A facile and label-free SERS approach for inspection of fipronil in chicken eggs using SiO2@Au core/shell nanoparticles

Fipronil is a phenylpyrazole insecticide commonly used in agriculture and residential applications. In this paper, we reported a novel label-free surface-enhanced Raman spectroscopy (SERS) method for detection of fipronil residues in chicken eggs (mostly accumulated on the egg membrane). We fabricated the SERS substrates composed of the SiO2@Au core/shell nanoparticles and probed the contamination of fipronil residue on the egg membrane. The identification of the characteristic Raman bands of fipronil was achieved with the aid of density functional theory (DFT) calculation, with which we could analyzed the trace amount of fipronil in a quantitative way. As such, this work may provide a practical solution to quick inspection of fipronil contamination in chicken eggs or other foods. [Display omitted] •An effective SERS approach was proposed for direct inspection of fipronil in chicken eggs.•The SERS substrate composed of uniform SiO2@Au nanoparticles were fabricated with excellent SERS activity.•Low concentration of 0.1 ppm fipronil spiking to the egg membrane could be detected by the as-fabricated SERS substrate.•The first assignment of the fipronil Raman characteristic bands was achieved through DFT calculation.