX
authors.lastname: Zhang
authors.forename: Ming-Zhe
authors.initials: MZ
authors.lastname: Zhang
authors.forename: Shu-Sheng
authors.initials: SS
authors.lastname: Zhang
mesh_terms: D002317:Cardiovascular Agents / Q000302:isolation & purification; D002412:Cations / Q000302:isolation & purification; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D003505:Cyclodextrins / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000379:methods*; D004867:Equipment Design; D012680:Sensitivity and Specificity; D012972:Sodium Hydroxide / Q000737:chemistry; D018511:Systems Integration; D014874:Water Pollutants, Chemical / Q000302:isolation & purification
chemical_list: D002317:Cardiovascular Agents; D002412:Cations; D003505:Cyclodextrins; D014874:Water Pollutants, Chemical; D012972:Sodium Hydroxide