A dual-channel sensing platform for the cross-interference-free detection of tetracycline and copper ion

Tetracycline (TC) and copper ion (Cu²⁺), as important additives in animal feed, play a crucial role in disease prevention and growth regulation. However, the abuse leads to concentration accumulation, which seriously threatens human health and the ecological environment. There is an urgent need to develop a detection method to achieve fast and synchronous detection of these pollutants without cross-interference. Here, a carbon dots-doped lanthanide-based fluorescent nanosensor (CDs@Tb-MOFs@SiO₂-NH₂-Eu) was synthesized, which can detect TC in the 380 nm channel by "antenna effect" and internal filtering effects (IFE), and identify Cu²⁺ in the 320 nm channel. The sensor was highly sensitive to TC within 0-4 μM with a detection limit as low as 3.64 nM, and Cu²⁺ could be detected within 0-40 μM with a detection limit of 38 nM. A portable dual-channel visual fluorescence sensor was obtained by loading the probes onto test paper and cotton swabs in food samples, which indicates the practicability of this sensing strategy.