Zm. Liu et al., Carbon film-based interdigitated array microelectrode used in capillary electrophoresis with electrochemical detection, ANALYT CHEM, 72(6), 2000, pp. 1315-1321
A carbon film based interdigitated ring-shaped array (IDRA) microelectrode
was applied to capillary electrophoresis with electrochemical detection to
enhance the detection sensitivity on the basis of the redox cycling of elec
trochemical reversible species at the IDRA microelectrode. We propose a sim
ple capillary-electrode connection device that consists of an X-Y-Z fiber a
ligner, an electrochemical cell, and a Nafion tubing joint that will enable
the detection capillary to be aligned easily on the IDRA microelectrode an
d isolate the separation voltage from the electrochemical detection system.
We used the off-column amperometric detection of aqueous ferrocene and cat
echolamines by capillary electrophoresis with an IDRA microelectrode to inv
estigate the effects of the capillary-to-electrode distance and the separat
ion voltage on the response currents in single and dual modes and the colle
ction efficiencies (CE) and redox cycles (Rc) at the IDRA microelectrode. T
he results show that CE and Rc increase when we increase the distance and l
ower the separation voltage. The limiting currents also increase as the sep
aration voltage decreases in the dual mode. Under optimum conditions, the C
E and Rc of catechol, with good reversibility, reach 83.9% and 3.67, respec
tively. Our results showed that dual-mode detection with the IDRA microelec
trode was capable of achieving lower detection limits than single-mode dete
ction.