Premium
In‐channel indirect amperometric detection of nonelectroactive anions for electrophoresis on a poly(dimethylsiloxane) microchip
Author(s) -
Xu JingJuan,
Peng Ying,
Bao Ning,
Xia XingHua,
Chen HongYuan
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.200410401
Subject(s) - amperometry , electrophoresis , chromatography , chemistry , channel (broadcasting) , capillary electrophoresis , electrode , computer science , electrochemistry , computer network
In the present paper, we describe a microfluidics‐based sensing system for nonelectroactive anions under negative separation electric field by mounting a single carbon fiber disk working electrode (WE) in the end part of a poly(dimethylsiloxane) microchannel. In contrast to work in a positive separation electric field described in our previous paper ( Anal. Chem. 2004, 76 , 6902—6907), here the electrochemical reduction reaction at the WE is not coupled with the separation high‐voltage (HV) system, whereas the electrochemical oxidation reaction at the WE is coupled with the separation HV system. The electroactive indicator is the carbon fiber WE itself but not dissolved oxygen. This provides a convenient and sensitive means for the determination of nonelectroactive anions by amperometry. The influences of separation voltage, detection potential, and the distance between the WE and the separation channel outlet on the response of the detector have been investigated. The present detection mode is successfully used to electrochemically detect F − , Cl − , SO 4 2‐ , CH 3 COO − , H 2 PO 4‐ . Based on the preliminary results, a detection limit of 2 μ M and a dynamic range up to three orders of magnitude for Cl − could be achieved.