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Separation of neutral compounds by capillary electrokinetic chromatography using polyethyleneimine as replaceable cationic pseudostationary phase
Author(s) -
Maichel Beate,
Potocek Blahoslav,
Kenndler Ernst,
Gas Bohuslav,
Chiari Marcella
Publication year - 1998
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/elps.1150191214
Subject(s) - chemistry , electrokinetic phenomena , chromatography , phase (matter) , selectivity , cationic polymerization , capillary action , resolution (logic) , analytical chemistry (journal) , organic chemistry , materials science , artificial intelligence , computer science , composite material , catalysis
Polyethyleneimine (PEI, molecular weight 6 × 10 5 − 1 × 10 6 ) is applied as a positively charged pseudostationary phase for electrokinetic chromatography (EKC) of uncharged mono‐ and oligophenols. EKC is carried out in PEI‐coated fused‐silica capillaries (with electroosmotic flow directed towards the anode) in 2‐( N ‐morpholino)ethanesulfonic acid (MES) buffer (pH 7.0,20 m M ) with PEI added to the solution in concentrations up to 0.70% w/v. The pseudo‐stationary phase leads to a retardation of the solutes mainly according to the number (and the position) of the OH‐groups of the separands, and is not influenced significantly by methyl groups. For 0.70% w/v PEI solution, for instance, the relative retention, ϱ, has values between 0.33 and 0.53. For the systems with the highest resolution of the separands (0.25–0.30% PEI) 190000 plates per meter are observed. The results indicate that the separation selectivity is mainly caused by ion‐dipole interactions between the OH‐groups of the solutes and the pseudostationary phase.