Rapid detection of heterocyclic aromatic amines in cakes by digital imaging colorimetry based on magnetic solid phase extraction with sulfonated hyper-cross-linked polymers

To improve the hydrophobicity and poor separability of hyper-cross-linked polymers (HCPs) in extraction, a porous magnetic adsorbent (Fe3O4@SHCP) was constructed by facile post-modification to introduce sulfonic acid groups and magnetic nanoparticles for the magnetic solid-phase extraction of heterocyclic aromatic amines (HAAs). Owing to the double extraction mechanism adopted by Fe3O4@SHCP, it has a high extraction efficiency for HAAs. Coupled with high-performance liquid chromatography (HPLC), 5 HAAs in baked cakes were detected at one time. Under optimal extraction conditions, the enrichment factor of HAAs was up to 952–986, with LODs at 0.05–0.3 ng·g−1. Based on the HPLC method, novel digital imaging colorimetry (DIC) was developed to accurately and rapidly monitor HAAs in cakes. Additionally, the established DIC method has been used to successfully evaluate the effect of baking temperature and duration on HAAs in baked cakes.