Detection of trace levels of organophosphate pesticides using an electronic tongue based on graphene hybrid nanocomposites

Author(s)

Facure, Murilo H. M. ; Mercante, Luiza A. ; Mattoso, Luiz H. C. ; Correa, Daniel S.

• Document type: Journal article
• Source: Talanta; v. 167, p. 59-66, MAY 15 2017.
• Web of Science Citations: 41

Abstract

Organophosphate (OP) compounds impose significant strains on public health, environmental/food safety and homeland security, once they have been widely used as pesticides and insecticides and also display potential to be employed as chemical warfare agents by terrorists. In this context, the development of sensitive and reliable chemical sensors that would allow in-situ measurements of such contaminants is highly pursued. Here we report on a free-enzyme impedimetric electronic tongue (e-tongue) used in the analysis of organophosphate pesticides comprising four sensing units based on graphene hybrid nanocomposites. The nanocomposites were prepared by reduction of graphene oxide in the presence of conducting polymers (PEDOT:PSS and polypyrrole) and gold nanoparticles (AuNPs), which were deposited by drop casting onto gold interdigitated electrodes. Impedance spectroscopy measurements were collected in triplicate for each sample analyzed, and the electrical resistance data were treated by Principal Component Analysis (PCA), revealing that the system was able to discriminate OPs at nanomolar concentrations. In addition, the electronic tongue system could detect OPs in real samples, where relations between the principal components and the variation of pesticides in a mixture were established, proving to be useful to analyze and monitor mixtures of OP pesticides. The materials employed provided sensing units with high specific surface area and high conductivity, yielding the development of a sensor with suitable stability, good reproducibility, and high sensitivity towards pesticide samples, being able to discriminate concentrations as low as 0.1 nmol L-1 Our results indicate that the e-tongue system can be used as a rapid, simple and low cost alternative in the analyses of OPs pesticide solutions below the concentration range permitted by legislation of some countries. (AU)

• FAPESP's process: 12/23880-3 - Development of polymeric nanostructures as a sensor platform for diagnosis of bacteria causing mastitis
• Grantee: Luiza Amim Mercante
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 15/13140-0 - Production and characterization of hybrid materials based on graphene/conductive polymer and applications in electronic tongue type chemical sensors
• Grantee: Murilo Henrique Moreira Facure
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 14/16789-5 - Hybrid nanostructured materials based on conjugated polymers and metallic nanoparticles for sensor applications
• Grantee: Daniel Souza Corrêa
• Support Opportunities: Regular Research Grants