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 HSO3- 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 semi-quantitative 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. [Display omitted] •The red emissive fluorescent carbon dots (R-CDs) has been achieved the recyclable detection of MG for the first time.•The R-CDs has shown a lower detection limit for MG compared with other materials.•The fluorescence response of R-CDs for MG could be rapidly completed within 1 s•The process of MG detection could be effectively cycled for at least ten times.•The fluorescence detection beads provide a more economical and convenient method for practical applications.