title: On-line sample preconcentration of cationic analytes by dynamic pH junction in capillary electrophoresis.
abstract: To improve detection sensitivity of cationic analytes, a dynamic pH junction technique was examined. Dynamic pH junction is an on-line focusing method in capillary electrophoresis (CE) based on the difference in the analyte's mobility between the background electrolyte (BGE) and sample matrix. The effects of pH values and concentrations of the BGE and the sample matrix on dynamic pH junction were examined. Optimization of analyte focusing resulted in enhanced detection responses of about 100-160-fold in terms of peak heights for some anilines in comparison to conventional injections. In particular, the concentration limits of detection (LOD) (S/N = 3) for the test anilines obtained with dynamic pH junction were from 1.9 to 3.7 ppb with UV detection without any pretreatment procedure.
authors: Graduate School of Science, Himeji Institute of Technology, 3-2-1 Kouto, 1479-1 Kanaji Kamigori, Hyogo 678-1297, Japan. jbkim@sci.himeji-tech.ac.jp
authors: Jong-Bok
authors: JB
authors: Kim
authors: Yusuke
authors: Y
authors: Okamoto
authors: Shigeru
authors: S
authors: Terabe
mesh_terms: D002412:Cations; D019075:Electrophoresis, Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration
chemical_list: D002412:Cations