A highly sensitive and selective “on–off–on” fluorescent aptamer sensor based on tea residue carbon quantum dots for the detection of sulfadiazine in honey

摘要

A sulfadiazine (SDZ) aptamer sensor based on carboxylated tea residue carbon quantum dots (C-TCDs) was studied to detect SDZ residues in honey. C-TCDs were synthesized by a hydrothermal method. The C-TCD labeled SDZ aptamer was used as a recognition probe, and the C-TCD labeled cDNA was used as a complementary chain to construct a fluorescent aptamer sensor. The fluorescence intensity of the constructed sensor has a good linear relationship with the concentration of SDZ in the detection range of 0–80 ng mL−1 (y = 12.857x + 828.721, R2 = 0.99768), and the detection limit is 0.95 ng mL−1. The sensor constructed using this method has good specificity and excellent anti-interference ability for ions that often appear in honey. The accuracy of the fluorescent sensor is high, the spiked recovery is 93.2–102.4, and the standard deviation is 4.5–9.7. These results show that this fluorescent sensor based on the C-TCD modified SDZ aptamer can detect SDZ residues in honey sensitively, accurately and selectively.