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Low‐temperature bath/coupled‐capillary/sweeping‐micellar electrokinetic capillary chromatography for the separation of naphthalene‐2,3‐dicarboxaldehyde‐derivatized dopamine and norepinephrine
Author(s) -
Shih ChunMin,
Lin ChengHuang
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.200510409
Subject(s) - micellar electrokinetic chromatography , capillary action , chemistry , chromatography , analyte , capillary electrochromatography , capillary electrophoresis , electrokinetic phenomena , micelle , analytical chemistry (journal) , aqueous solution , materials science , organic chemistry , composite material
The use of a low‐temperature (0°C) bath‐assisted coupled capillary for the separation of naphthalene‐2,3‐dicarboxaldehyde (NDA)‐derivatized dopamine and norepinephrine using the sweeping‐micellar electrokinetic capillary chromatography (MEKC) mode is described. In this technique, a capillary consisting of two portions with different inside diameters is used. Therefore, the field strength inside the capillary is different. Hence, the electrophoretic migration velocities of the analytes and the electroosmotic flow (EOF) also are different. Furthermore, when a portion of the capillary (wide portion, used for sweeping) is immersed in a low‐temperature bath, the viscosity of the buffer and the retention factor of the analytes inside are increased. Thus, not only are the interactions between the SDS micelles and the analytes increased, but the SDS‐analytes also move more slowly. As a result, a more complete separation can be achieved, even when the sample injection volume is large, up to ∼ 2 μL. In general, when the volume of an injected sample is larger, the effects of sweeping and separation would become insufficient, especially when the retention values ( k ) of the analytes are quite different. However, this limitation can be improved when the low‐temperature bath/coupled capillary/sweeping‐MEKC mode is used.