Overoxidized Polypyrrole-Coated Carbon Fiber Microelectrodes for Dopamine Measurements with Fast-Scan Cyclic Voltammetry

Thin films of overoxidized polypyrrole have been electrochemically coated onto carbon fiber microelectrodes and used for dopamine measurements with background-subtracted, fast-scan cyclic voltammetry at a scan rate of 300 V/s. The films were stable on the electrode surface only when the electrodes w...

Full description

Saved in:
Bibliographic Details
Published in:Analytical chemistry (Washington) 1996-07, Vol.68 (13), p.2084-2089
Main Authors: Pihel, Karin, Walker, Q. David, Wightman, R. Mark
Format: Article
Language:English
Subjects:
Analysis
Animals
Biological and medical sciences
Brain Chemistry
Carbon
Chemistry
Dopamine - analysis
Electrochemistry
General pharmacology
Instruments
Male
Measurement
Medical sciences
Microelectrodes
Oxidation-Reduction
Pharmacology. Drug treatments
Rats
Rats, Sprague-Dawley
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Thin films of overoxidized polypyrrole have been electrochemically coated onto carbon fiber microelectrodes and used for dopamine measurements with background-subtracted, fast-scan cyclic voltammetry at a scan rate of 300 V/s. The films were stable on the electrode surface only when the electrodes were scanned to high potentials (1400 mV vs SSCE) in pH 7.4 aqueous buffer. Dopamine sensitivity and ascorbate and dihydroxyphenylacetic acid (DOPAC) rejection at the overoxidized polypyrrole-coated electrode were compared to those at carbon fiber electrodes coated with Nafion, a perfluorinated ion-exchange material. At 300 V/s, the overoxidized polypyrrole-coated electrode was almost 3 times more sensitive to dopamine than an uncoated disk electrode. Furthermore, the films were as effective as Nafion in the attenuation of the response to ascorbate and DOPAC, common interferences of dopamine in vivo. Overoxidized polypyrrole-coated electrodes maintained a stable response to dopamine for several hours when implanted in the rat brain. The electrochemical deposition procedure was effective at both elliptical and cylindrical electrodes. This is in contrast to the dip-coating procedures employed with Nafion films that lead to nonuniform coatings at cylindrical electrodes.
ISSN:0003-2700
1520-6882
DOI:10.1021/ac960153y