Graphenated polyanilino-horse radish peroxidate nanobiosensor for the determination of carbamate pesticides in fruits
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Date
2014
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University of the Western Cape
Abstract
In this study, simple, sensitive and low cost electrochemical biosensors for quantitative determination of the carbamate pesticides in real fruit samples have been constructed. Firstly, poly (2.5-dimethoxyaniline) (PDMA) and GO-PANl composite were synthesised on platinum electrode by the electrochemical method using polyvinylsulphonate (PVS) as the dopant for POMA. Fourier transform infrared (FTIR) spectroscopy and UV-Vis spectroscopy studies concluded successful doping of the POMA polymer film by PVS. The biosensor was then constructed by electrostatic attachment of the enzyme, horseradish peroxidase (HRP) onto the surface of the platinum and PDMA-PVS modified electrode. Voltammetric results concluded that HRP immobilised on the Pt/GO-PANI composite and Pt/PDMA-PVS film retained its bioelectrocatalytic activity towards the reduction of H2O2 and was not changed during its immobilisation. The Pt/GO-PANI/HRP and Pt/PDMA-PVS/HRP biosensors were then applied to successfully detect standard carbamate pesticides in a 0.1 M phosphate buffer, 0.1 M PB (pH = 6.8 & 7.2) solution. Various performance and stability parameters were evaluated for the Pt/GO-PANI/HRP and Pt/PDMA-PVS/HRP biosensors. These factors include the optimal enzyme loading, effect of pH and long-term stability of the biosensor on the amperometric behaviour of the biosensor (Songa et al., 2008 and Somerset et al., 2007). The Pt/GO-PANI/HRP and Pt/PDMA-PVS/HRP biosensors were finally applied for the detection of three different carbamates pesticides like carbaryl, carbofuran and methomyl in fruit samples. The biosensing principle was based on determination of the sensor response to the carbamates by amperometric and voltammetric methods.
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Keywords
Conducting polymer, Organic phase biosensor, Carbamate pesticides, Fruit samples, Polyanilino-horse