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Optimization of the electrokinetic supercharging preconcentration for high‐sensitivity microchip gel electrophoresis on a cross‐geometry microchip
Author(s) -
Xu Zhongqi,
Hirokawa Takeshi
Publication year - 2004
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.200305910
Subject(s) - electrokinetic phenomena , chromatography , capillary electrophoresis , sensitivity (control systems) , chemistry , analytical chemistry (journal) , materials science , electrophoresis , nanotechnology , engineering , electronic engineering
We developed a novel on‐line preconcentration procedure for microchip gel electrophoresis (MCGE), which enables application of electrokinetic supercharging (EKS) for highly sensitive detection of DNA fragments on a cross‐geometry microchip. In comparison with conventional pinched injection using the cross microchip, the present approach allows loading a much larger amount of the sample by taking advantage of a newly developed operational mode. In order to obtain high preconcentration effect and prevent splitting of an enriched sample into subchannels, i.e. , off the detector range, effects of the voltage applied on the reservoirs and the time of isotachophoretic preconcentration were examined. The optimal balance between the voltage and time was found for a high‐sensitivity analysis of DNA fragments. After experimental optimization the detection limit of a 150 bp fragment was as low as 0.22 mg/L (S/N = 3) that is 10 times better than using the conventional pinched injection.