On-line sequential preconcentration of inorganic anions by anion-selective exhaustive injection and base-stacking in capillary zone electrophoresis.
A sequential electrostacking method based on anion-selective exhaustive injection (ASEI) and base-stacking (BS) is presented for the preconcentration and determination of inorganic anions by capillary zone electrophoresis (CZE) in this paper. Tetradecyltrimethylammonium bromide as an electroosmotic flow (EOF) modifier was added into the buffer to suppress EOF of the capillary. Firstly, a water plug was hydrodynamically injected into the capillary. During ASEI under negative high voltage, the sample anions migrated quickly towards the boundary between the water plug and buffer in the capillary. Then an alkaline zone was injected electrokinetically to concentrate the anions further. With the sequential electrostacking method, the preconcentration factor of (0.8-1.3) x 10(5) was obtained compared with the conventionally electrokinetic injection and the relative standard deviation of peak area was 3.3-5.3% (n = 5). The detection limits of ASEI-BS-CZE for six inorganic anions were 6-14 ng/L. The proposed method has been adopted to analyze six anions in cigarette samples successfully.
Zhang
Zhao-Xiang
ZX
Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
He
You-Zhao
YZ
Hu
Yan-Yun
YY
D000838:Anions / Q000032:analysis*; D019075:Electrophoresis, Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D007287:Inorganic Chemicals / Q000032:analysis*; D000644:Quaternary Ammonium Compounds; D014026:Nicotiana; D050337:Trimethyl Ammonium Compounds
D000838:Anions; D007287:Inorganic Chemicals; D000644:Quaternary Ammonium Compounds; D050337:Trimethyl Ammonium Compounds; C009410:tetradecyltrimethylammonium