Colorimetric determination of pyrethroids based on core–shell Ag@SiO2 nanoparticles

A highly sensitive colorimetric probe for pyrethroids based on surface amine-modified silver–silica core–shell nanoparticles (Ag@SiO2-NH2 NPs) was described here. The Ag@SiO2-NH2 NPs were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) and ultraviolet–visible spectroscopy (UV–vis). The Ag@SiO2-NH2 NPs provided a simple and rapid strategy to detect pyrethroids and allowed a rapid quantitative assay of lambda-cyhalothrin (LC) down to the concentration of 1.0 × 10−6 M, which was below the European Union maximum residue limit (MRL) of 1 mg/kg. The possible mechanism that Ag@SiO2-NH2 NPs can bind well with LC through hydrogen bond interactions was discussed.