Biosensor based on multi-walled carbon nanotubes paste electrode modified with laccase for pirimicarb pesticide quantification

Abstract

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 substrate 4-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) mol L(-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) mol L(-1) (0.04 mg kg(-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 electroanalysis 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.

Laccase biosensors based on different enzyme immobilization strategies for phenolic compounds determination

“…Recent advances in this field are related to the development of new support matrix as suitable platforms (most of them including nanomaterials) for enzymes immobilization, which lead to biosensors with improved analytical properties. So, in recent works, laccase has been immobilized by direct adsorption, covalent binding or entrapment onto: epoxy resin membranes [9], mesoporous materials with well-controlled pore structures [10,17], multi-walled carbon nanotubes paste electrodes [18], nanocomposites formed by chitosan and carbon nanotubes [19], copper-containing ordered mesoporous carbon chitosan matrix [8], pyrenehexanoic acid-modified hierarchical carbon microfibers/carbon nanotubes composite electrodes [16], polyvinyl alcohol photopolymers [20], sol-gel matrix of 5 diglycerylsilane [21], 3-mercaptopropionic acid self-assembled monolayer modified gold electrodes [22], cysteine self-assembled monolayer and quantum dots modified gold electrodes [23], nanocomposites of silver nanoparticles and zinc oxide nanoparticles electrochemically deposited onto gold electrodes [24], platinum nanoparticles and reduced graphene composites deposited onto screen printed electrodes [25], polyethyleneimine coated gold-nanoparticles modified glassy carbon electrodes…”

Biosensor and Food Industry - Review

“…O biossensor desenvolvido se mostrou uma ferramenta promissora para identificar a presença do pesticida pirimicarbe em amostras de vegetais. 92 Ainda em 2013, LIU et al desenvolveram um biossensor de acetilcolinesterase baseado em um compósito de aerogéis de carbono e platina com o objetivo de determinar pesticidas organofosforados, no caso os metamidofós e monocrotofós. O limite de detecção encontrado foi de 3,1x10 −13 mol.L −1 para metamidofós e 2,7x10 −12 mol.L −1 para monocrotofós.…”

Facilitating electron transfer in bioelectrocatalytic systems

“…For the realisation of substrate recycling, the biosensor reaction should be reversible. Catechols (benzenediols) represent one of the most commonly used substrates in such systems [119][120][121] due to reversibility of the redox reaction of the phenolic ring and due to the relevance of their determination with high sensitivity f or medical, f ood saf ety and environmental applications. In Fig.…”