Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.22/3344
Título: Biosensor based on multi-walled carbon nanotubes paste electrode modified with laccase for pirimicarb pesticide quantification
Autor: Oliveira, Thiago M. B. F.
Barroso, M. Fátima
Morais, Simone
Lima-Neto, Pedro de
Correia, Adriana N.
Oliveira, M. Beatriz P. P.
Delerue-Matos, Cristina
Palavras-chave: Enzymatic biosensor
Multi-walled carbon nanotubes
Vegetable crops
Data: 2013
Editora: Elsevier
Relatório da Série N.º: Talanta; Vol. 106
Resumo: This study focused on the development of a sensitive enzymatic biosensor for the determination of pirimicarb pesticide based on the immobilization of laccase on composite carbon paste electrodes. Multi- walled carbon nanotubes(MWCNTs)paste electrode modified by dispersion of laccase(3%,w/w) within the optimum composite matrix(60:40%,w/w,MWCNTs and paraffin binder)showed the best performance, with excellent electron transfer kinetic and catalytic effects related to the redox process of the substrate4- aminophenol. No metal or anti-interference membrane was added. Based on the inhibition of laccase activity, pirimicarb can be determined in the range 9.90 ×10- 7 to 1.15 ×10- 5 molL 1 using 4- aminophenol as substrate at the optimum pH of 5.0, with acceptable repeatability and reproducibility (relative standard deviations lower than 5%).The limit of detection obtained was 1.8 × 10-7 molL 1 (0.04 mgkg 1 on a fresh weight vegetable basis).The high activity and catalytic properties of the laccase- based biosensor are retained during ca. one month. The optimized electroanalytical protocol coupled to the QuEChERS methodology were applied to tomato and lettuce samples spiked at three levels; recoveries ranging from 91.0±0.1% to 101.0 ± 0.3% were attained. No significant effects in the pirimicarb electro- analysis were observed by the presence of pro-vitamin A, vitamins B1 and C,and glucose in the vegetable extracts. The proposed biosensor- based pesticide residue methodology fulfills all requisites to be used in implementation of food safety programs.
Peer review: yes
URI: http://hdl.handle.net/10400.22/3344
ISSN: 0039-9140
Versão do Editor: http://www.sciencedirect.com/science/article/pii/S003991401201051X
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