Integration of separation capillary with a Au film electrode and an etched decoupler in amperometric capillary electrophoresis

Introduced in this article is fabrication of an integrated capillary for the applications of electrochemical detection in capillary electrophoresis. The separation section, voltage decoupler, and working electrode were composed into a single section of capillary. The porous decoupler was constructed by HF etching till the thickness of the capillary wall less than 20 mu m. The working electrode was prepared by sputtering Au-films on the outlet of the capillary. The integration of the separation capillary with a complete detection assembly improves the convenience for the routine application of electrochemical measurements in capillary electrophoresis. For a 100-mu m-i.d. capillary, the theoretical plate number of catechol and the migration time reproducibility can reach 120,000 and 1.9 % RSD, respectively. The linear range exceeds 3 order of magnitude and the detection limit is lower than 0.65 mu M.