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Base‐induced transient isotachophoretic stacking of acidic drugs in capillary zone electrophoresis
Author(s) -
Quirino Joselito P.
Publication year - 2011
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201000748
Subject(s) - isotachophoresis , capillary electrophoresis , chemistry , hydroxide , electrolyte , ammonium hydroxide , chromatography , base (topology) , electrophoresis , organic base , capillary action , analyte , potassium hydroxide , stacking , ammonium acetate , ion , analytical chemistry (journal) , inorganic chemistry , electrode , high performance liquid chromatography , organic chemistry , materials science , mathematical analysis , mathematics , composite material
Online sample concentration of acidic drugs by transient isotachophoresis (t‐ITP) with the injection of a base is described in capillary zone electrophoresis (CZE). A positively coated capillary was conditioned with background electrolyte (ammonium acetate at pH 6). A long plug of sample solution (S) prepared in ammonium acetate was then hydrodynamically injected followed by the base (tetrapropylammonium hydroxide). A negative voltage was applied and caused the hydroxide ions from the base to penetrate the S zone and created a pH junction that swept through the S zone. The analytes stack at the junction where the mechanism of focusing was transient ITP with the acetate and hydroxide ions as leading and terminating ions, respectively. The concentrated analytes separated in co‐EOF CZE once the hydroxide was exhausted. The base stacking strategy was tested using hypolipidemic, nonsteroidal anti‐inflammatory, and diuretic drugs, and afforded 19–37 improvements in peak height.