A ratiometric fluorescent sensor based on AIE nanoparticles and nitrogen-doped carbon dots for rapid and sensitive detection of acetamiprid in rice†

Sensitive detection of acetamiprid (ACE) is valuable for human health and food security. Herein, a ratiometric fluorescent sensor based on AIE nanoparticles and nitrogen-doped carbon dots (luminol–Eu–NCDs) can sensitively and selectively detect ACE. luminol–Eu–NCDs were synthesized by the self-assembly of luminol–Eu nanoparticles (luminol–Eu NPs) by Eu³⁺ and luminol using the aggregation-induced emission (AIE) strategy while covalently linking to nitrogen-doped carbon dots (NCDs) synthesized using Listeria monocytogenes. In the presence of ACE, the fluorescence intensity at 542 nm decreased, with a slight decrease also observed at the 430 nm reference signal. Thus, the concentration of ACE can be accurately monitored by measuring ratiometric fluorescence emitted at 430 nm (F₄₃₀) and 542 nm (F₅₄₂) wavelengths. The luminol–Eu–NCD ratiometric fluorescent sensor design reduces errors stemming from environmental influences, thereby improving the sensor's overall accuracy. Optimal conditions yielded a fluorescence intensity ratiometric assay (F₄₃₀/F₅₄₂) with a detection limit of 89 ng mL⁻¹ for ACE (S/N = 3), exhibiting a good linear response over the concentration range of 0.1–100 μg mL⁻¹. The present method has been effectively used for the quantitative determination of ACE in rice and has shown remarkable anti-interference and reliability, which has important significance to ensure the safety of rice. This work presents a quick and efficient method for the sensitive detection of ACE contamination in grain food.