Preparation of molecularly imprinted foam for selective extraction of toxic monocrotaline from herbs

Monocrotaline (MCT), derived from most flowering plants, showed significant hepatotoxicity and carcinogenicity. Humans are easily exposed to MCT by eating traditional herbs or contaminated foods, posing a huge threat to human health. In order to selectively and conveniently separate and enrich MCT from these complex samples, we fabricated three-dimensional porous and homogeneous molecularly imprinted polymer foams (MIPFs) by using considerably inexpensive polyurethane foam (PU) as the carrier. The morphology, stability, adsorption properties and extraction parameters of MIPFs were investigated. The results indicated that an imprinted layer was coated on the surface of the carrier; the stability of MIPFs was excellent; In addition to hydrogen bonding and spatial complementarity, the electrostatic interactions were crucial for the recognition between MCT and MIPFs; MIPFs exhibited high adsorption capacity of 22.78 mg g^-1, fast mass transfer rate, and satisfactory selectivity for MCT. Subsequently, MIPFs were applied as the solid phase extraction (SPE) absorbents and combined with high performance liquid chromatography (HPLC) to enrich and detect MCT in herbal plants. The results showed that MCT could be efficiently enriched, and the impurities could be dramatically reduced. MIPFs hold great potential for selective separation and detection of MCT in complex matrices, such as traditional Chinese medicine samples and food samples.