Construction of three-face recognition molecularly imprinted polymers for extraction and detection of melamine via specific hydrogen bonding

Based on the principle that poly(thymine) could recognize melamine (Mel) in aqueous media and the third face of Mel could be accessed by other hydrogen bonding molecules, UiO-66-NH 2 was functionalized with poly(thymine) ssDNA and as the matrix to construct three-face recognition molecularly imprinted polymers (UDMIPs). The adsorption processes of UDMIPs towards Mel were accorded to Sips model and exhibited high adsorption capacity (Q S =10.60 mg/g) and good imprinting factor (IF=2.67). UDMIPs could reach the adsorption equilibrium within 20 min. Competitive adsorption and regeneration experiments demonstrated that UDMIPs exhibited good selectivity and reusability. The adsorption machanism was investigated by CD spectroscopy. Combined with HPLC, UDMIPs were successfully employed to detect Mel in milk samples with recovery rates ranging from 88.4% to 94.8%.