Stick-Core-Shell Magnetic Dummy Molecularly Imprinted Polymers for the Determination of Aspartame in Food Sample

Trace detection of aspartame molecules is crucial for the safety management of additives in food. We developed a convenient synthetic method to prepare magnetic dummy molecularly imprinted polymers, innovatively using carbon nanotubes as the stick carrier of the adsorptive material, which can not only improve the physicochemical stability of the material, but also allow the magnetic microsphere core to disperse due to the presence of carbon nanotubes, thereby enhancing the adsorption performance of the material. Molecularly imprinted polymers were fixed as the shell on magnetic carbon nanotubes to improve the adsorption capacity of the adsorptive material for aspartame molecules. Aspartame in food was enriched by the developed magnetic solid-phase extraction method, followed by detection using LC-MS/MS. Meanwhile, the adsorption mechanism of aspartame by magnetic dummy molecularly imprinted polymers was discussed. Due to its strong selectivity and molecular recognition ability for aspartame, an ultra-low limit of detection was achieved after treatment with magnetic dummy molecularly imprinted polymers using the magnetic solid-phase extraction method, with a detection limit of 0.001 ng/g. This adsorption material can be reused five times. The developed method showed high applicability in detecting aspartame in various different food samples on the market, indicating that the method can be used for real samples to achieve trace detection of aspartame in food.