Modification of electrospun nylon nanofibers using layer-by-layer films for application in flow injection electronic tongue: Detection of paraoxon pesticide in corn crop

The concern on exposure to hazardous pesticides caused by release of agrotoxic agents has motivated the development of new methods to analyze the quality of waters. This study reports on the modification of nylon nanofibers with layer-by-layer (LbL) films of conductive polypyrrole (PPy) and poly(o-ethoxyaniline) (POEA) that were assembled onto graphite interdigitated polyethylene terephtalate substrates, and used to detect pesticide in water. The electronic tongue apparatus, assembled to a flow analysis system, was able to distinguish water from different sources, with and without the presence of contaminants, at nanomolar concentrations. The practical utility of the system was demonstrated by discriminating the pesticide paraoxon in the water of corn washing in postharvest treatment, compared to water of other sources. The results presented here demonstrate the ability of the approach of modifying nylon nanofibers with LbL films of conductive polymers to be used as sensing units in the electronic tongue, to evaluate water quality regarding contamination by pesticides.