Name: | Description: | Size: | Format: | |
---|---|---|---|---|
95.84 KB | Adobe PDF |
Advisor(s)
Abstract(s)
A novel enzymatic biosensor for carbamate pesticides detection was developed through the direct
immobilization of Trametes versicolor laccase on graphene doped carbon paste electrode functionalized
with Prussianblue films (LACC/PB/GPE). Graphene was prepared by graphite sonication-assisted
exfoliation and characterized by transmission electron microscopy and X-ray photoelectron spectro-
scopy. The Prussian blue film electrodeposited onto graphene doped carbon paste electrode allowed
considerable reduction of the charge transfer resistance and of the capacitance of the device.The
combined effects of pH, enzyme concentration and incubation time on biosensor response were
optimized using a 23 full-factorial statistical design and response surface methodology. Based on the
inhibition of laccase activity and using 4-aminophenol as redox mediator at pH 5.0,LACC/PB/GPE
exhibited suitable characteristics in terms of sensitivity, intra-and inter-day repeatability (1.8–3.8% RSD),
reproducibility (4.1 and 6.3%RSD),selectivity(13.2% bias at the higher interference: substrate ratios
tested),accuracy and stability(ca. twenty days)for quantification of five carbamates widely applied on
tomato and potato crops.The attained detection limits ranged between 5.2×10−9 mol L−1(0.002 mg kg−1 w/w for ziram)and 1.0×10−7 mol L−1 (0.022 mg kg−1 w/w for carbofuran).Recovery
values for the two tested spiking levels ranged from 90.2±0.1%(carbofuran)to 101.1±0.3% (ziram) for
tomato and from 91.0±0.1%(formetanate)to 100.8±0.1%(ziram)for potato samples.The proposed
methodology is appropriate to enable testing pesticide levels in food samples to fit with regulations and
food inspections.
Description
Keywords
Enzymatic biosensors Graphene Prussian blue films Laccase Carbamates Vegetables
Citation
Publisher
Elsevier