The terahertz metamaterial sensor for imidacloprid detection

Abstract

Imidacloprid has been widely used in crop pest control and disease resistance, the highly sensitive detection of imidacloprid concentration is strongly demanded in the field of food safety and the other fields. In this paper, a method to determine the concentration of imidacloprid by using the tablet instead of the liquid on a terahertz metamaterial sensor is proposed, which could avoid the influence of the water absorption in the terahertz band. The physical mechanism of the biosensing performance is verified theoretically and experimentally. It is found that the resonant frequency of the metamaterial has a red shift as the concentration of the imidacloprid tablet increases. The frequency shift is caused by the different concentrations as well as the refractive index of the imidacloprid tablet. The calculated sensitivity is 275.86 GHz/RIU and the figure of merit is 9.61. The proposed method would have important applications in the food safety industry.