Premium
Electrokinetic supercharging preconcentration prior to CGE analysis of DNA : Sensitivity depends on buffer viscosity and electrode configuration
Author(s) -
Ye Xiaoxue,
Mori Satomi,
Yamada Mihoro,
Inoue Junji,
Xu Zhongqi,
Hirokawa Takeshi
Publication year - 2013
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.201200338
Subject(s) - electrokinetic phenomena , boric acid , chemistry , chromatography , buffer (optical fiber) , analytical chemistry (journal) , electrode , viscosity , capillary electrophoresis , tris , buffer solution , materials science , telecommunications , biochemistry , organic chemistry , computer science , composite material
Aiming to high sensitivity DNA analysis by CGE , electrokinetic supercharging ( EKS ) approach was adopted in this article. EKS is known as an online preconcentration technique that combines electrokinetic sample injection ( EKI ) with transient ITP (t ITP ). Herein, two factors of buffer viscosity and electrode configuration were studied to further improve EKS performance. An ultralow‐viscosity Tris‐Boric acid‐ EDTA ( TBE ) buffer solution, consisted of 2% low‐molecular‐weight hydroxypropyl methyl cellulose ( HPMC ) and 6% mannitol and with p H 8.0 adjusted by boric acid, was applied. The boric acid would make a complex with mannitol and generates borate polyanion, which acts as the leading ion for t ITP process. The new electrode configuration, a P t ring around capillary, was modified on Agilent CE system to lead large amount sample introduction during EKS . The standard DNA sample of φX174/ H aeIII digest was used to evaluate the qualitative and quantitative abilities of the proposed strategy. The 170 000‐fold highly diluted sample at concentration of 3.0 ng/mL was enriched by EKS and detected by normal UV detection method. The obtained LOD of the weakest peak of 72 bp fragment was around 7.7 pg/mL, apparently improved more than 10 000‐fold in comparison with conventional CGE with UV detection.