Peer-Reviewed Journal Details
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Ferry, Y,Leech, D
2005
February
Electroanalysis
Amperometric detection of catecholamine neurotransmitters using electrocatalytic substrate recycling at a laccase electrode
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catecholamines redox polymer laccase amperometric detection osmium CHARGE-TRANSFER REACTIONS CARBON-FIBER ELECTRODES ASCORBIC-ACID MICROVOLTAMMETRIC ELECTRODES VOLTAMMETRIC DETERMINATION ELECTROCHEMICAL DETECTION LIQUID-CHROMATOGRAPHY GRAPHITE ELECTRODE ION-EXCHANGE RAT-BRAIN
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An enzyme electrode based on the coirnmobilization of an osmium redox polymer and laccase on glassy carbon electrodes has been applied to ultra sensitive amperometric detection of the catecholamine neurotransmitters dopamine, epinephrine and norepinephrine, resulting in nanomolar detection limits, as low as 4 nM for dopamine. The sensitivity of the electrode is due to signal amplification via oxidation of the catecholamine by the immobilized laccase, which is regenerated by concomitant reduction of oxygen to water, coupled to the electrocatalytic rereduction of the oxidized catecholamine by the osmium redox complex: electrocatalytic substrate recycling. In addition because the sensor can be operated in reductive mode at - 0.2 V (vs. Ag/AgCI), noise and interferences are diminished. Combined with its high sensitivity this enzyme electrode also exhibited excellent selectivity allowing the detection of catecholamines in the presence of ascorbic acid. However, differentiation between the current responses achieved for the three catecholarnines is not possible. The effective mode of constant recycling, resulting in amplification of the current response, of the laccase enzyme electrode sensor combined with the inherent advantages of using electrochemical techniques holds great promise for the future of catecholamine detection and monitoring.
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