Surface plasmon resonance based fiber-optic nanosensor for the pesticide fenitrothion utilizing Ta2O5 nanostructures sequestered onto a reduced graphene oxide matrix.

Abstract

A surface plasmon resonance study was carried out for the identification and determination of the organophosphate pesticide fenitrothion via an optical fiber sensor. A thin layer of silver was deposited on the unclad core of silica optical fiber for plasmon generation. This was followed by the deposition of asensing surface comprising a layer of tantalum(V) oxide nanoparticles sequestered in a nano-scaled matrix of reduced graphene oxide. The sensing mechanism is due to the interaction of fenitrothion with the silver film which leads to a change in refractive index.. Characterized by a wavelength interrogation scheme, the fiber-optic sensor exhibited a red shift equalling 56nm corresponding to fenitrothion concentration in the range 0.25-4μM including the blank solution. The spectral sensitivity is 24nmμM-1,the limit of detection is 38nM, and the response time is as short as 23s. The sensor is selective, repeatable and works at ambient temperature. Graphical abstractSchematic representation of thesensing mechanism of anSPR based fiber-optic fenitrothion sensor utilizing modification in refractive index of sensing surface comprising of tantalum(V) oxide (Ta2O5) nanoparticles embedded in reduced graphene oxide (rGO) caused by interaction with fenitrothion entities.