Rapid detection of malachite green in fish based on CdTe quantum dots coated with molecularly imprinted silica

- A fluorescent probe of MIP-coated QDs is fabricated for rapidly detecting MG in fish.
- The quenching efficiencies of MIP-coated QDs are linearly against MG concentrations.
- The detection probe is rapid response to MG with high sensitivity and selectivity.

A sensitive fluorescence sensor for the detection of malachite green (MG) was fabricated by grafting molecularly imprinted polymers (MIPs) onto the surface of CdTe quantum dots (QDs). The MIP-coated QDs were synthesized via a reverse microemulsion method using (3-aminopropyl)triethoxysilane (APTES) and tetraethyl orthosilicate (TEOS) as functional monomer and cross-linker, respectively. The optimum molar ratio of MG, functional monomer and cross-linker was 1:3:10. The MIP-coated QDs exhibited uniform spheres with diameter around 49 nm and excellent fluorescence emission at λex 370 nm. A linear relationship with two segments between the relative fluorescence intensities and the MG concentrations ranging from 0.08 to 20 μmol·L−1 could be obtained with a detection limit of 12 μg·kg−1. The fluorescent probe was successfully applied to the determination of MG in fish samples with the spiked recoveries ranging from 94.3% to 109.5% which were in accordance with those of the measurement by HPLC-UV.