Potential Use of Chitosan-TiO(2) Nanocomposites for the Electroanalytical Detection of Imidacloprid

The detection of toxic insecticides is a major scientific and technological challenge. In this regard, imidacloprid is a neonicotinoid that is a systemic insecticide that can accumulate in agricultural products and affect human health. This work aims to study the properties of chitosan–TiO(2) nanocomposites in which nanoparticles with high surface area serve as molecular recognition sites for electroanalytical imidacloprid detection. We show that the best sensitivity to imidacloprid was obtained using a modified electrode with a chitosan–TiO(2) nanocomposite with a 40 wt.% of TiO(2) nanoparticles. By using a three-phase effective permittivity model which includes chitosan, TiO(2), an interface layer between nanoparticles and a matrix, we showed that nanocomposites with 40 wt.% of TiO(2) the interface volume fraction reaches a maximum. At higher nanoparticle concentration, the sensitivity of the sensor decreases due to the decreasing of the interface volume fraction, agglomeration of nanoparticles and a decrease in their effective surface area. The methodology presented can be helpful in the design and optimization of polymer-based nanocomposites for a variety of applications.