Silicon nitride nanoparticles-based radiative charge recombination chemiluminescence for the highly selective and sensitive detection of diquat

Diquat (DQ) is widely applied in the agriculture industry to ensure crop yield and quality, but this compound poses a serious hazard to human beings. The design of an efficient sensing platform for DQ is essential for food safety and environmental protection. Here, we developed a radiative charge recombination chemiluminescence (CL) using silicon nitride nanoparticles (Si3N4 NPs) as luminophore via hypochlorite (NaClO) activation for DQ quantification. With more active sites (N-Cl) on the surface of Si3N4 NPs, Si3N4 NPs displayed specific CL performance toward DQ. Accordingly, a new CL system for DQ detection was fabricated with satisfactory linearity (10–200 μg/L) and detection limit (6.1 μg/L), relative standard deviation (RSD) was lower than 1%. This new CL assay does not respond to other pesticides, and no interferences from metal ions that have been reported before in the DQ CL sensors. The CL mechanism was proposed that Si3N4 NPs act as the catalyst to accelerate the generation of superoxide radical (O2·−) from DQ, and then the radiative charge recombination of Si3N4 NPs occurs between the O2·− and exogenous holes for extraordinary CL emission. This work provides a general route for the construction of nanoparticle CL probe, which will aid in the monitoring of pollutants.