A dual-channel fluorescent sensing system based on carbon dots and photoswitchable Pdots for sensitive detection of acetamiprid and carbendazim in food samples

The development of precise and efficient analysis technologies for acetamiprid (ACE) and carbendazim (CBZ) is of paramount importance for safeguarding the environment, ensuring food safety and protecting human health. In this study, we present a novel dual-channel fluorescent sensing system for the detection ACE and CBZ. This system integrates photoswitchable polymer dots (Pdots) and carbon dots (CDs) with aptamers and Fe 3 O 4 nanoparticles. Specifically, when irradiated with 465 nm excitation light, only the Pdots probe emits a fluorescent signal. Conversely, when irradiated with 354 nm excitation light, the Pdots probe's fluorescence is quenched, and only the CDs probe emits a signal. This innovative design eliminates interference between the fluorescent probes, thereby enhancing the accuracy and sensitivity of the detection method. Based on competitive binding between the target analytes and the complementary strands (cDNA) immobilized on magnetic Fe 3 O 4 nanoparticles with the fluorescent probes, the sensing system exhibited linear detection ranges of 1–100 ng/mL, with LODs of 0.33 ng/mL for ACE and 0.40 ng/mL for CBZ. We successfully applied this method to the analysis of ACE and CBZ in tap water, apple, and cucumber samples, achieving recoveries of 96.09 %–108.17 % and 94.59 %–109.09 %, respectively. This approach offers a highly promising tool for environmental monitoring and food safety analysis, significantly enhancing the capacity to monitor and manage potential health risks associated with these compounds.