A dual-functional monomer-based molecularly imprinted fluorescent aptasensor employing near-infrared carbon dots for selective detection of quinine in food

A molecularly imprinted fluorescent aptasensor was designed for selective detection of quinine (Qn) based on dual functional monomers. In the sol-gel polymerization of molecularly imprinted polymers (MIPs), 3-aminopropyltriethoxysilane (APTES) and quinine aptamer (Apt) were employed as dual functional monomers, and Qn was the template molecule. Near-infrared carbon dots (RCDs) were used as fluorescence signal probe, and effectively avoided the interference of fluorescence emitted by Qn. Due to the diverse interaction among APTES, Apt and Qn, the near-infrared fluorescent molecularly imprinted aptasensor (RCDs-Apt@MIPs) exhibited higher specificity towards Qn than the sensor with APTES or Apt as a single functional monomer. The sensor had a wide linear range of 5.0-110.0 μM with a low detection limit of 1.7 μM. Satisfactory recovery between 93.4% and 104.0% with relative standard deviation from 1.30% to 3.60% in drinks, which showed great potential that this method can be used to detect Qn in food.