A strategy for selective detection based on interferent depleting and redox cycling using the plane-recessed microdisk array electrodes

Abstract

The fabrication, characterization and application of the plane-recessed microdisk array electrodes for selective detection are demonstrated. The electrodes, fabricated by lithographic microfabrication technology, are composed of a planar film electrode and a 32 x 32 recessed microdisk array electrode. Different from commonly used redox cycling operating mode for array configurations such as interdigitated array electrodes, a novel strategy based on a combination of interferent depleting and redox cycling is proposed for the electrodes with an appropriate configuration. The planar film electrode (the plane electrode) is used to deplete the interferent in the diffusion layer. The recessed microdisk array electrode (the microdisk array), locating within the diffusion layer of the plane electrode, works for detecting the target analyte in the interferent-depleted diffusion layer. In addition, the microdisk array overcomes the disadvantage of low current signal for a single microelectrode. Moreover, the current signal of the target analyte that undergoes reversible electron transfer can be enhanced due to the redox cycling between the plane electrode and the microdisk array. Based on the above working principle, the plane-recessed microdisk array electrodes break up the restriction of selectively detecting a species that exhibits reversible reaction in a mixture with one that exhibits an irreversible reaction, which is a limitation of single redox cycling operating mode. The advantages of the plane-recessed microdisk array electrodes are verified by detecting dopamine in the presence of ascorbic acid and detecting pyrocatechol in the presence of hydroquinone, i.e., the electrodes can work regardless of the reversibility of interfering species. (C) 2011 Elsevier Ltd. All rights reserved.Natural Science Foundation of China (NSFC)[20973144, 21033007, 21021002]; Special Funds for Major State Basic Research Project of China[2007CB935603