Aflatoxins screening in non-dairy beverages by Mn-doped ZnS quantum dots - Molecularly imprinted polymer fluorescent probe

Synthesized molecularly imprinted polymer (MIP) materials have been anchored on the surface of PEG-Mn-doped ZnS quantum dots (QDs) to develop a fluorescence probe for aflatoxins (AFs) recognition/determination in non-dairy beverages. MIP synthesis used 5,7-dimethoxycoumarin (DMC) as a dummy template molecule, and methacrylic acid (MAA) as a functional monomer. Under optimized conditions (1.25 mL of 5 mg L-1 MIP-PEG-ZnS QDs solution, pH 5.0, and 12 min delay time before scanning), the prepared MIP-QDs composite was found to offer high affinity and selectivity for AFs (AFB1, AFB2, AFG1 and AFG2). A fast fluorimetric screening method (total AFs assessment) was therefore feasible. The limits of detection (LOD) and quantification (LOQ) were 0.016 and 0.053 mg L-1, respectively. Analytical recoveries (inter- and intra-day assays) were from 99 +/- 4% to 107 +/- 5%, with RSD (intra-day assay) lower than 13, and RSD (inter-day) lower than 7%. The optimized method was applied for total AFs assessment in several non-dairy beverage samples.