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Transient pseudo‐isotachophoresis for sample concentration in capillary electrophoresis
Author(s) -
Shihabi Zakariya K.
Publication year - 2002
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/1522-2683(200206)23:11<1612::aid-elps1612>3.0.co;2-3
Subject(s) - isotachophoresis , stacking , chromatography , chemistry , capillary action , solvent , capillary electrophoresis , acetone , transient (computer programming) , ion , acetonitrile , analytical chemistry (journal) , electrolyte , materials science , organic chemistry , electrode , composite material , computer science , operating system
We show that many water miscible organic solvents such as acetonitrile, acetone and small alcohols can function as a terminating ion in transient isotachophoresis, which leads to sample concentration on the capillary. It is suggested that this method could be termed transient “pseudo‐isotachophoresis” (pseudo‐ITP). Because of their low conductivity, these water miscible organic solvents provide the high field strength necessary for band sharpening similar to that provided by the terminating ion. Salts, when present in such samples act briefly as leading ions, migrating rapidly in the organic solvent until they are slowed at the interface of the separation buffer. When the organic solvents are added to the sample, both the migrations as well as the stacking of the analytes are affected by the concentration of salts (leading ions) in the sample, similar to that observed in isotachophoresis. Our results show that this type of stacking offers good reproducibility and reliability for practical analysis. In practice, pseudo‐ITP stacking is much easier to perform compared to that of true ITP with several added practical advantages as discussed.