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Sphere‐Cap Mercury Microelectrodes for Scanning Electrochemical Microscopy Above an Insulating Substrate
Author(s) -
Daniele Salvatore,
Bragato Carlo,
Ciani Ilenia,
Baldo M. Antonietta
Publication year - 2003
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200390078
Subject(s) - scanning electrochemical microscopy , microelectrode , mercury (programming language) , materials science , platinum , analytical chemistry (journal) , diffusion , electrochemistry , substrate (aquarium) , microscopy , radius , electrode , chemistry , optics , chromatography , biochemistry , oceanography , computer security , computer science , thermodynamics , programming language , geology , catalysis , physics
Sphere‐cap mercury microelectrodes, fabricated onto platinum microdisks 1 and 10 μm radius, were employed as tips in scanning electrochemical microscopy (SECM). Experimental current vs distance curves were acquired above an insulating substrate with a series of sphere caps whose aspect ratio h/a ( h is the height of mercury deposit, a is the disk basal radius) varied between 0.28 and 2.14. It was found that the hindered diffusion effect of the insulating surface was the less pronounced the higher was the h/a parameter of the sphere cap. Comparison of experimental and theoretical approach curves displayed a fairly good agreement for subhemisphere caps ( ha ) caps. Preliminary coupled anodic stripping voltammetry and SECM measurements were also performed for the investigation on local chemical equilibria involving heavy metals at sediment/water interfaces.