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Large‐volume stacking in capillary electrophoresis using pH hysteresis of the electroosmotic flow in a bare fused‐silica capillary
Author(s) -
Han Ji Hye,
Chun ManSeog,
Riaz Asif,
Chung Doo Soo
Publication year - 2005
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.200410274
Subject(s) - capillary electrophoresis , capillary action , stacking , flow (mathematics) , volume (thermodynamics) , electro osmosis , hysteresis , chromatography , chemistry , materials science , analytical chemistry (journal) , electrophoresis , mechanics , thermodynamics , physics , composite material , organic chemistry , quantum mechanics
For large‐volume stacking with the electroosmotic flow pump (LVSEP) in capillary electrophoresis of anionic analytes it is required that the electroosmotic mobility (EOM) should be smaller than the magnitudes of the effective mobilities of the analytes. When a fused‐silica capillary is treated with an acidic solution, the silanoate group on the silica surface is neutralized to silanol and the EOM is suppressed. Due to the slow deprotonation equilibrium of the silanol group at an intermediate pH, this reduced EOM can be retained during a number of electrophoresis runs. Using a bare fused‐silica capillary preconditioned with 0.01 M HCl, successful LVSEP at pH 6.0 was achieved for weakly acidic compounds with two orders of magnitude enhancements in the concentration sensitivity. The repeatability in migration times of ten analytes stacked by LVSEP in a single day was excellent with the relative standard deviation (RSD) less than 1% ( n = 6). The day‐to‐day repeatability was also excellent with RSD less than 3% ( n = 3×6) when the capillary was preconditioned each day.