On-line focusing of 5-hydroxy-tryptamine type 3 receptor antagonists via the combination of field-enhanced sample injection and dynamic pH junction in capillary electrophoresis with amperometric detection.
In the present work, an on-line dual focusing technique based on field-enhance sample injection (FASI) and dynamic pH junction (DypH) was developed for the analysis of two 5-hydroxy-tryptamine type 3 receptor (5-HT3) antagonists ondansetron (Ond) and tropisetron (Tro) by capillary electrophoresis with amperometric detection (CE-AD) system. By preparing the sample in a lower conductivity (FASI condition) and lower pH value (DypH condition) matrix relative to the background electrolyte (BGE) solution, a simple and effective dual focusing approach, FASI-DypH was achieved. In this stacking mode, a large amount of analytes could be electrokinetically injected into the capillary and stacked at the boundary of the sample and the BGE zone as a result of deprotonation and decrease in the electric field. Effects of separation, detection and FASI-DypH focusing conditions were investigated in detail. Under the optimum conditions, good separation for Ond and Tro was achieved within 8min. In comparison with the conventional CE-AD analysis method, the present dual focusing technique enabled the enhancement factors in terms of peak heights to reach 357-fold and 345-fold for Ond and Tro, respectively. The limits of detection (LODs) (S/N=3) for Ond and Tro were 2nM and 5nM, respectively. The intraday and interday repeatabilities (RSDs) were less than 4.5% and 2.9% for peak height and migration time, respectively. The proposed method was successfully applied for the analysis of Ond and Tro in human urine sample.
State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China.
Libo
L
Li
State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China.
Lei
L
Xu
State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China.
Jianshe
J
Huang
State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China. Electronic address: youty@ciac.jl.cn.
Tianyan
T
You
D000932:Antiemetics / Q000032:analysis* / Q000652:urine; D019075:Electrophoresis, Capillary / Q000379:methods; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007211:Indoles / Q000032:analysis* / Q000652:urine; D057230:Limit of Detection; D017294:Ondansetron / Q000032:analysis* / Q000652:urine; D058831:Serotonin 5-HT3 Receptor Antagonists / Q000032:analysis* / Q000652:urine; D000077526:Tropisetron
D000932:Antiemetics; D007211:Indoles; D058831:Serotonin 5-HT3 Receptor Antagonists; D017294:Ondansetron; D000077526:Tropisetron
5-HT(3) receptor antagonists; Amperometric detection; Capillary electrophoresis; Dynamic pH junction; Field-enhanced sample injection