Please use this identifier to cite or link to this item: http://hdl.handle.net/10316/7772
Title: Glucose oxidase inhibition in poly(neutral red) mediated enzyme biosensors for heavy metal determination
Authors: Ghica, Mariana 
Brett, Christopher 
Issue Date: 2008
Abstract: Abstract A biosensor for the determination of heavy metal cations based on glucose oxidase enzymatic inhibition has been developed. The biosensor was assembled on carbon film electrode supports with glucose oxidase immobilised by cross-linking with glutaraldehyde on top of a film of poly(neutral red) as redox mediator, prepared by electropolymerisation. The biosensor was used to determine the metallic cations, cadmium, copper, lead and zinc in the presence of chosen amounts of glucose. The detection limits were found to be 1 µg L-1 for cadmium, 6 µg L-1 for copper, 3 µg L-1 for lead and 9 µg L-1 for zinc. Inhibition constants were determined by using the Dixon plot, and the type of inhibition induced by the metallic cations was evaluated from Cornish-Bowden plots plus Dixon plots, it being found that the inhibition is reversible and competitive for cadmium, mixed for copper and lead and uncompetitive for zinc. Copper-inhibited glucose oxidase to a greater extent followed by cadmium, lead and zinc. Regeneration of the glucose oxidase response was studied by using Ethylene diamine tetracetic acid metal-chelating agent and the nonionic surfactant Triton X-100. The suitability of the biosensor for determination in foodstuffs or beverages which contain trace concentrations of metals was investigated by performing recovery tests in commercial milk samples.
URI: http://hdl.handle.net/10316/7772
DOI: 10.1007/s00604-008-0018-1
Rights: openAccess
Appears in Collections:FCTUC Química - Artigos em Revistas Internacionais

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