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Dual‐asymmetry electrokinetic flow focusing for pre‐concentration and analysis of catecholamines in CE electrochemical nanochannels
Author(s) -
Wu RenGuei,
Yang ChungShi,
Lian ChengKuang,
Cheing ChingChang,
Tseng FanGang
Publication year - 2009
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.200800809
Subject(s) - electrokinetic phenomena , zeta potential , detection limit , electrode , analytical chemistry (journal) , electrochemistry , chemistry , materials science , chromatography , nanotechnology , nanoparticle
In this research, a technique incorporating dual‐asymmetry electrokinetic flow (DAEKF) was applied to a nanoCE electrochemical device for the pre‐concentration and detection of catecholamines. The DAEKF was constructed by first generating a ζ‐potential difference between the top and bottom walls, which had been pre‐treated with O 2 and H 2 O surface plasma, respectively, yielding a 2‐D gradient shear flow across the channel depth. The shear flow was then exposed to a varying ζ‐potential along the downstream direction by control of the field‐effect in order to cause downward rotational flow in the channel. By this mechanism, almost all of the samples were effectively brought down to the electrode surface for analysis. Simulations were carried out to reveal the mechanism of concentration caused by the DAEKF, and the results reasonably describe our experiment findings. This DAEKF technique was applied to a glass/glass CE electrochemical nanochip for the analysis of catecholamines. The optimum detection limit was determined to be 1.25 and 3.3 nM of dopamine and catechol, respectively. A detection limit at the zeptomole level for dopamine can be obtained in this device, which is close to the level released by a single neuron cell in vitro .