▎ 摘　　要

Diazinon is a typical phosphorothionate, which is widely used to prevent and control harmful organisms that endanger the agriculture productions. However, it is among the most toxic substances and can cause damage to the environment, food and human health even in very low concentrations. Hence, ultra-sensitive screening methods are urgently required for the detection of this extensively used pesticide. In this study, a rapid and sensitive fluorescence resonance energy transfer (FRET) method was developed for low concentration detection of diazinon in food. The aptamer-moclifiecl upconversion nanoparticles (Apt-UCNPs) were synthesized and conjugated with graphene oxide (GO) through pi-pi interaction. Due to the FRET between UCNPs and GO, the fluorescence was quenched. When cliazinon was added, the aptamer preferentially bound with it, caused the separation of GO, and resulted in the enhancement of fluorescent signal. Under the optimal conditions, a wide linear detection range from 0.05 to 500 ng/mL was achieved, with a limit of detection (LOD) of 0.023 ng/mL. The proposed method was successfully applied to measure cliazinon in real samples. Results showed that the proposed nanosensor offers an efficient, specific and simple approach for the detection of diazinon in food and has a high potential for food safety and quality control. (C) 2020 Elsevier B.V. All rights reserved.