Preparation of iron (III) oxide-titanium dioxide-silver nanocomposites and their application for detection of thiophanate-methyl

The serious threat of pesticides residue in food and natural environments to human health and ecosystems highlights the essentiality of developing highly sensitive detection methods. In this study, Fe 3 O 4 /TiO 2 /Ag-based surface-enhanced Raman spectroscopy (SERS) substrate was developed and it was employed to detect pesticides residue. The ferric ferrous oxide (Fe 3 O 4 ) nanoparticles were synthesized by hydrothermal method, titanium dioxide (TiO 2 ) was prepared by sol-gel method, and silver (Ag) nanoparticles were produced by chemical reduction. The Fe 3 O 4 /TiO 2 /Ag were obtained as SERS-active substrate for thiophanate-methyl (TM) detection. The Fe 3 O 4 /TiO 2 /Ag nanocomposites were analyzed by X-ray diffraction (XRD), Scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), Ultraviolet-Visible (UV), infrared spectra (IR), and cyclic voltammetry (CV). The SERS properties of Fe 3 O 4 /TiO 2 /Ag was evaluated via TM as a model and the nanocomposites showed significant SERS enhancement. The enhancement mechanisms included electromagnetic and chemical pathways were explored in detail. It was demonstrated that a nice linear relationship between the intensities of SERS peak and the logarithm of TM concentrations was obtained, ranging from 10 -9 to 10 -3 M, with the detection limit of 10 -10 M. In real sample tests (tap water and peaches), recovery rates of 97.4%-105.6% confirmed the accuracy and reliability which established a facile approach to detect analyte in agriculture, environment, food, industry, and biomedicine fields.