A facile method for the fabrication of magnetic molecularly imprinted stir-bars: A practical example with aflatoxins in baby foods

- A simple method for the fabrication of magnetic MIP stir-bars is presented.
- Magnetite synthesis and bulk polymerization were combined to obtain the stir-bars.
- A practical example was performed with aflatoxins in baby foods.
- The presented stir-bars featured resistance, good accuracy and selectivity.

A fast and facile method for the fabrication of magnetic molecularly imprinted stir-bars (MMIP-SB) has been developed, using a combination of imprinting technology and magnetite. Magnetite was prepared in the laboratory from the raw and embedded into molecularly imprinted polymers through a process of bulk polymerization. This novel design was applied to the analysis of aflatoxins, one of the most important groups of mycotoxins in terms of occurrence and toxicity. In the context of food safety, molecularly imprinted polymers are a promising tool to achieve selective and accessible methods of extraction for different residues and contaminants. Considering the toxicity of aflatoxins, a dummy template was preferred for the synthesis of the imprinted polymers. A rapid and affordable extraction method for isolating five different aflatoxins that may be present in food was developed. The MMIP-SB was used as a conventional stir-bar and combined with high performance liquid chromatography and mass spectrometry for the determination of aflatoxin M1 in milk powder (infant formulas) and aflatoxins B1, B2, G1 and G2 in cereal-based baby foods. The results showed an average recovery of 60%, 43, 40, 44 and 39%, respectively, and RSD below 10%. These in-house prepared stir-bars featured good stirring and extraction performance, and recognition abilities, offering a good alternative to more complicated.