Examining ultramicroelectrodes for scanning electrochemical microscopy by white light vertical scanning interferometry and filling recessed tips by electrodeposition of gold.
Anal Chem
; 84(11): 5159-63, 2012 Jun 05.
Article
em En
| MEDLINE
| ID: mdl-22591026
ABSTRACT
In this paper, we present a technique to rapidly and directly examine ultramicroelectrodes (UMEs) by white light vertical scanning interferometry (VSI). This technique is especially useful in obtaining topographic information with nanometer resolution without destruction or modification of the UME and in recognizing tips where the metal is recessed below the insulating sheath. Two gold UMEs, one with a metal radius a = 25 µm and relative insulating sheath radius RG = 2 and the other with a = 5 µm and RG = â¼1.5, were examined, and the average depth of the gold recessions was determined to be 1.15 µm and 910 nm, respectively. Electrodeposition of gold was performed to fill the recessed hole, and the depth was reduced to â¼200 nm. With the electrodeposited gold electrode and a conventional microelectrode (a = 25 µm) as a tip and substrate, respectively, a tip/substrate distance, d, of 600 nm was achieved allowing scanning electrochemical microscopy (SECM) in positive feedback mode at a close distance, which is useful for measuring fast kinetics.
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Base de dados:
MEDLINE
Idioma:
En
Revista:
Anal Chem
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Estados Unidos