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ITP in dynamically double‐coated fused‐silica capillaries
Author(s) -
Caslavska Jitka,
Thormann Wolfgang
Publication year - 2006
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.200600346
Subject(s) - ionic strength , electrokinetic phenomena , absorbance , chemistry , electrophoresis , analytical chemistry (journal) , ionic bonding , detector , chromatography , ion , optics , physics , organic chemistry , aqueous solution
Abstract Bidirectional ITP in fused‐silica capillaries double‐coated with Polybrene and poly‐(vinylsulfonate) is a robust approach for analysis of low‐molecular‐mass compounds. EOF towards the cathode is strong (mobility >4.0×10 −8 m 2 /Vs) within the entire pH range investigated (2.40–8.08), dependent on ionic strength and buffer used and, at constant ionic strength, higher at alkaline pH. Electrokinetic separations and transport in such coated capillaries can be described with a dynamic computer model which permits the combined simulation of electrophoresis and electroosmosis in which the EOF is predicted either with a constant ( i.e. pH‐ and ionic strength‐independent) or a pH‐ and ionic strength‐dependent electroosmotic mobility. Detector profiles predicted by computer simulation agree qualitatively well with bidirectional isotachopherograms that are monitored with a setup comprising two axial contactless conductivity detectors and a UV absorbance detector. The varying EOF predicted with a pH‐ and ionic strength‐dependent electroosmotic mobility can be regarded as being realistic.