Red emissive carbon dots-based polymer beads for recyclable and ultra-sensitive detection of malachite green in fish tissue

As a widely used antiparasitic agent, malachite green (MG) is a severe threat to human health with strong genotoxicity and carcinogenicity. So, simple, rapid and accurate determination of MG is significant for the food safety. This study prepared red emissive carbon dots (CDs) as a novel fluorescence sensing platform for MG detection based on the inner filter effect (IFE). The rapid sensing could be completed within 1 s with a low detection limit of 12.9 nmol/L. The fluorescence of CDs quenched by MG could be successfully in situ regenerated by further adding trace HSOa and recycled at least ten times. To realize simple detection on site, the recyclable, simple and portable detection device were fabricated by loading CDs into the polymer beads. Coupled with mobile photography and RGB (Red, Green, Blue) analysis, both the accurate quantitative analysis and semiquantitative visual analysis for the real fish samples could be achieved within 5 min. Such a simple detection mode without any instrument provides an efficient strategy for the development of fast sensing and smart detection devices.